Due to low energy consumption, theoretical durability and lower prices, incandescent and energy-saving lamps are rapidly replacing them. But, despite the declared service life of up to 25 years, they often burn out without even serving the warranty period.

Unlike incandescent lamps, 90% of burnt-out LED lamps can be successfully repaired with your own hands, even without special training. The examples presented will help you repair failed LED lamps.

Before you start repairing an LED lamp, you need to understand its structure. Regardless of the appearance and type of LEDs used, all LED lamps, including filament bulbs, are designed the same. If you remove the walls of the lamp housing, you can see the driver inside, which is a printed circuit board with radio elements installed on it.

Any LED lamp is designed and works as follows. The supply voltage from the contacts of the electric cartridge is supplied to the terminals of the base. Two wires are soldered to it, through which voltage is supplied to the driver input. From the driver, the DC supply voltage is supplied to the board on which the LEDs are soldered.

The driver is an electronic unit - a current generator that converts the supply voltage into the current required to light the LEDs.

Sometimes, to diffuse light or protect against human contact with unprotected conductors of a board with LEDs, it is covered with diffusing protective glass.

About filament lamps

In appearance, a filament lamp is similar to an incandescent lamp. The design of filament lamps differs from LED lamps in that they do not use a board with LEDs as light emitters, but a sealed glass flask filled with gas, in which one or more filament rods are placed. The driver is located in the base.

The filament rod is a glass or sapphire tube with a diameter of about 2 mm and a length of about 30 mm, on which 28 miniature LEDs coated in series with a phosphor are attached and connected. One filament consumes about 1 W of power. My operating experience shows that filament lamps are much more reliable than those made on the basis of SMD LEDs. I believe that over time they will replace all other artificial light sources.

Examples of LED lamp repairs

Attention, the electrical circuits of LED lamp drivers are galvanically connected to the phase of the electrical network and therefore care should be taken. Touching exposed parts of a circuit connected to an electrical outlet may result in electric shock.

LED lamp repair
ASD LED-A60, 11 W on SM2082 chip

Currently, powerful LED light bulbs have appeared, the drivers of which are assembled on SM2082 type chips. One of them worked for less than a year and ended up being repaired. The light went out randomly and came on again. When you tapped it, it responded with light or extinguishing. It became obvious that the problem was poor contact.

To get to the electronic part of the lamp, you need to use a knife to pick up the diffuser glass at the point of contact with the body. Sometimes it is difficult to separate the glass, since when it is seated, silicone is applied to the fixing ring.

After removing the light-scattering glass, access to the LEDs and the SM2082 current generator microcircuit became available. In this lamp, one part of the driver was mounted on an aluminum LED printed circuit board, and the second on a separate one.

An external inspection did not reveal any defective soldering or broken tracks. I had to remove the board with LEDs. To do this, the silicone was first cut off and the board was pryed off by the edge with a screwdriver blade.

To get to the driver located in the lamp body, I had to unsolder it by heating two contacts with a soldering iron at the same time and moving it to the right.

On one side of the driver circuit board, only an electrolytic capacitor with a capacity of 6.8 μF for a voltage of 400 V was installed.

On the reverse side of the driver board, a diode bridge and two series-connected resistors with a nominal value of 510 kOhm were installed.

In order to figure out which of the boards the contact was missing, we had to connect them, observing the polarity, using two wires. After tapping the boards with the handle of a screwdriver, it became obvious that the fault lies in the board with the capacitor or in the contacts of the wires coming from the base of the LED lamp.

Since the soldering did not raise any suspicions, I first checked the reliability of the contact in the central terminal of the base. It can be easily removed if you pry it over the edge with a knife blade. But the contact was reliable. Just in case, I tinned the wire with solder.

It is difficult to remove the screw part of the base, so I decided to use a soldering iron to solder the soldering wires coming from the base. When I touched one of the soldering joints, the wire became exposed. A “cold” solder was detected. Since there was no way to get to the wire to strip it, I had to lubricate it with FIM active flux and then solder it again.

After assembly, the LED lamp consistently emitted light, despite hitting it with the handle of a screwdriver. Checking the light flux for pulsations showed that they are significant with a frequency of 100 Hz. Such an LED lamp can only be installed in luminaires for general lighting.

Driver circuit diagram
LED lamp ASD LED-A60 on SM2082 chip

The electrical circuit of the ASD LED-A60 lamp, thanks to the use of a specialized SM2082 microcircuit in the driver to stabilize the current, turned out to be quite simple.

The driver circuit works as follows. The AC supply voltage is supplied through fuse F to the rectifier diode bridge assembled on the MB6S microassembly. Electrolytic capacitor C1 smoothes out ripples, and R1 serves to discharge it when the power is turned off.

From the positive terminal of the capacitor, the supply voltage is supplied directly to the LEDs connected in series. From the output of the last LED, the voltage is supplied to the input (pin 1) of the SM2082 microcircuit, the current in the microcircuit is stabilized and then from its output (pin 2) goes to the negative terminal of capacitor C1.

Resistor R2 sets the amount of current flowing through the HL LEDs. The amount of current is inversely proportional to its rating. If the value of the resistor is decreased, the current will increase; if the value is increased, the current will decrease. The SM2082 microcircuit allows you to adjust the current value with a resistor from 5 to 60 mA.

LED lamp repair
ASD LED-A60, 11 W, 220 V, E27

The repair included another ASD LED-A60 LED lamp, similar in appearance and with the same technical characteristics as the one repaired above.

When turned on, the lamp came on for a moment and then did not shine. This behavior of LED lamps is usually associated with a driver failure. So I immediately started disassembling the lamp.

The light-scattering glass was removed with great difficulty, since along the entire line of contact with the body it was, despite the presence of a retainer, generously lubricated with silicone. To separate the glass, I had to look for a pliable place along the entire line of contact with the body using a knife, but still there was a crack in the body.

To gain access to the lamp driver, the next step was to remove the LED printed circuit board, which was pressed along the contour into the aluminum insert. Despite the fact that the board was aluminum and could be removed without fear of cracks, all attempts were unsuccessful. The board held tight.

It was also not possible to remove the board together with the aluminum insert, since it fit tightly to the case and was seated with the outer surface on silicone.

I decided to try removing the driver board from the base side. To do this, first, a knife was pryed out of the base and the central contact was removed. To remove the threaded part of the base, it was necessary to slightly bend its upper flange so that the core points would disengage from the base.

The driver became accessible and was freely extended to a certain position, but it was not possible to remove it completely, although the conductors from the LED board were sealed off.

The LED board had a hole in the center. I decided to try to remove the driver board by hitting its end through a metal rod threaded through this hole. The board moved a few centimeters and hit something. After further blows, the lamp body cracked along the ring and the board with the base of the base separated.

As it turned out, the board had an extension whose shoulders rested against the lamp body. It looks like the board was shaped this way to limit movement, although it would have been enough to fix it with a drop of silicone. Then the driver would be removed from either side of the lamp.

The 220 V voltage from the lamp base is supplied through a resistor - fuse FU to the MB6F rectifier bridge and is then smoothed out by an electrolytic capacitor. Next, the voltage is supplied to the SIC9553 chip, which stabilizes the current. Parallel connected resistors R20 and R80 between pins 1 and 8 MS set the amount of LED supply current.

The photo shows a typical electrical circuit diagram provided by the manufacturer of the SIC9553 chip in the Chinese datasheet.

This photo shows the appearance of the LED lamp driver from the installation side of the output elements. Since space allowed, to reduce the pulsation coefficient of the light flux, the capacitor at the driver output was soldered to 6.8 μF instead of 4.7 μF.

If you have to remove the drivers from the body of this lamp model and cannot remove the LED board, you can use a jigsaw to cut the lamp body around the circumference just above the screw part of the base.

In the end, all my efforts to remove the driver turned out to be useful only for understanding the LED lamp structure. The driver turned out to be OK.

The flash of the LEDs at the moment of switching on was caused by a breakdown in the crystal of one of them as a result of a voltage surge when the driver was started, which misled me. It was necessary to ring the LEDs first.

An attempt to test the LEDs with a multimeter was unsuccessful. The LEDs did not light up. It turned out that two light-emitting crystals connected in series are installed in one case, and in order for the LED to start flowing current, it is necessary to apply a voltage of 8 V to it.

A multimeter or tester turned on in resistance measurement mode produces a voltage within 3-4 V. I had to check the LEDs using a power supply, supplying 12 V to each LED through a 1 kOhm current-limiting resistor.

There was no replacement LED available, so the pads were shorted with a drop of solder instead. This is safe for driver operation, and the power of the LED lamp will decrease by only 0.7 W, which is almost imperceptible.

After repairing the electrical part of the LED lamp, the cracked body was glued with quick-drying Moment super glue, the seams were smoothed by melting the plastic with a soldering iron and leveled with sandpaper.

Just for fun, I did some measurements and calculations. The current flowing through the LEDs was 58 mA, the voltage was 8 V. Therefore, the power supplied to one LED was 0.46 W. With 16 LEDs, the result is 7.36 W, instead of the declared 11 W. Perhaps the manufacturer has indicated the total power consumption of the lamp, taking into account losses in the driver.

The service life of the ASD LED-A60, 11 W, 220 V, E27 LED lamp declared by the manufacturer raises serious doubts in my mind. In the small volume of the plastic lamp body, with low thermal conductivity, significant power is released - 11 W. As a result, the LEDs and driver operate at the maximum permissible temperature, which leads to accelerated degradation of their crystals and, as a consequence, to a sharp reduction in their time between failures.

LED lamp repair
LED smd B35 827 ERA, 7 W on BP2831A chip

An acquaintance shared with me that he bought five light bulbs like in the photo below, and after a month they all stopped working. He managed to throw away three of them, and, at my request, brought two for repairs.

The light bulb worked, but instead of bright light it emitted a flickering weak light with a frequency of several times per second. I immediately assumed that the electrolytic capacitor had swollen; usually, if it fails, the lamp begins to emit light like a strobe.

The light-scattering glass came off easily, it was not glued. It was fixed by a slot on its rim and a protrusion in the lamp body.

The driver was secured using two solders to a printed circuit board with LEDs, as in one of the lamps described above.

A typical driver circuit on the BP2831A chip taken from the datasheet is shown in the photograph. The driver board was removed and all simple radio elements were checked; they all turned out to be in good order. I had to start checking the LEDs.

The LEDs in the lamp were installed of an unknown type with two crystals in the housing and inspection did not reveal any defects. By connecting the leads of each LED in series, I quickly identified the faulty one and replaced it with a drop of solder, as in the photo.

The light bulb worked for a week and was repaired again. Shorted the next LED. A week later I had to short-circuit another LED, and after the fourth I threw out the light bulb because I was tired of repairing it.

The reason for the failure of light bulbs of this design is obvious. LEDs overheat due to insufficient heat sink surface, and their service life is reduced to hundreds of hours.

Why is it permissible to short-circuit the terminals of burnt-out LEDs in LED lamps?

