How to design and check the withstand voltage circuit of LED lamp

The old design 50 years ago, the reverse leakage current measurement, remember to limit the current.

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Because of this, he offended Hu Jun, and he still persevered after being forced to be laid off.

The simple detection method of LED light *** is as follows:

First, look at the appearance

Appearance is the easiest way to decide. First of all, it is necessary to observe whether the outer packaging is regular. Whether there is a key address, trademark, certificate, CCC qualification certificate, etc. Secondly, check the quality of the materials used in the lamp, mainly observing the wiring process, the materials used for the bottom plate and the quality of the mask.

Second, look at the light source

The biggest role of electric lights is naturally lighting. However, there are also advantages and disadvantages of lighting, and inferior light sources are extremely destructive to the atmosphere and vision. When purchasing, you can turn on the electric light and remove the mask.

Make the light source cast directly on the wall. Observe the wall, high-quality light source, uniform brightness distribution, no light spots.

3. Look at the fever

It is normal for electric lamps to generate heat after being energized, but different quality lamps have different heating effects. After the light is powered on for a while, remove the mask and touch the beads with your hands. High-quality electric lamps, the lamp beads heat evenly as a whole, and the temperature is not hot.

The lifespan of LED lights.

Theoretically, the life of LED lamps is generally in 100,000 hours, and LED lamps must have a certain power, the greater the power, the higher the heat dissipation requirements, if the heat dissipation effect is not good, it will directly affect the life of LED.

And the life of LED has a lot to do with current, brightness, materials, etc., when the LED lamp is used for more than 1000 hours, there will be light decay, that is to say, its brightness is not as bright as it was at the beginning.

Adjust the multimeter to the transistor position, place it directly on the lamp bead, and you can test. The battery tests the quality of the LED beads. The Chinese name of LED is "light-emitting diode", which refers to the luminaire of the lamp, also called "lamp beads".

LED is a type of diode, and diode is a type of transistor. Therefore, in order to measure whether the LED is damaged, it is necessary to use the transistor of a multimeter. (There are many ways to measure LEDs with a multimeter.)

Here are just the simplest and most suitable methods for home use. How to test led lamp beads? 1.

Observe the appearance of the lamp beads and distinguish the anode and cathode of the lamp beads. A simple detection method for LEDs. 2.

Turn the multimeter gear and select the transistor setting. 3.When tested, a set of data is displayed on the multimeter showing the bias of the diode's PN junction.

Of course, when measuring LEDs, you don't need to look at any data. You just need to observe whether the LED light can light up during the measurement. 4.

If the light is on, it means that the function of the lamp bead is basically unimpeded. If not, test the red and black probes again. In case the magnetic poles of some lamp beads are opposite to the general ones.

How to detect if an LED light is broken? Identification method of positive and negative poles of LED lamp beads: 1

The LED beads used in the indicator light have two long pins underneath. 2.The long needle has the positive electrode, and the short needle has the negative electrode.

If the two pins are cut to the same length, you can hold the lamp bead and look at the metal rod inside. The corresponding pins under the small metal rod are the positive electrode, and the large one is the negative electrode. 3.

Since the pins of the SMD LED are blocked, you can look down at the LED lamp beads. The end with colored lines or missing corners is the negative pole. 2.

How to test LED lamp beads: How to judge the LED light power drive? The multimeter can't detect it, you can simply test whether the input and output are short-circuited.

If it is the simplest resistor-capacitance constant current source, you can test whether the capacitor is short-circuited. As long as the capacitor is not short-circuited, it will light up when the LED string is connected. LED driver power supply is the key to LED light, it is like a person's heart.

In order to make high-quality LED lamps for lighting, it is necessary to abandon the constant voltage mode that drives LEDs. The constant current source drive is an LED drive mode, which is driven by a constant current source, and there is no need to connect the current limiting resistor in series in the output circuit. The current flowing through the LED is not affected by the change of external power supply voltage, the change of ambient temperature and the discreteness of LED parameters, and the current can be constant, giving full play to the excellent characteristics of LED.

How to judge the quality of LED beads? LED constant current power supply is used to power LED lights. Since the current flowing through the LED will be automatically detected and controlled during the operation of the power supply, there is no need to worry about the excessive current flowing through the LED at the moment of power-on, and there is no need to worry about the load short circuit burning out the power supply.