The LED lamp driver, unlike a constant voltage power supply, produces a stabilized current value at the output, not a voltage. Therefore, regardless of the load resistance within the specified limits, the current will always be constant and, therefore, the voltage drop across each of the LEDs will remain the same.

Therefore, as the number of series-connected LEDs in the circuit decreases, the voltage at the driver output will also decrease proportionally.

For example, if 50 LEDs are connected in series to the driver, and each of them drops a voltage of 3 V, then the voltage at the driver output is 150 V, and if you short-circuit 5 of them, the voltage will drop to 135 V, and the current will not change.

But the efficiency of the driver assembled according to this scheme will be low and the power loss will be more than 50%. For example, for an LED light bulb MR-16-2835-F27 you will need a 6.1 kOhm resistor with a power of 4 watts. It turns out that the resistor driver will consume power that exceeds the power consumption of LEDs and placing it in a small LED lamp housing will be unacceptable due to the release of more heat.

But if there is no other way to repair an LED lamp and it is very necessary, then the resistor driver can be placed in a separate housing; anyway, the power consumption of such an LED lamp will be four times less than incandescent lamps. It should be noted that the more LEDs connected in series in a light bulb, the higher the efficiency will be. With 80 series-connected SMD3528 LEDs, you will need an 800 Ohm resistor with a power of only 0.5 W. The capacitance of capacitor C1 will need to be increased to 4.7 µF.

Finding faulty LEDs

After removing the protective glass, it becomes possible to check the LEDs without peeling off the printed circuit board. First of all, a careful inspection of each LED is carried out. If even the smallest black dot is detected, not to mention blackening of the entire surface of the LED, then it is definitely faulty.

When inspecting the appearance of the LEDs, you need to carefully examine the quality of the soldering of their terminals. One of the light bulbs being repaired turned out to have four LEDs that were poorly soldered.

The photo shows a light bulb that had very small black dots on its four LEDs. I immediately marked the faulty LEDs with crosses so that they were clearly visible.

Faulty LEDs may not have any changes in appearance. Therefore, it is necessary to check each LED with a multimeter or pointer tester turned on in resistance measurement mode.

There are LED lamps in which standard LEDs are installed in appearance, in the housing of which two crystals connected in series are mounted at once. For example, lamps of the ASD LED-A60 series. To test such LEDs, it is necessary to apply a voltage of more than 6 V to its terminals, and any multimeter produces no more than 4 V. Therefore, checking such LEDs can only be done by applying a voltage of more than 6 (recommended 9-12) V to them from the power source through a 1 kOhm resistor .

The LED is checked like a regular diode; in one direction the resistance should be equal to tens of megaohms, and if you swap the probes (this changes the polarity of the voltage supply to the LED), then it should be small, and the LED may glow dimly.

When checking and replacing LEDs, the lamp must be fixed. To do this, you can use a suitable sized round jar.

You can check the serviceability of the LED without an additional DC source. But this verification method is possible if the light bulb driver is working properly. To do this, it is necessary to apply supply voltage to the base of the LED light bulb and short-circuit the terminals of each LED in series with each other using a wire jumper or, for example, the jaws of metal tweezers.

If suddenly all the LEDs light up, it means that the shorted one is definitely faulty. This method is suitable if only one LED in the circuit is faulty. With this method of checking, it is necessary to take into account that if the driver does not provide galvanic isolation from the electrical network, as for example in the diagrams above, then touching the LED solders with your hand is unsafe.

If one or even several LEDs turn out to be faulty and there is nothing to replace them with, then you can simply short-circuit the contact pads to which the LEDs were soldered. The light bulb will work with the same success, only the luminous flux will decrease slightly.

Other malfunctions of LED lamps

If checking the LEDs showed their serviceability, then the reason for the light bulb’s inoperability lies in the driver or in the soldering areas of the current-carrying conductors.

For example, in this light bulb a cold solder connection was found on the conductor supplying power to the printed circuit board. The soot released due to poor soldering even settled on the conductive paths of the printed circuit board. The soot was easily removed by wiping with a rag soaked in alcohol. The wire was soldered, stripped, tinned and re-soldered into the board. I was lucky with the repair of this light bulb.

Of the ten failed bulbs, only one had a faulty driver and a broken diode bridge. The driver repair consisted of replacing the diode bridge with four IN4007 diodes, designed for a reverse voltage of 1000 V and a current of 1 A.

Soldering SMD LEDs

To replace a faulty LED, it must be desoldered without damaging the printed conductors. You also need to remove the replacement LED from the donor board without damaging it.

It is almost impossible to desolder SMD LEDs with a simple soldering iron without damaging their housing. But if you use a special tip for a soldering iron or put an attachment made of copper wire on a standard tip, then the problem can be easily solved.

LEDs have polarity and when replacing, you need to install it correctly on the printed circuit board. Typically, printed conductors follow the shape of the leads on the LED. Therefore, a mistake can only be made if you are inattentive. To seal an LED, it is enough to install it on a printed circuit board and heat its ends with the contact pads with a 10-15 W soldering iron.

If the LED burns out like carbon, and the printed circuit board underneath is charred, then before installing a new LED, you must clean this area of ​​the printed circuit board from burning, since it is a current conductor. When cleaning, you may find that the LED solder pads are burnt or peeled off.

In this case, the LED can be installed by soldering it to adjacent LEDs if the printed traces lead to them. To do this, you can take a piece of thin wire, bend it in half or three times, depending on the distance between the LEDs, tin it and solder it to them.

Repair of LED lamp series "LL-CORN" (corn lamp)
E27 4.6W 36x5050SMD

The design of the lamp, which is popularly called a corn lamp, shown in the photo below differs from the lamp described above, therefore the repair technology is different.

The design of LED SMD lamps of this type is very convenient for repair, since there is access to test the LEDs and replace them without disassembling the lamp body. True, I still disassembled the light bulb for fun in order to study its structure.

Checking the LEDs of an LED corn lamp is no different from the technology described above, but we must take into account that the SMD5050 LED housing contains three LEDs at once, usually connected in parallel (three dark points of the crystals are visible on the yellow circle), and during testing all three should glow.

A faulty LED can be replaced with a new one or short-circuited with a jumper. This will not affect the reliability of the lamp, only the luminous flux will decrease slightly, unnoticeably to the eye.

The driver of this lamp is assembled according to the simplest circuit, without an isolating transformer, so touching the LED terminals when the lamp is on is unacceptable. Lamps of this design must not be installed in lamps that can be reached by children.

If all the LEDs are working, it means the driver is faulty, and the lamp will have to be disassembled to get to it.

To do this, you need to remove the rim from the side opposite the base. Using a small screwdriver or a knife blade, try in a circle to find the weak spot where the rim is glued the worst. If the rim gives way, then using the tool as a lever, the rim will easily come off around the entire perimeter.

The driver was assembled according to the electrical circuit, like the MR-16 lamp, only C1 had a capacity of 1 µF, and C2 - 4.7 µF. Due to the fact that the wires going from the driver to the lamp base were long, the driver was easily removed from the lamp body. After studying its circuit diagram, the driver was inserted back into the housing, and the bezel was glued into place with transparent Moment glue. The failed LED was replaced with a working one.

Repair of LED lamp "LL-CORN" (corn lamp)
E27 12W 80x5050SMD

When repairing a more powerful lamp, 12 W, there were no failed LEDs of the same design and in order to get to the drivers, we had to open the lamp using the technology described above.

This lamp gave me a surprise. The wires leading from the driver to the socket were short, and it was impossible to remove the driver from the lamp body for repair. I had to remove the base.

The lamp base was made of aluminum, cored around the circumference and held tightly. I had to drill out the mounting points with a 1.5 mm drill. After this, the base, pryed off with a knife, was easily removed.

But you can do without drilling the base if you use the edge of a knife to pry it around the circumference and slightly bend its upper edge. You should first put a mark on the base and body so that the base can be conveniently installed in place. To securely fasten the base after repairing the lamp, it will be enough to put it on the lamp body in such a way that the punched points on the base fall into the old places. Next, press these points with a sharp object.

Two wires were connected to the thread with a clamp, and the other two were pressed into the central contact of the base. I had to cut these wires.

As expected, there were two identical drivers, feeding 43 diodes each. They were covered with heat shrink tubing and taped together. In order for the driver to be placed back into the tube, I usually carefully cut it along the printed circuit board from the side where the parts are installed.

After repair, the driver is wrapped in a tube, which is fixed with a plastic tie or wrapped with several turns of thread.

In the electrical circuit of the driver of this lamp, protection elements are already installed, C1 for protection against pulse surges and R2, R3 for protection against current surges. When checking the elements, resistors R2 were immediately found to be open on both drivers. It appears that the LED lamp was supplied with a voltage that exceeded the permissible voltage. After replacing the resistors, I didn’t have a 10 ohm one at hand, so I set it to 5.1 ohms, and the lamp started working.

Repair of LED lamp series "LLB" LR-EW5N-5

The appearance of this type of light bulb inspires confidence. Aluminum body, high quality workmanship, beautiful design.

The design of the light bulb is such that disassembling it without the use of significant physical effort is impossible. Since the repair of any LED lamp begins with checking the serviceability of the LEDs, the first thing we had to do was remove the plastic protective glass.

The glass was fixed without glue on a groove made in the radiator with a collar inside it. To remove the glass, you need to use the end of a screwdriver, which will go between the fins of the radiator, to lean on the end of the radiator and, like a lever, lift the glass up.

Checking the LEDs with a tester showed that they are working properly, therefore, the driver is faulty and we need to get to it. The aluminum board was secured with four screws, which I unscrewed.

But contrary to expectations, behind the board there was a radiator plane, lubricated with heat-conducting paste. The board had to be returned to its place and the lamp continued to be disassembled from the base side.

Due to the fact that the plastic part to which the radiator was attached was held very tightly, I decided to go the proven route, remove the base and remove the driver through the opened hole for repair. I drilled out the core points, but the base was not removed. It turned out that it was still attached to the plastic due to the threaded connection.

I had to separate the plastic adapter from the radiator. It held up just like the protective glass. To do this, a cut was made with a hacksaw for metal at the junction of the plastic with the radiator and by turning a screwdriver with a wide blade, the parts were separated from each other.

After unsoldering the leads from the LED printed circuit board, the driver became available for repair. The driver circuit turned out to be more complex than previous light bulbs, with an isolation transformer and a microcircuit. One of the 400 V 4.7 µF electrolytic capacitors was swollen. I had to replace it.

A check of all semiconductor elements revealed a faulty Schottky diode D4 (pictured below on the left). There was an SS110 Schottky diode on the board, which was replaced with an existing analog 10 BQ100 (100 V, 1 A). The forward resistance of Schottky diodes is two times less than that of ordinary diodes. The LED light came on. The second light bulb had the same problem.

Repair of LED lamp series "LLB" LR-EW5N-3

This LED lamp is very similar in appearance to the "LLB" LR-EW5N-5, but its design is slightly different.

If you look closely, you can see that at the junction between the aluminum radiator and the spherical glass, unlike the LR-EW5N-5, there is a ring in which the glass is secured. To remove the protective glass, use a small screwdriver to pry it at the junction with the ring.

Three nine super-bright crystal LEDs are installed on an aluminum printed circuit board. The board is screwed to the heatsink with three screws. Checking the LEDs showed their serviceability. Therefore, the driver needs to be repaired. Having experience in repairing a similar LED lamp "LLB" LR-EW5N-5, I did not unscrew the screws, but unsoldered the current-carrying wires coming from the driver and continued disassembling the lamp from the base side.

The plastic connecting ring between the base and the radiator was removed with great difficulty. At the same time, part of it broke off. As it turned out, it was screwed to the radiator with three self-tapping screws. The driver was easily removed from the lamp body.

The screws that fasten the plastic ring of the base are covered by the driver, and it is difficult to see them, but they are on the same axis with the thread to which the transition part of the radiator is screwed. Therefore, you can reach them with a thin Phillips screwdriver.

The driver turned out to be assembled according to a transformer circuit. Checking all elements except the microcircuit did not reveal any failures. Consequently, the microcircuit is faulty; I couldn’t even find a mention of its type on the Internet. The LED light bulb could not be repaired; it will be useful for spare parts. But I studied its structure.

Repair of LED lamp series "LL" GU10-3W

At first glance, it turned out to be impossible to disassemble a burnt-out GU10-3W LED light bulb with protective glass. An attempt to remove the glass resulted in its chipping. When great force was applied, the glass cracked.

By the way, in the lamp marking, the letter G means that the lamp has a pin base, the letter U means that the lamp belongs to the class of energy-saving light bulbs, and the number 10 means the distance between the pins in millimeters.

LED light bulbs with a GU10 base have special pins and are installed in a socket with a rotation. Thanks to the expanding pins, the LED lamp is pinched in the socket and held securely even when shaking.

In order to disassemble this LED light bulb, I had to drill a hole with a diameter of 2.5 mm in its aluminum case at the level of the surface of the printed circuit board. The drilling location must be chosen in such a way that the drill does not damage the LED when exiting. If you don’t have a drill at hand, you can make a hole with a thick awl.

Next, a small screwdriver is inserted into the hole and, acting like a lever, the glass is lifted. I removed the glass from two light bulbs without any problems. If checking the LEDs with a tester shows their serviceability, then the printed circuit board is removed.

After separating the board from the lamp body, it immediately became obvious that the current-limiting resistors had burned out in both one and the other lamp. The calculator determined their nominal value from the stripes, 160 Ohms. Since the resistors burned out in LED bulbs of different batches, it is obvious that their power, judging by the size of 0.25 W, does not correspond to the power released when the driver operates at the maximum ambient temperature.

The driver circuit board was well filled with silicone, and I did not disconnect it from the board with the LEDs. I cut off the leads of the burnt resistors at the base and soldered them to more powerful resistors that were on hand. In one lamp I soldered a 150 Ohm resistor with a power of 1 W, in the second two in parallel with 320 Ohms with a power of 0.5 W.

In order to prevent accidental contact of the resistor terminal, to which the mains voltage is connected, with the metal body of the lamp, it was insulated with a drop of hot-melt adhesive. It is waterproof and an excellent insulator. I often use it to seal, insulate and secure electrical wires and other parts.

Hot melt adhesive is available in the form of rods with a diameter of 7, 12, 15 and 24 mm in different colors, from transparent to black. It melts, depending on the brand, at a temperature of 80-150°, which allows it to be melted using an electric soldering iron. It is enough to cut a piece of the rod, place it in the right place and heat it. Hot-melt glue will acquire the consistency of May honey. After cooling it becomes hard again. When reheated, it becomes liquid again.

After replacing the resistors, the functionality of both bulbs was restored. All that remains is to secure the printed circuit board and protective glass in the lamp body.

When repairing LED lamps, I used liquid nails “Mounting” to secure printed circuit boards and plastic parts. The glue is odorless, adheres well to the surfaces of any materials, remains plastic after drying, and has sufficient heat resistance.

It is enough to take a small amount of glue on the end of a screwdriver and apply it to the places where the parts come into contact. After 15 minutes the glue will already hold.

When gluing the printed circuit board, in order not to wait, holding the board in place, since the wires were pushing it out, I additionally fixed the board at several points using hot glue.

The LED lamp began to flash like a strobe light

I had to repair a couple of LED lamps with drivers assembled on a microcircuit, the malfunction of which was the light blinking at a frequency of about one hertz, like in a strobe light.

One instance of the LED lamp began to blink immediately after being turned on for the first few seconds and then the lamp began to shine normally. Over time, the duration of the lamp's blinking after switching on began to increase, and the lamp began to blink continuously. The second instance of the LED lamp suddenly began blinking continuously.

After disassembling the lamps, it turned out that the electrolytic capacitors installed immediately after the rectifier bridges in the drivers had failed. It was easy to determine the malfunction, since the capacitor housings were swollen. But even if the capacitor looks free of external defects in appearance, then the repair of an LED light bulb with a stroboscopic effect must still begin with its replacement.

After replacing the electrolytic capacitors with working ones, the stroboscopic effect disappeared and the lamps began to shine normally.

Online calculators for determining resistor values
by color marking

When repairing LED lamps, it becomes necessary to determine the resistor value. According to the standard, modern resistors are marked by applying colored rings to their bodies. 4 colored rings are applied to simple resistors, and 5 to high-precision resistors.

LEDs for their power supply require the use of devices that will stabilize the current passing through them. In the case of indicator and other low-power LEDs, you can get by with resistors. Their simple calculation can be further simplified by using the LED Calculator.

To use high-power LEDs, you cannot do without using current-stabilizing devices - drivers. The right drivers have a very high efficiency - up to 90-95%. In addition, they provide stable current even when the power supply voltage changes. And this may be relevant if the LED is powered, for example, by batteries. The simplest current limiters - resistors - cannot provide this by their nature.

You can learn a little about the theory of linear and pulsed current stabilizers in the article “Drivers for LEDs”.

Of course, you can buy a ready-made driver. But it’s much more interesting to make it yourself. This will require basic skills in reading electrical diagrams and using a soldering iron. Let's look at a few simple homemade driver circuits for high-power LEDs.

Simple driver. Assembled on a breadboard, powers the mighty Cree MT-G2

A very simple linear driver circuit for an LED. Q1 – N-channel field-effect transistor of sufficient power. Suitable, for example, IRFZ48 or IRF530. Q2 is a bipolar NPN transistor. I used 2N3004, you can use any similar one. Resistor R2 is a 0.5-2W resistor that will determine the driver current. Resistance R2 2.2Ohm provides a current of 200-300mA. The input voltage should not be very high - it is advisable not to exceed 12-15V. The driver is linear, so the driver efficiency will be determined by the ratio V LED / V IN, where V LED is the voltage drop across the LED, and V IN is the input voltage. The greater the difference between the input voltage and the drop across the LED and the greater the driver current, the more the transistor Q1 and resistor R2 will heat up. However, V IN should be greater than V LED by at least 1-2V.

For tests, I assembled the circuit on a breadboard and powered it with a powerful CREE MT-G2 LED. The power supply voltage is 9V, the voltage drop across the LED is 6V. The driver worked immediately. And even with such a small current (240mA), the mosfet dissipates 0.24 * 3 = 0.72 W of heat, which is not small at all.

The circuit is very simple and can even be mounted in a finished device.

The circuit of the next homemade driver is also extremely simple. It involves the use of a step-down voltage converter chip LM317. This microcircuit can be used as a current stabilizer.

An even simpler driver on the LM317 chip

The input voltage can be up to 37V, it must be at least 3V higher than the voltage drop across the LED. The resistance of resistor R1 is calculated by the formula R1 = 1.2 / I, where I is the required current. The current should not exceed 1.5A. But at this current, resistor R1 should be able to dissipate 1.5 * 1.5 * 0.8 = 1.8 W of heat. The LM317 chip will also get very hot and will not be possible without a heatsink. The driver is also linear, so in order for the efficiency to be maximum, the difference between V IN and V LED should be as small as possible. Since the circuit is very simple, it can also be assembled by hanging installation.

On the same breadboard, a circuit was assembled with two one-watt resistors with a resistance of 2.2 Ohms. The current strength turned out to be less than the calculated one, since the contacts in the breadboard are not ideal and add resistance.

The next driver is a pulse buck driver. It is assembled on the QX5241 chip.

The circuit is also simple, but consists of a slightly larger number of parts and here you can’t do without making a printed circuit board. In addition, the QX5241 chip itself is made in a fairly small SOT23-6 package and requires attention when soldering.

The input voltage should not exceed 36V, the maximum stabilization current is 3A. The input capacitor C1 can be anything - electrolytic, ceramic or tantalum. Its capacity is up to 100 µF, the maximum operating voltage is no less than 2 times greater than the input. Capacitor C2 is ceramic. Capacitor C3 is ceramic, capacity 10 μF, voltage - no less than 2 times greater than the input. Resistor R1 must have a power of at least 1W. Its resistance is calculated by the formula R1 = 0.2 / I, where I is the required driver current. Resistor R2 - any resistance 20-100 kOhm. The Schottky diode D1 must withstand the reverse voltage with a reserve - at least 2 times the value of the input. And it must be designed for a current not less than the required driver current. One of the most important elements of the circuit is field-effect transistor Q1. This should be an N-channel field device with the lowest possible resistance in the open state; of course, it should withstand the input voltage and the required current strength with a reserve. A good option is field-effect transistors SI4178, IRF7201, etc. Inductor L1 should have an inductance of 20-40 μH and a maximum operating current not less than the required driver current.

The number of parts of this driver is very small, all of them are compact in size. The result may be a fairly miniature and, at the same time, powerful driver. This is a pulse driver, its efficiency is significantly higher than that of linear drivers. However, it is recommended to select an input voltage that is only 2-3V higher than the voltage drop across the LEDs. The driver is also interesting because output 2 (DIM) of the QX5241 chip can be used for dimming - regulating the driver current and, accordingly, the brightness of the LED. To do this, pulses (PWM) with a frequency of up to 20 KHz must be supplied to this output. Any suitable microcontroller can handle this. The result may be a driver with several operating modes.

(13 ratings, average 4.58 out of 5)

LEDs are replacing types of light sources such as fluorescent and incandescent lamps. Almost every home already has LED lamps; they consume much less than their two predecessors (up to 10 times less than incandescent lamps and 2 to 5 times less than CFLs or energy-saving fluorescent lamps). In situations where a long light source is needed, or it is necessary to organize illumination of a complex shape, it is used.

LED strip is ideal for a number of situations; its main advantage over individual LEDs and LED matrices is power supplies. They are easier to find for sale in almost any electrical goods store, unlike drivers for high-power LEDs, and besides, the selection of a power supply is carried out only by power consumption, because The vast majority of LED strips have a supply voltage of 12 Volts.

While for high-power LEDs and modules, when choosing a power source, you need to look for a current source with the required power and rated current, i.e. take into account 2 parameters, which complicates the selection.

This article discusses typical power supply circuits and their components, as well as tips for repairing them for novice radio amateurs and electricians.

Types and requirements for power supplies for LED strips and 12 V LED lamps

The main requirement for a power source for both LEDs and LED strips is high-quality voltage/current stabilization, regardless of mains voltage surges, as well as low output ripple.

Based on the type of design, power supplies for LED products are divided into:

Sealed. They are more difficult to repair; the body cannot always be carefully disassembled, and the inside may even be filled with sealant or compound.

Non-hermetic, for indoor use. Better amenable to repair, because... The board is removed after unscrewing several screws.

By cooling type:

Passive air. The power supply is cooled due to natural air convection through the perforations of its housing. Disadvantage is the inability to achieve high power while maintaining weight and size indicators;

Active air. The power supply is cooled using a cooler (a small fan, as installed on PC system units). This type of cooling allows you to achieve more power in the same size with a passive power supply.

Power supply circuits for LED strips

It is worth understanding that in electronics there is no such thing as a “power supply for an LED strip”; in principle, any power supply with a suitable voltage and a current greater than that consumed by the device will be suitable for any device. This means that the information described below applies to almost any power supply.

However, in everyday life it is easier to talk about a power supply according to its purpose for a specific device.

General structure of a switching power supply

Switching power supplies (UPS) have been used to power LED strips and other equipment for the last decades. They differ from transformer ones in that they operate not at the frequency of the supply voltage (50 Hz), but at high frequencies (tens and hundreds of kilohertz).

Therefore, for its operation, a high-frequency generator is needed; in cheap power supplies designed for low currents (units of amperes), a self-oscillator circuit is often found; it is used in:

electronic transformers;

electronic ballasts for fluorescent lamps;

mobile phone chargers;

cheap UPS for LED strips (10-20 W) and other devices.

A diagram of such a power supply can be seen in the figure (click on the picture to enlarge):

Its structure is as follows:

The OS includes an optocoupler U1, with its help the power part of the oscillator receives a signal from the output and maintains a stable output voltage. There may be no voltage in the output part due to a break in the VD8 diode, often this is a Schottky assembly and must be replaced. A swollen electrolytic capacitor C10 also often causes problems.

As you can see, everything works with a much smaller number of elements, the reliability is appropriate...

More expensive power supplies

The circuits that you will see below are often found in power supplies for LED strips, DVD players, radio tape recorders and other low-power devices (tens of watts).

Before moving on to considering popular circuits, familiarize yourself with the structure of a switching power supply with a PWM controller.

The upper part of the circuit is responsible for filtering, rectifying and smoothing the ripples of the mains voltage 220, essentially similar to both the previous type and the subsequent ones.

The most interesting thing is the PWM block, the heart of any decent power supply. A PWM controller is a device that controls the duty cycle of an output signal based on a user-defined setpoint or current or voltage feedback. PWM can control both load power using a field (bipolar, IGBT) switch, and a semiconductor controlled switch as part of a converter with a transformer or inductor.

By changing the width of the pulses at a given frequency, you also change the effective value of the voltage, while maintaining the amplitude, you can integrate it using C- and LC-circuits to eliminate ripple. This method is called Pulse Width Modeling, that is, modeling a signal using the pulse width (duty factor/duty factor) at a constant frequency.

In English it sounds like a PWM-controller, or Pulse-Width Modulation controller.

The figure shows bipolar PWM. Rectangular signals are control signals on transistors from the controller; the dotted line shows the shape of the voltage in the load of these switches - the effective voltage.

Higher-quality low-average power supplies are often built on integrated PWM controllers with a built-in power switch. Advantages over self-oscillator circuit:

The operating frequency of the converter does not depend on either the load or the supply voltage;

Better stabilization of output parameters;

Possibility of simpler and more reliable adjustment of the operating frequency at the stage of design and modernization of the unit.

Below are several typical power supply circuits (click on the picture to enlarge):

Here RM6203 is both a controller and a key in one housing.

The same thing, but on a different chip.

Feedback is carried out using a resistor, sometimes an optocoupler connected to an input called Sense (sensor) or Feedback (feedback). Repair of such power supplies is generally similar. If all the elements are working properly, and the supply voltage is supplied to the microcircuit (Vdd or Vcc leg), then the problem is most likely in it, more accurately looking at the output signals (drain, gate leg).

Almost always, you can replace such a controller with any analogue with a similar structure; to do this, you need to check the datasheet against the one installed on the board and the one you have and solder it, observing the pinout, as shown in the following photographs.

Or here is a schematic representation of the replacement of such microcircuits.

Powerful and expensive power supplies

Power supplies for LED strips, as well as some power supplies for laptops, are made on the UC3842 PWM controller.

The scheme is more complex and reliable. The main power component is transistor Q2 and transformer. During repairs, you need to check the filtering electrolytic capacitors, the power switch, Schottky diodes in the output circuits and output LC filters, the supply voltage of the microcircuit, otherwise the diagnostic methods are similar.

However, more detailed and accurate diagnostics are only possible using an oscilloscope; otherwise, checking for short circuits on the board, soldering of elements and breaks will cost more. Replacing suspicious nodes with known working ones can help.

More advanced models of power supplies for LED strips are made on the almost legendary TL494 chip (any letters with the numbers “494”) or its analogue KA7500. By the way, most AT and ATX computer power supplies are built on these same controllers.

Here is a typical power supply diagram for this PWM controller (click on the diagram):

Such power supplies are highly reliable and stable.

Brief verification algorithm:

1. We power the microcircuit according to the pinout from an external power source of 12-15 volts (12 leg is plus, and 7 leg is minus).

2. A voltage of 5 Volts should appear on the 14 legs, which will remain stable when the power supply changes; if it “floats” - the microcircuit needs to be replaced.

3. There should be a sawtooth voltage at pin 5; you can “see” it only with the help of an oscilloscope. If it is not there or the shape is distorted, we check compliance with the nominal values ​​of the timing RC circuit, which is connected to pins 5 and 6; if not, in the diagram these are R39 and C35, they must be replaced; if nothing has changed after that, the microcircuit has failed.

4. There should be rectangular pulses at outputs 8 and 11, but they may not exist due to the specific feedback implementation circuit (pins 1-2 and 15-16). If you turn off and connect 220 V, they will appear there for a while and the unit will go into protection again - this is a sign of a working microcircuit.

5. You can check the PWM by short-circuiting the 4th and 7th legs, the pulse width will increase, and short-circuiting the 4th to 14th legs, the pulses will disappear. If you get different results, the problem is in MS.

This is the most brief test of this PWM controller; there is a whole book about repairing power supplies based on them, “Switching Power Supplies for IBM PC.”

Although it is dedicated to computer power supplies, there is a lot of useful information for any radio amateur.

Conclusion

The circuitry of power supplies for LED strips is similar to any power supplies with similar characteristics; they can be repaired, modernized, and adjusted to the required voltages quite well, of course, within reasonable limits.

LED light sources are quickly gaining popularity and replacing uneconomical incandescent lamps and dangerous fluorescent analogues. They use energy efficiently, last a long time, and some of them can be repaired after failure.

To properly replace or repair a broken element, you will need an LED lamp circuit and knowledge of design features. And we examined this information in detail in our article, paying attention to the types of lamps and their design. We also provided a brief overview of the devices of the most popular LED models from well-known manufacturers.

A close acquaintance with the design of an LED lamp may be required only in one case - if it is necessary to repair or improve the light source.

Home craftsmen, having a set of elements on hand, can use LEDs, but a beginner cannot do it.

Considering that LED devices have become the basis of lighting systems for modern apartments, the ability to understand the structure of lamps and repair them can save a significant part of the family budget

But, having studied the circuit and having basic skills in working with electronics, even a beginner will be able to disassemble the lamp, replace broken parts, restoring the functionality of the device. To find detailed instructions for identifying a breakdown and self-repairing an LED lamp, please go to.

Does it make sense to repair an LED lamp? Undoubtedly. Unlike analogues with incandescent filaments for 10 rubles apiece, LED devices are expensive.

Let’s assume that a GAUSS “pear” costs about 80 rubles, and a better alternative OSRAM costs 120 rubles. Replacing a capacitor, resistor or diode will cost less, and the life of the lamp can be extended by timely replacement.

There are many modifications of LED lamps: candles, pears, balls, spotlights, capsules, strips, etc. They differ in shape, size and design. To clearly see the difference from an incandescent lamp, consider the common pear-shaped model.

Instead of a glass bulb there is a matte diffuser, the filament is replaced by “long-playing” diodes on the board, excess heat is removed by a radiator, and voltage stability is ensured by the driver

If you look away from the usual form, you can notice only one familiar element - . The size range of socles remains the same, so they fit traditional sockets and do not require changing the electrical system. But this is where the similarities end: the internal structure of LED devices is much more complex than that of incandescent lamps.

LED lamps are not designed to operate directly from a 220 V network, so a driver is located inside the device, which is both a power supply and control unit. It consists of many small elements, the main task of which is to rectify the current and reduce the voltage.

Types of schemes and their features

To create the optimal voltage for operation of the device, diodes are assembled based on a circuit with a capacitor or step-down transformer. The first option is cheaper, the second is used to equip high-power lamps.

There is a third type - inverter circuits, which are implemented either for assembling dimmable lamps, or for devices with a large number of diodes.

Option #1 - with capacitors to reduce voltage

Let's consider an example involving a capacitor, since such circuits are common in household lamps.

Elementary circuit of an LED lamp driver. The main elements that dampen the voltage are capacitors (C2, C3), but resistor R1 also performs the same function

Capacitor C1 protects against power line interference, and C4 smoothes out ripples. At the moment the current is supplied, two resistors - R2 and R3 - limit it and at the same time protect it from a short circuit, and the VD1 element converts alternating voltage.

When the current supply stops, the capacitor is discharged using resistor R4. By the way, R2, R3 and R4 are not used by all manufacturers of LED products.

Option #4 – Jazzway 7.5w GU10 lamp

The external elements of the lamp are easily detached, so you can get to the controller quickly enough by unscrewing two pairs of screws. The protective glass is held in place by latches. The board contains 17 diodes with serial communication.

However, the controller itself, located in the base, is generously filled with compound, and the wires are pressed into the terminals. To free them, you need to use a drill or use desoldering.

Conclusions and useful video on the topic

Homemade from scrap elements:

Nowadays, on commercial Internet sites you can purchase kits and individual elements for assembling lighting fixtures of various powers.

If desired, you can repair a failed LED lamp or modify a new one to get a better result. When purchasing, we recommend that you carefully check the characteristics and suitability of the parts.

Do you still have questions after reading the material above? Or do you want to add valuable information and other light bulb diagrams based on your personal experience in repairing LED lamps? Write your recommendations, add photos and diagrams, ask questions in the comments block below.

Homemade driver for LEDs from a 220V network. Ice driver circuits

DIY LED driver: simple circuits with descriptions

Using LEDs as lighting sources usually requires a specialized driver. But it happens that the necessary driver is not at hand, but you need to organize lighting, for example, in a car, or test the LED for brightness. In this case, you can make a driver for the LEDs yourself.

How to make a driver for LEDs

The circuits below use the most common elements that can be purchased at any radio store. No special equipment is required during assembly - all necessary tools are widely available. Despite this, with a careful approach, the devices work for quite a long time and are not much inferior to commercial samples.

Required materials and tools

In order to assemble a homemade driver, you will need:

• Soldering iron with a power of 25-40 W. You can use more power, but this increases the risk of overheating of the elements and their failure. It is best to use a soldering iron with a ceramic heater and a non-burning tip, because... a regular copper tip oxidizes quite quickly and has to be cleaned.
• Flux for soldering (rosin, glycerin, FKET, etc.). It is advisable to use a neutral flux - unlike active fluxes (phosphoric and hydrochloric acids, zinc chloride, etc.), it does not oxidize the contacts over time and is less toxic. Regardless of the flux used, after assembling the device, it is better to wash it with alcohol. For active fluxes this procedure is mandatory, for neutral ones - to a lesser extent.
• Solder. The most common is low-melting tin-lead solder POS-61. Lead-free solders are less harmful when inhaling fumes during soldering, but have a higher melting point with lower fluidity and a tendency to degrade the weld over time.
• Small pliers for bending leads.
• Wire cutters or side cutters for cutting long ends of leads and wires.
• Installation wires are insulated. Stranded copper wires with a cross-section of 0.35 to 1 mm2 are best suited.
• Multimeter for monitoring voltage at nodal points.
• Electrical tape or heat shrink tubing.
• A small prototype board made of fiberglass. A board measuring 60x40 mm will be sufficient.

PCB development board for quick installation

Simple driver circuit for 1 W LED

One of the simplest circuits for powering a powerful LED is shown in the figure below:

As you can see, in addition to the LED, it includes only 4 elements: 2 transistors and 2 resistors.

The powerful n-channel field-effect transistor VT2 acts here as a regulator of the current passing through the LED. Resistor R2 determines the maximum current passing through the LED and also acts as a current sensor for transistor VT1 in the feedback circuit.

The more current passes through VT2, the greater the voltage drops across R2, accordingly VT1 opens and lowers the voltage at the gate of VT2, thereby reducing the LED current. In this way, stabilization of the output current is achieved.

The circuit is powered from a constant voltage source of 9 - 12 V, a current of at least 500 mA. The input voltage should be at least 1-2 V greater than the voltage drop across the LED.

Resistor R2 should dissipate 1-2 W of power, depending on the required current and supply voltage. Transistor VT2 is n-channel, designed for a current of at least 500 mA: IRF530, IRFZ48, IRFZ44N. VT1 – any low-power bipolar npn: 2N3904, 2N5088, 2N2222, BC547, etc. R1 – power 0.125 - 0.25 W with a resistance of 100 kOhm.

Due to the small number of elements, assembly can be carried out by hanging installation:

Another simple driver circuit based on the LM317 linear controlled voltage regulator:

Here the input voltage can be up to 35 V. The resistor resistance can be calculated using the formula:

where I is the current strength in amperes.

In this circuit, the LM317 will dissipate significant power given the large difference between the supply voltage and the LED drop. Therefore, it will have to be placed on a small radiator. The resistor must also be rated for at least 2 W.

This scheme is discussed more clearly in the following video:

Here we show how to connect a powerful LED using batteries with a voltage of about 8 V. When the voltage drop across the LED is about 6 V, the difference is small, and the chip does not heat up much, so you can do without a heatsink.

Please note that if there is a large difference between the supply voltage and the drop across the LED, it is necessary to place the microcircuit on a heat sink.

Power driver circuit with PWM input

Below is a circuit for powering high-power LEDs:

The driver is built on a dual comparator LM393. The circuit itself is a buck-converter, that is, a pulse step-down voltage converter.

Driver Features

• Supply voltage: 5 - 24 V, constant;
• Output current: up to 1 A, adjustable;
• Output power: up to 18 W;
• Output short circuit protection;
• The ability to control brightness using an external PWM signal (it will be interesting to read how to adjust the brightness of an LED strip using a dimmer).

Operating principle

Resistor R1 with diode D1 form a source of reference voltage of about 0.7 V, which is additionally regulated by variable resistor VR1. Resistors R10 and R11 serve as current sensors for the comparator. As soon as the voltage across them exceeds the reference one, the comparator will close, thus closing the pair of transistors Q1 and Q2, and they, in turn, will close the transistor Q3. However, inductor L1 at this moment tends to resume the flow of current, so the current will flow until the voltage at R10 and R11 becomes less than the reference voltage, and the comparator opens transistor Q3 again.

The pair of Q1 and Q2 acts as a buffer between the output of the comparator and the gate of Q3. This protects the circuit from false positives due to interference on the Q3 gate, and stabilizes its operation.

The second part of the comparator (IC1 2/2) is used for additional brightness control using PWM. To do this, the control signal is applied to the PWM input: when TTL logic levels (+5 and 0 V) ​​are applied, the circuit will open and close Q3. The maximum signal frequency at the PWM input is about 2 KHz. This input can also be used to turn the device on and off using the remote control.

D3 is a Schottky diode, rated for current up to 1 A. If you cannot find a Schottky diode, you can use a pulse diode, for example FR107, but the output power will then decrease slightly.

The maximum output current is adjusted by selecting R2 and turning on or off R11. This way you can get the following values:

• 350 mA (1 W LED): R2=10K, R11 disabled,
• 700 mA (3 W): R2=10K, R11 connected, nominal 1 Ohm,
• 1A (5W): R2=2.7K, R11 connected, nominal 1 Ohm.

Within narrower limits, adjustment is made using a variable resistor and a PWM signal.

Assembling and configuring the driver

The driver components are mounted on a breadboard. First, the LM393 chip is installed, then the smallest components: capacitors, resistors, diodes. Then transistors are installed, and lastly a variable resistor.

It is better to place elements on the board in such a way as to minimize the distance between the connected pins and use as few wires as jumpers as possible.

When connecting, it is important to observe the polarity of the diodes and the pinout of the transistors, which can be found in the technical description for these components. You can also check diodes using a multimeter in resistance measurement mode: in the forward direction, the device will show a value of about 500-600 Ohms.

To power the circuit, you can use an external DC voltage source of 5-24 V or batteries. 6F22 (“crown”) and other batteries have too small a capacity, so their use is impractical when using high-power LEDs.

After assembly, you need to adjust the output current. To do this, LEDs are soldered to the output, and the VR1 engine is set to the lowest position according to the diagram (checked with a multimeter in the “testing” mode). Next, we apply the supply voltage to the input, and by rotating the VR1 knob we achieve the required brightness.

List of elements:

Conclusion

The first two of the considered circuits are very simple to manufacture, but they do not provide short circuit protection and have rather low efficiency. For long-term use, the third circuit on LM393 is recommended, since it does not have these disadvantages and has greater capabilities for adjusting the output power.

ledno.ru

220V LED driver circuit

The advantages of LED paws have been discussed many times. The abundance of positive reviews from users of LED lighting willy-nilly makes you think about Ilyich’s own light bulbs. Everything would be nice, but when it comes to calculating the conversion of an apartment to LED lighting, the numbers are a little “straining”.

To replace an ordinary 75W lamp, you need a 15W LED bulb, and a dozen such lamps need to be replaced. With an average cost of about $10 per lamp, the budget comes out to be decent, and the risk of purchasing a Chinese “clone” with a life cycle of 2-3 years cannot be ruled out. In light of this, many are considering the possibility of making these devices themselves.

Power theory for LED lamps from 220V

The most budget option can be assembled with your own hands from these LEDs. A dozen of these little ones cost less than a dollar, and the brightness corresponds to a 75W incandescent lamp. Putting everything together is not a problem, but if you don’t connect them directly to the network, they will burn out. The heart of any LED lamp is the power driver. It determines how long and how well the light bulb will shine.

To assemble a 220-volt LED lamp with your own hands, let’s look at the power driver circuit.

The network parameters significantly exceed the needs of the LED. In order for the LED to operate from the network, it is necessary to reduce the voltage amplitude, current strength and convert the alternating voltage of the network into direct voltage.

For these purposes, a voltage divider with a resistor or capacitive load and stabilizers are used.

Components of a LED luminaire

A 220-volt LED lamp circuit will require a minimum number of available components.

• LEDs 3.3V 1W – 12 pcs.;
• ceramic capacitor 0.27 µF 400-500V – 1 pc.;
• resistor 500kOhm - 1Mohm 0.5 - 1W - 1 pcs.t;
• 100V diode – 4 pcs.;
• electrolytic capacitors 330 μF and 100 μF 16V 1 pc.;
• 12V voltage stabilizer L7812 or similar – 1 pc.

Making a 220V LED driver with your own hands

The 220 volt ice driver circuit is nothing more than a switching power supply.

As a homemade LED driver from a 220V network, we will consider the simplest switching power supply without galvanic isolation. The main advantage of such schemes is simplicity and reliability. But be careful when assembling, since this circuit has no current limit. The LEDs will draw their required one and a half amperes, but if you touch the bare wires with your hand, the current will reach tens of amperes, and such a shock of current is very noticeable.

The simplest driver circuit for 220V LEDs consists of three main stages:

• Capacitive voltage divider;
• diode bridge;
• voltage stabilization cascade.

The first stage is capacitance on capacitor C1 with a resistor. The resistor is necessary for self-discharge of the capacitor and does not affect the operation of the circuit itself. Its rating is not particularly critical and can be from 100 kOhm to 1 Mohm with a power of 0.5-1 W. The capacitor is necessarily non-electrolytic at 400-500V (effective peak voltage of the network).

When a half-wave of voltage passes through a capacitor, it passes current until the plates are charged. The smaller its capacity, the faster the full charge occurs. With a capacity of 0.3-0.4 μF, the charging time is 1/10 of the half-wave period of the mains voltage. In simple terms, only a tenth of the incoming voltage will pass through the capacitor.

The second stage is a diode bridge. It converts alternating voltage to direct voltage. After cutting off most of the half-wave voltage with a capacitor, we get about 20-24V DC at the output of the diode bridge.

The third stage is a smoothing stabilizing filter.

A capacitor with a diode bridge acts as a voltage divider. When the voltage in the network changes, the amplitude at the output of the diode bridge will also change.

To smooth out the voltage ripple, we connect an electrolytic capacitor in parallel to the circuit. Its capacity depends on the power of our load.

In the driver circuit, the supply voltage for the LEDs should not exceed 12V. The common element L7812 can be used as a stabilizer.

The assembled circuit of a 220-volt LED lamp begins to work immediately, but before connecting it to the network, carefully insulate all exposed wires and soldering points of circuit elements.

Driver option without current stabilizer

There are a huge number of driver circuits on the network for LEDs from a 220V network that do not have current stabilizers.

The problem with any transformerless driver is the ripple of the output voltage, and therefore the brightness of the LEDs. A capacitor installed after the diode bridge partially copes with this problem, but does not completely solve it.

There will be ripple on the diodes with an amplitude of 2-3V. When we install a 12V stabilizer in the circuit, even taking into account ripple, the amplitude of the incoming voltage will be higher than the cutoff range.

Voltage diagram in a circuit without a stabilizer

Diagram in a circuit with a stabilizer

Therefore, a driver for diode lamps, even one assembled with one’s own hands, will not be inferior in pulsation level to similar units of expensive factory-made lamps.

As you can see, assembling the driver with your own hands is not particularly difficult. By changing the parameters of the circuit elements, we can vary the output signal values ​​within wide limits.

If you want to build a 220-volt LED floodlight circuit based on such a circuit, it is better to convert the output stage to 24V with an appropriate stabilizer, since the output current of the L7812 is 1.2A, this limits the load power to 10W. For more powerful lighting sources, it is necessary to either increase the number of output stages, or use a more powerful stabilizer with an output current of up to 5A and install it on a radiator.

svetodiodinfo.ru

How to choose an LED driver, led driver

The most optimal way to connect to 220V, 12V is to use a current stabilizer or LED driver. In the language of the intended enemy it is written “led driver”. By adding the desired power to this request, you can easily find a suitable product on Aliexpress or Ebay.

• 1. Features of Chinese
• 2. Service life
• 3. LED driver 220V
• 4. RGB driver 220V
• 5. Module for assembly
• 6. Driver for LED lamps
• 7. Power supply for LED strip
• 8. DIY LED driver
• 9. Low voltage
• 10. Brightness adjustment

Features of Chinese

Many people like to buy from the largest Chinese bazaar, Aliexpress. prices and assortment are good. LED driver is most often chosen due to its low cost and good performance.

But with the rise in the dollar exchange rate, it became unprofitable to buy from the Chinese, the cost became equal to the Russian one, and there was no guarantee or possibility of exchange. For cheap electronics, the characteristics are always overestimated. For example, if the power specified is 50 watts, at best this is the maximum short-term power, not constant. The nominal will be 35W - 40W.

In addition, they save a lot on the filling to reduce the price. In some places there are not enough elements that ensure stable operation. The cheapest components are used, with a short service life and low quality, so the defect rate is relatively high. As a rule, components operate at the limit of their parameters, without any reserve.

If the manufacturer is not listed, then he does not have to be responsible for the quality and no review will be written about his product. And the same product is produced by several factories in different configurations. For good products, the brand must be indicated, which means that he is not afraid to be responsible for the quality of his products.

One of the best is the MeanWell brand, which values ​​the quality of its products and does not produce junk.

Life time

Like any electronic device, the LED driver has a service life that depends on operating conditions. Branded modern LEDs already work up to 50-100 thousand hours, so the power fails earlier.

Classification:

1. consumer goods up to 20,000 hours;
2. average quality up to 50,000 hours;
3. up to 70,000h. power supply using high-quality Japanese components.

This indicator is important when calculating long-term payback. There is enough consumer goods for household use. Although the miser pays twice, and this works great in LED spotlights and lamps.

LED driver 220V

Modern LED drivers are designed using a PWM controller, which can stabilize the current very well.

Main parameters:

1. rated power;
2. operating current;
3. number of connected LEDs;
4. Power factor;
5. Stabilizer efficiency.

Housings for outdoor use are made of metal or impact-resistant plastic. When the case is made of aluminum, it can act as a cooling system for electronic components. This is especially true when filling the body with compound.

The markings often indicate how many LEDs can be connected and what power. This value can be not only fixed, but also in the form of a range. For example, it is possible to connect 12 220 LEDs from 4 to 7 pieces of 1W each. It depends on the LED driver circuit design.

RGB driver 220V

Three-color RGB LEDs differ from single-color LEDs in that they contain crystals of different colors (red, blue, and green) in one housing. To control them, each color must be lit separately. For diode strips, an RGB controller and power supply are used for this.

If a power of 50W is indicated for an RGB LED, then this is the total for all 3 colors. To find out the approximate load on each channel, divide 50W by 3, we get about 17W.

In addition to powerful led drivers, there are also 1W, 3W, 5W, 10W.

There are 2 types of remote controls. With infrared control, like a TV. With radio control, the remote control does not need to be pointed at the signal receiver.

Assembly module

If you are interested in an LED driver for assembling an LED spotlight or lamp with your own hands, then you can use an LED driver without a housing.

If you already have a current stabilizer for LEDs that is not suitable for the current strength, then you can increase or decrease it. Find the PWM controller chip on the board, on which the characteristics of the LED driver depend. There is a marking on it, by which you need to find the specifications for it. The documentation will indicate a typical connection diagram. Typically, the output current is set by one or more resistors connected to the pins of the microcircuit. If you change the value of the resistors or install a variable resistance according to the information from the specifications, you can change the current. Just do not exceed the initial power, otherwise it may fail.

Driver for LED lamps

There are slightly different requirements for the power supply of street lighting equipment. When designing street lighting, it is taken into account that the LED driver will work in conditions from -40° to +40° in dry and humid air.

The ripple factor for luminaires may be higher than for indoor use. For street lighting, this indicator becomes unimportant.

When operating outdoors, the power supply must be completely sealed. There are several ways to protect against moisture:

1. filling the entire board with sealant or compound;
2. assembly of the block using silicone seals;
3. placement of the LED driver board in the same volume as the LEDs.

The maximum level of protection is IP68, designated as “Waterproof LED Driver” or “waterproof electronic led driver”. For the Chinese, this is not a guarantee of waterproofness.

In my experience, the stated level of protection against moisture and dust does not always correspond to the real one. In some places there may not be enough seals. Pay attention to the cable entry and exit from the housing; there are samples with a hole that is not closed with sealant or other means. Water through the cable will be able to flow into the housing and then evaporate within it. This will cause corrosion on the board and exposed wires. This will greatly reduce the life of the spotlight or lamp.

Power supply for LED strip

LED strip works on a different principle; it requires a stabilized voltage. The current-setting resistor is installed on the tape itself. This simplifies the connection process; you can connect a piece of any length ranging from 3cm to 100m.

Therefore, power for the LED strip can be made from any 12V power supply from consumer electronics.

Main parameters:

1. number of volts at the output;
2. rated power;
3. degree of protection against moisture and dust
4. Power factor.

DIY LED driver

You can make a simple DIY driver in 30 minutes, even if you don’t know the basics of electronics. As a voltage source, you can use a power supply from consumer electronics with a voltage from 12V to 37V. The power supply from a laptop is especially suitable, it has 18 - 19V and a power from 50W to 90W.

A minimum of parts will be required, all of them are shown in the picture. A heatsink for cooling a powerful LED can be borrowed from a computer. Surely somewhere at home in a closet you have old spare parts from the system unit gathering dust. Best suited from the processor.

To find out the required resistance value, use the current stabilizer calculator for LM317.

Before making a 50W led driver with your own hands, it’s worth searching a little, for example, every diode lamp contains it. If you have a faulty light bulb whose diodes are faulty, then you can use the driver from it.

Low voltage

We will analyze in detail the types of low-voltage ice drivers operating from voltages up to 40 volts. Our Chinese brothers-in-mind offer many options. Voltage stabilizers and current stabilizers are produced on the basis of PWM controllers. The main difference is that the module with the ability to stabilize the current has 2-3 blue regulators on the board, in the form of variable resistors.

The technical characteristics of the entire module are indicated by the PWM parameters of the microcircuit on which it is assembled. For example, the outdated but popular LM2596 according to its specifications holds up to 3 Amperes. But without a radiator it will only handle 1 Ampere.

A more modern option with improved efficiency is the XL4015 PWM controller designed for 5A. With a miniature cooling system it can operate up to 2.5A.

If you have very powerful, super-bright LEDs, then you need an LED driver for LED lamps. Two radiators cool the Schottky diode and the XL4015 chip. In this configuration, it is capable of operating up to 5A with voltage up to 35V. It is advisable that it does not operate in extreme conditions, this will significantly increase its reliability and service life.

If you have a small lamp or pocket spotlight, then a miniature voltage stabilizer with a current of up to 1.5A is suitable for you. Input voltage from 5 to 23V, output up to 17V.

Brightness adjustment

To regulate the brightness of the LED, you can use compact LED dimmers that have appeared recently. If its power is not enough, then you can install a larger dimmer. They usually operate in two ranges: 12V and 24V.

You can control it using an infrared or radio remote control (RC). They cost from 100 rubles for a simple model and from 200 rubles for a model with a remote control. Basically, such remote controls are used for 12V diode strips. But it can easily be connected to a low-voltage driver.

Dimming can be analog in the form of a rotary knob or digital in the form of buttons.

led-obzor.ru

LED DRIVER

We'll look at a really simple and inexpensive high-power LED driver. The circuit is a constant current source, which means it keeps the LED brightness constant no matter what power you use. If a resistor is sufficient to limit the current of small, ultra-bright LEDs, then for powers above 1 watt a special circuit is needed. In general, it is better to power an LED this way than using a resistor. The proposed LED driver is ideal especially for high-power LEDs, and can be used for any number and configuration of them, with any type of power supply. As a test project, we took a 1 watt LED element. You can easily change the driver elements for use with more powerful LEDs, for different types of power supply - power supply, batteries, etc.

LED driver specifications:

Input voltage: 2V to 18V - output voltage: 0.5 less than input voltage (0.5V drop across FET) - current: 20 amps

Details on the diagram:

R2: approximately 100 ohm resistor

R3: resistor is selected

Q2: small NPN transistor (2N5088BU)

Q1: Large N-channel transistor (FQP50N06L)

LED: Luxeon 1-watt LXHL-MWEC

Other driver elements:

A transformer adapter is used as a power source; you can use batteries. To power one LED, 4 - 6 volts is enough. That's why this circuit is convenient because you can use a wide range of power sources and it will always light the same way. A heatsink is not required, since about 200 mA of current flows. If more current is planned, you should install the LED element and transistor Q1 on the heatsink.

Select resistance R3

The LED current is set using R3, it is approximately equal to: 0.5 / R3

Power dissipated by resistor approximately: 0.25 / R3

In this case, the current is set to 225 mA using R3 at 2.2 ohms. R3 has a power of 0.1 W, so a standard 0.25 W resistor is fine. Transistor Q1 will operate up to 18V. If you want more, you need to change the model. Without heatsinks, the FQP50N06L can only dissipate about 0.5 W - that's enough for 200 mA of current with a 3-volt difference between the power supply and the LED.

Functions of transistors in the diagram:

Q1 is used as a variable resistor. - Q2 is used as a current sensor and R3 is a setting resistor that causes Q2 to close when increased current flows. The transistor creates feedback that continuously monitors the current current parameters and keeps it exactly at the specified value.

This circuit is so simple that there is no point in assembling it on a printed circuit board. Simply connect the leads of the parts using a surface-mounted connection.

Forum on power supply of various LEDs

elwo.ru

Drivers for LED light bulbs.

A small laboratory on the topic “which driver is better?” Electronic or on capacitors as ballast? I think everyone has their own niche. I will try to consider all the pros and cons of both schemes. Let me remind you of the formula for calculating ballast drivers. Maybe someone is interested? I will base my review on a simple principle. First, I’ll look at capacitor-based drivers as ballast. Then I'll look at their electronic counterparts. Well, at the end there is a comparative conclusion. Now let's get down to business. We take a standard Chinese light bulb. Here is its diagram (slightly improved). Why improved? This circuit will fit any cheap Chinese light bulb. The only difference will be in the ratings of the radio components and the absence of some resistances (in order to save money).
There are light bulbs with missing C2 (very rare, but it happens). In such light bulbs the pulsation coefficient is 100%. It is very rare to use R4. Although resistance R4 is simply necessary. It will replace the fuse and will also soften the starting current. If it is not in the diagram, it is better to install it. The current through the LEDs determines the rating of capacitance C1. Depending on how much current we want to pass through the LEDs (for DIYers), we can calculate its capacity using formula (1).
I have written this formula many times. I repeat. Formula (2) allows us to do the opposite. With its help, you can calculate the current through the LEDs, and then the power of the light bulb, without having a Wattmeter. To calculate power, we also need to know the voltage drop across the LEDs. You can measure it with a voltmeter, or you can simply count it (without a voltmeter). It's easy to calculate. The LED behaves in the circuit like a zener diode with a stabilization voltage of about 3V (there are exceptions, but very rare). When LEDs are connected in series, the voltage drop across them is equal to the number of LEDs multiplied by 3V (if there are 5 LEDs, then 15V, if 10 - 30V, etc.). It's simple. It happens that circuits are assembled from LEDs in several parallels. Then it will be necessary to take into account the number of LEDs in only one parallel. Let's say we want to make a light bulb with ten 5730smd LEDs. According to the passport data, the maximum current is 150mA. Let's calculate a 100mA light bulb. There will be a power reserve. Using formula (1) we get: C=3.18*100/(220-30)=1.67 μF. The industry does not produce such a capacity, not even the Chinese one. We take the nearest convenient one (we have 1.5 μF) and recalculate the current using formula (2). (220-30)*1.5/3.18=90mA. 90mA*30V=2.7W. This is the rated power of the light bulb. It's simple. In life, of course, it will be different, but not much. It all depends on the actual voltage in the network (this is the first minus of the driver), on the exact capacity of the ballast, the actual voltage drop across the LEDs, etc. Using formula (2) you can calculate the power of light bulbs already purchased (already mentioned). The voltage drop across R2 and R4 can be neglected; it is insignificant. You can connect quite a lot of LEDs in series, but the total voltage drop should not exceed half the mains voltage (110V). If this voltage is exceeded, the light bulb reacts painfully to all voltage changes. The more it exceeds, the more painfully it reacts (this is friendly advice). Moreover, beyond these limits the formula does not work accurately. It is no longer possible to calculate exactly. Now these drivers have a very big advantage. The power of the light bulb can be adjusted to the desired result by selecting capacity C1 (both homemade and already purchased). But then a second minus appeared. The circuit has no galvanic isolation from the network. If you poke an indicator screwdriver anywhere in the switched-on light bulb, it will show the presence of a phase. Touching (the light bulb plugged in) with your hands is strictly prohibited. Such a driver has almost 100% efficiency. Losses are only on diodes and two resistances. It can be made within half an hour (quick). It’s not even necessary to etch the board. I ordered these capacitors: aliexpress.com/snapshot/310648391.html aliexpress.com/snapshot/310648393.html These are the diodes: aliexpress.com/snapshot/6008595825.html

But these schemes have another serious drawback. These are pulsations. Ripple with a frequency of 100 Hz, the result of rectification of the mains voltage.
The shape of different light bulbs will vary slightly. It all depends on the size of the filter capacity C2. The larger the capacity, the smaller the humps, the less pulsation. It is necessary to look at GOST R 54945-2012. And there it is written in black and white that pulsations with a frequency of up to 300 Hz are harmful to health. There is also a formula for calculation (Appendix D). But that's not all. It is necessary to look at the Sanitary Standards SNiP 23-05-95 “NATURAL AND ARTIFICIAL LIGHTING”. Depending on the purpose of the room, the maximum permissible pulsations are from 10 to 20%. Nothing in life just happens. The result of the simplicity and low cost of light bulbs is obvious. It's time to move on to electronic drivers. Here, too, not everything is so rosy. This is the driver I ordered. This is the link to it at the beginning of the review.
Why did you order this one? Will explain. I wanted to “collectively farm” lamps using 1-3W LEDs myself. I chose it based on price and characteristics. I would be satisfied with a driver for 3-4 LEDs with a current of up to 700mA. The driver must contain a key transistor, which will relieve the driver control chip. To reduce RF ripple, there should be a capacitor at the output. First minus. The cost of such drivers (US $13.75 / 10 pieces) differs more from ballast ones. But here's a plus. The stabilization currents of such drivers are 300mA, 600mA and higher. Ballast drivers would never dream of this (I don’t recommend more than 200mA). Let's look at the characteristics from the seller: ac85-265v" that everyday household appliances." load after 10-15v; can drive 3-4 3w led lamp beads series 600ma But the output voltage range is too small (also a minus). A maximum of five LEDs can be connected in series. At the same time, you can pick up as much as you like. LED power is calculated by the formula: Driver current multiplied by the voltage drop across the LEDs [number of LEDs (from three to five) and multiplied by the voltage drop across the LED (about 3V)]. Another big drawback of these drivers is high RF interference. Some units not only hear FM radio, but also lose reception of digital TV channels when they are operating. The conversion frequency is several tens of kHz. But, as a rule, there is no protection (from interference).
There is something like a “screen” under the transformer. Should reduce interference. It is this driver that produces almost no noise. Why they emit noise becomes clear if you look at the voltage oscillogram on the LEDs. Without capacitors, the Christmas tree is much more serious!
The driver output should contain not only an electrolyte, but also ceramics to suppress RF interference. Expressed his opinion. Usually it costs one or the other. Sometimes it costs nothing. This happens in cheap light bulbs. The driver is hidden inside, making it difficult to file a claim. Let's look at the diagram. But I’ll warn you, it’s for informational purposes only. I applied only the basic elements that we need for creativity (to understand “what’s what”).

There is an error in the calculations. By the way, at low power levels the device also fluctuates. Now let’s count the pulsations (the theory at the beginning of the review). Let's see what our eye sees. I connect a photodiode to the oscilloscope. I combined two pictures into one for ease of perception. The light on the left is off. On the right - the light is on. We look at GOST R 54945-2012. And there it is written in black and white that pulsations with a frequency of up to 300 Hz are harmful to health. And we have about 100Hz. Harmful for the eyes.
I got 20%. It is necessary to look at the Sanitary Standards SNiP 23-05-95 “NATURAL AND ARTIFICIAL LIGHTING”. Can be used, but not in the bedroom. And I have a corridor. You don’t have to look at SNiP. Now let's look at another option for connecting LEDs. This is a wiring diagram for the electronic driver.
Total 3 parallels of 4 LEDs. This is what the Wattmeter shows. 7.1W active power.
Let's see how much reaches the LEDs. I connected an ammeter and a voltmeter to the driver output.
Let's calculate the pure LED power. P=0.49A*12.1V=5.93W. Everything that is missing is taken care of by the driver. Now let's see what our eye sees. The light on the left is off. On the right - the light is on. Pulse repetition frequency is about 100 kHz. We look at GOST R 54945-2012. And there it is written in black and white that only pulsations with a frequency of up to 300 Hz are harmful to health. And we have about 100 kHz. It is harmless to the eyes.

I examined everything, measured everything. Now I will highlight the pros and cons of these circuits: Disadvantages of light bulbs with a capacitor as ballast compared to electronic drivers. -During operation, you categorically cannot touch the circuit elements, they are under phase. -It is impossible to achieve high LED luminescence currents, because This requires large capacitors. And an increase in capacity leads to large inrush currents, damaging the switches. -Large pulsations of the light flux with a frequency of 100 Hz require large filter capacitors at the output. Advantages of light bulbs with a capacitor as ballast compared to electronic drivers. +The circuit is very simple and does not require any special skills in manufacturing. +The output voltage range is simply fantastic. The same driver will work with both one and forty LEDs connected in series. Electronic drivers have a much narrower output voltage range. +Low cost of such drivers, which literally consists of the cost of two capacitors and a diode bridge. +You can make it yourself. Most parts can be found in any shed or garage (old TVs, etc.). +You can regulate the current through the LEDs by selecting the ballast capacity. +Indispensable as an initial LED experience, as the first step in mastering LED lighting. There is one more quality that can be attributed to both pros and cons. When using similar circuits with backlit switches, the LEDs of the light bulb are illuminated. For me personally, this is more of a plus than a minus. I use it everywhere as emergency (night) lighting. I deliberately do not write which drivers are better; each has its own niche. I gave everything I know to the maximum. Showed all the pros and cons of these schemes. And as always, the choice is yours to make. I just tried to help. That's all! Good luck everyone.

mysku.ru

How to choose an LED driver - types and main characteristics

LEDs have become very popular. The main role in this was played by the LED driver, which maintains a constant output current of a certain value. We can say that this device is a current source for LED devices. This current driver, working together with the LED, provides long service life and reliable brightness. Analysis of the characteristics and types of these devices allows you to understand what functions they perform and how to choose them correctly.

What is a driver and what is its purpose?

An LED driver is an electronic device whose output produces a direct current after stabilization. In this case, it is not voltage that is generated, but rather current. Devices that stabilize voltage are called power supplies. The output voltage is indicated on their body. 12 V power supplies are used to power LED strips, LED strips and modules.

The main parameter of the LED driver, which it can provide to the consumer for a long time at a certain load, is the output current. Individual LEDs or assemblies of similar elements are used as a load.

The LED driver is usually powered from a 220 V mains voltage. In most cases, the operating output voltage range is from three volts and can reach several tens of volts. To connect six 3W LEDs, you will need a driver with an output voltage from 9 to 21 V, rated at 780 mA. Despite its versatility, it has low efficiency if a minimum load is applied to it.

When lighting in cars, in the headlights of bicycles, motorcycles, mopeds, etc., when equipping portable lamps, constant voltage power is used, the value of which varies from 9 to 36 V. You can not use a driver for LEDs with low power, but in such In cases, it will be necessary to add a corresponding resistor to the 220 V supply network. Despite the fact that this element is used in household switches, connecting an LED to a 220 V network and counting on reliability is quite problematic.

Key Features

The power that these devices are capable of delivering under load is an important indicator. Don't overload it trying to achieve maximum results. As a result of such actions, drivers for LEDs or the LED elements themselves may fail.

The electronic content of the device is influenced by many reasons:

• device protection class;
• elemental component that is used for assembly;
• input and output parameters;
• manufacturer's brand.

The production of modern drivers is carried out using microcircuits using pulse-width conversion technology, which includes pulse converters and current-stabilizing circuits. PWM converters are powered from 220 V, have a high class of protection against short circuits, overloads, as well as high efficiency.

Specifications

Before purchasing an LED converter, you should study the characteristics of the device. These include the following parameters:

• output power;
• output voltage;
• rated current.

LED driver connection diagram

The output voltage is affected by the connection diagram to the power source and the number of LEDs in it. The current value depends proportionally on the power of the diodes and the brightness of their radiation. The LED driver must supply as much current to the LEDs as required to ensure constant brightness. It is worth remembering that the power of the required device should be greater than that consumed by all LEDs. It can be calculated using the following formula:

P(led) – power of one LED element;

n - number of LED elements.

To ensure long-term and stable operation of the driver, the device’s power reserve should be 20–30% of the nominal one.

When performing calculations, you should take into account the color factor of the consumer, as it affects the voltage drop. It will have different meanings for different colors.

Best before date

LED drivers, like all electronics, have a certain service life, which is greatly influenced by operating conditions. LED elements manufactured by well-known brands are designed to last up to 100 thousand hours, which is much longer than power sources. Based on the quality, the calculated driver can be classified into three types:

• low quality, with service life up to 20 thousand hours;
• with average parameters - up to 50 thousand hours;
• converter consisting of components from well-known brands - up to 70 thousand hours.

Many people don’t even know why they should pay attention to this parameter. This will be needed to select a device for long-term use and further payback. For use in domestic premises, the first category is suitable (up to 20 thousand hours).

How to choose a driver?

There are many types of drivers used for LED lighting. Most of the products presented are made in China and do not have the required quality, but they stand out due to their low price range. If you need a good driver, it is better not to go for cheap Chinese products, since their characteristics do not always coincide with those stated, and they rarely come with a warranty. There may be a defect on the microcircuit or rapid failure of the device; in this case, it will not be possible to exchange for a better product or return the funds.

The most commonly chosen option is a boxless driver, powered by 220 V or 12 V. Various modifications allow them to be used for one or more LEDs. These devices can be chosen for organizing research in the laboratory or conducting experiments. For phyto-lamps and household use, drivers for LEDs located in the housing are chosen. Frameless devices win in terms of price, but lose in aesthetics, safety and reliability.

Types of drivers

Devices that supply power to LEDs can be divided into:

• pulse;
• linear.

Pulse-type devices produce many high-frequency current pulses at the output and operate on the PWM principle, their efficiency is up to 95%. Pulse converters have one significant drawback - strong electromagnetic interference occurs during operation. To ensure a stable output current, a current generator is installed in the linear driver, which plays the role of an output. Such devices have low efficiency (up to 80%), but are technically simple and inexpensive. Such devices cannot be used for high power consumers.

From the above, we can conclude that the power source for LEDs should be chosen very carefully. An example would be a fluorescent lamp that is supplied with a current that exceeds the norm by 20%. There will be virtually no changes in its characteristics, but the performance of the LED will decrease several times.

lampagid.ru

Schemes for connecting LEDs to 220V and 12V

Let's consider ways to connect medium-power ice diodes to the most popular ratings of 5V, 12 volts, 220V. Then they can be used in the manufacture of color and music devices, signal level indicators, smooth switching on and off. I’ve been planning to make a smooth artificial dawn for a long time in order to maintain my daily routine. In addition, dawn emulation allows you to wake up much better and easier.

Read about connecting LEDs to 12 and 220V in the previous article; all methods are discussed, from complex to simple, from expensive to cheap.

• 1. Types of circuits
• 2. Designation on the diagram
• 3. Connecting the LED to a 220V network, diagram
• 4. Connection to DC voltage
• 5. The simplest low voltage driver
• 6. Drivers with power supply from 5V to 30V
• 7. Turn on 1 diode
• 8. Parallel connection
• 9. Serial connection
• 10. RGB LED connection
• 11. Turning on COB diodes
• 12. Connecting SMD5050 for 3 crystals
• 13. LED strip 12V SMD5630
• 14. LED strip RGB 12V SMD5050

Types of circuits

There are two types of LED connection diagrams, which depend on the power source:

1. LED driver with stabilized current;
2. power supply with stabilized voltage.

In the first option, a specialized source is used, which has a certain stabilized current, for example 300mA. The number of connected LED diodes is limited only by its power. No resistor (resistance) is required.

In the second option, only the voltage is stable. The diode has very low internal resistance; if you turn it on without ampere limitation, it will burn out. To turn it on, you must use a current-limiting resistor. The calculation of the resistor for the LED can be done using a special calculator.

The calculator takes into account 4 parameters:

• voltage reduction on one LED;
• rated operating current;
• number of LEDs in the circuit;
• number of volts at the output of the power supply.

If you use inexpensive Chinese-made LED elements, then most likely they will have a wide range of parameters. Therefore, the actual Ampere value of the circuit will be different and the set resistance will need to be adjusted. To check how large the spread of parameters is, you need to turn everything on sequentially. We connect power to the LEDs and then lower the voltage until they barely glow. If the characteristics differ greatly, then some of the LEDs will work brightly, and some will work dimly.

This leads to the fact that some elements of the electrical circuit will have higher power, and because of this they will be more heavily loaded. There will also be increased heating, increased degradation, and lower reliability.

Designation on the diagram

The above two pictograms are used for designation in the diagram. Two parallel arrows indicate that the light is very strong, the number of bunnies in your eyes cannot be counted.

Connecting an LED to a 220V network, diagram

To connect to a 220 volt network, a driver is used, which is a source of stabilized current.

The driver circuit for LEDs comes in two types:

1. simple on a quenching capacitor;
2. full-fledged using stabilizer chips;

Assembling a driver on a capacitor is very simple; it requires a minimum of parts and time. The 220V voltage is reduced by a high-voltage capacitor, which is then rectified and slightly stabilized. It is used in cheap LED lamps. The main disadvantage is the high level of light pulsations, which is bad for health. But this is individual, some people don’t notice it at all. It is also difficult to calculate the circuit due to the variation in the characteristics of the electronic components.

A complete circuit using custom ICs ensures better stability in the driver output. If the driver copes well with the load, then the ripple factor will not be higher than 10%, and ideally 0%. In order not to make a driver yourself, you can take it from a faulty light bulb or lamp, if the problem was not with the power supply.

If you have a more or less suitable stabilizer, but the current strength is less or more, then it can be adjusted with a minimum of effort. Find the technical specifications for the chip from the driver. Most often, the number of Amperes at the output is set by a resistor or several resistors located next to the microcircuit. By adding resistance to them or removing one of them, you can obtain the required current strength. The only thing is not to exceed the specified power.

DC connection

1. 3.7V – batteries from phones;
2. 5V – USB chargers;
3. 12V – car, cigarette lighter, consumer electronics, computer;
4. 19V – blocks from laptops, netbooks, monoblocks.

The simplest low voltage driver

The simplest current stabilizer circuit for LEDs consists of a linear microcircuit LM317 or its analogues. The output of such stabilizers can be from 0.1A to 5A. The main disadvantages are low efficiency and strong heating. But this is compensated by the maximum ease of manufacture.

Input up to 37V, up to 1.5 Amperes for the housing indicated in the picture.

To calculate the resistance that sets the operating current, use the current stabilizer calculator on LM317 for LEDs.

Drivers with power supply from 5V to 30V

If you have a suitable power source from any household appliance, then it is better to use a low-voltage driver to turn it on. They can be up or down. A booster will make even 1.5V 5V so that the LED circuit works. A step-down from 10V-30V will make a lower one, for example 15V.

They are sold in a large variety by the Chinese; the low-voltage driver differs in two regulators from a simple Volt stabilizer.

The actual power of such a stabilizer will be lower than what the Chinese indicated. In the module parameters, they write the characteristics of the microcircuit and not the entire structure. If there is a large radiator, then such a module will handle 70% - 80% of what was promised. If there is no radiator, then 25% - 35%.

Particularly popular are models based on LM2596, which are already quite outdated due to low efficiency. They also get very hot, so without a cooling system they do not hold more than 1 Ampere.

XL4015, XL4005 are more efficient, the efficiency is much higher. Without a cooling radiator, they can withstand up to 2.5A. There are very miniature models based on MP1584 measuring 22mm by 17mm.

Turn on 1 diode

The most commonly used are 12 volts, 220 volts and 5V. This is how low-power LED lighting of 220V wall switches is made. Factory standard switches most often have a neon lamp installed.

Parallel connection

When connecting in parallel, it is advisable to use a separate resistor for each series circuit of diodes in order to obtain maximum reliability. Another option is to put one powerful resistor on several LEDs. But if one LED fails, the current on the remaining ones will increase. By whole it will be higher than the nominal or specified value, which will significantly reduce the resource and increase heating.

The rationality of using each method is calculated based on the requirements for the product.

Serial connection

Serial connection when powered from 220V is used in filament diodes and LED strips at 220 volts. In a long chain of 60-70 LEDs, each one drops 3V, which allows it to be connected directly to high voltage. Additionally, only a current rectifier is used to obtain plus and minus.

This connection is used in any lighting technology:

1. LED lamps for home;
2. led lamps;
3. New Year's garlands for 220V;
4. LED strips 220.

Lamps for the home usually use up to 20 LEDs connected in series; the voltage across them is about 60V. The maximum quantity is used in Chinese corn light bulbs, from 30 to 120 LED pieces. Corns do not have a protective flask, so the electrical contacts on which up to 180V are completely open.

Be careful if you see a long series string, and they are not always grounded. My neighbor grabbed the corn with his bare hands and then recited fascinating poems from bad words.

RGB LED connection

Low-power three-color RGB LEDs consist of three independent crystals located in one housing. If 3 crystals (red, green, blue) are turned on simultaneously, we get white light.

Each color is controlled independently of the others using an RGB controller. The control unit has ready-made programs and manual modes.

Turning on COB diodes

The connection diagrams are the same as for single-chip and three-color LEDs SMD5050, SMD 5630, SMD 5730. The only difference is that instead of 1 diode, a series circuit of several crystals is included.

Powerful LED matrices contain many crystals connected in series and in parallel. Therefore, power is required from 9 to 40 volts, depending on the power.

Connecting SMD5050 for 3 crystals

The SMD5050 differs from conventional diodes in that it consists of 3 white light crystals, and therefore has 6 legs. That is, it is equal to three SMD2835 made on the same crystals.

When connected in parallel using one resistor, reliability will be lower. If one of the crystals fails, the current through the remaining 2 increases. This leads to accelerated burnout of the remaining ones.

By using a separate resistance for each crystal, the above disadvantage is eliminated. But at the same time, the number of resistors used increases by 3 times and the LED connection circuit becomes more complex. Therefore, it is not used in LED strips and lamps.

LED strip 12V SMD5630

A clear example of connecting an LED to 12 volts is an LED strip. It consists of sections of 3 diodes and 1 resistor connected in series. Therefore, it can only be cut in the indicated places between these sections.

LED strip RGB 12V SMD5050

RGB tape uses three colors, each is controlled separately, and a resistor is installed for each color. You can cut only at the indicated location, so that each section has 3 SMD5050 and can be connected to 12 volts.

led-obzor.ru Connection diagrams for sockets and switches

LED driver circuits