The constant current drive mode can avoid the current change caused by the change of LED DC voltage, and the constant current can stabilize the brightness of the LED, which is also convenient for the LED lamp factory to ensure the consistency of the product when implementing mass production. Therefore, many manufacturers have fully realized the importance of dynamic power supply, and many LED light manufacturers have given up the constant voltage mode to drive LED lights with slightly higher costs.

LED lamps are tested for the following reasons:

1. Because the lamp is turned on in the process of opening, the voltage received will have an instantaneous impulse voltage, and at this time, there will be a large current, and once the current leakage is too much, it may cause harm to the human body.

2. Generally speaking, the high voltage is to prevent the damage caused to the product when the large flow is generated, and on the other hand, it is also to test the insulation performance of the product and verify whether the insulation performance is effective. If the shell assembly gap of the lamp itself is small and there is a certain misalignment of the assembly mating surface, it can roughly withstand the 2500V high voltage applied on the live parts and the shell plastic, and it should be ensured that these mating surfaces and plastic materials will not melt and deform during normal operation, so that the insulation performance of the lamp itself should be met.

Supplemental Measurement Methods:

1. Connect the plug of the high-voltage machine to the "220V" jack, then connect the high-voltage machine to the power supply and turn on all switches.

2. Adjust the power supply "voltage" and "time" files of the high-voltage machine to the required position of the required test lamp body, start each test button to check whether the "voltage", "leakage current" and "test time" are consistent with the test requirements.

3. Then use the probe rod of the high-voltage machine to contact the grounding terminal (GND), if there is an alarm at this time, it means that the high-voltage machine is normal and can be used.

4. Contact the plug of the lamp body to the iron sheet or socket of the grounding terminal (GND) of the high-voltage machine, and then click on any part of the metal or conductive part of the lamp body with the metal part of the high-voltage probe, if the high-voltage machine does not alarm, it means that the high-voltage test of the lamp has passed; If there is an alarm, it means that this light does not pass.

LED, chip inspection, 1Temperature.

2.Luminous flux.

3.Color coordinates, color rendering index, etc., these parameters need to be checked by the integrating sphere.

The question you asked was only about whether the LED was lit or not:

1.The LED can be tested by using a constant current power supply (pay attention to the impact of the branch in the middle of the process, and pay attention to whether the electrical parameters meet the LED driving parameters when the constant current source is debugged).

2.High-power LEDs are generally turned on between the delay voltage, and they can be tested with 2 dry cell batteries (note: current limiting, it is best to connect the battery output terminal in series with a 10 ohm resistor, so as not to burn out the LED with excessive current).

This method can only test a single LED, to test 3 series LEDs, add 4 dry batteries, or use 9V batteries.

3.Inspection of LEDs with aluminum substrates

You can first visually inspect the solder joints between the LED pins and the aluminum substrate to see if there is false soldering or false soldering.

Low power LEDs

The switching voltage is between and can be tested using the above method.

Hope it helps,

1. The LED power supply should have a constant current, it is best to buy an electronic load to test, or connect 7 side hungry LEDs to test the output current of the power supply? When the LED heats up, the LED

The VF value will be reduced, to see if the output current of the power supply changes, or whether the change range is acceptable, it is best to find some LEDs with different VF values to test, because the VF value is more or less during mass production. If there is an electronic load, it is simple, adjust to 20V to see how much the output current is? Jump to 28V to see how much the output current is?

Many power supplies have very small deviations in output current.

2., will the LED light flicker or have a slight flickering.

3.It is the protection function, the indispensable is the open circuit protection, when not connected to any load will the power supply be broken, how much is the output voltage? If the requirements are strict, it is also necessary to test the output short circuit to ensure the return of the operation, and the withstand voltage (high voltage) test.

4. Harmonics, safety, EMI, EMC, PFC, etc.

Generally, ask professionals to do a test rack test, 1-100w can be tested, and any kind of data can be seen, which is much simpler.

LED, chip inspection, 1Temperature.

2.Luminous flux.

3.Color coordinates, color rendering index, etc., these parameters need to be checked by the integrating sphere.

The question you asked was only about whether the LED was lit or not:

1.The LED can be tested by using a constant current power supply (pay attention to the switch impact in the middle of the process, and pay attention to whether the electrical parameters meet the LED driving parameters when the constant current source is debugged).

2.High-power LEDs are generally turned on at the same voltage, and can be tested with 2 dry batteries in series (note: current limit, it is best to connect the battery output with a 10 ohm resistor to avoid excessive current and burn out the LED) This method can only test a single LED to test 3 series LEDs to add 4 dry batteries or use 9V batteries.

3.To inspect the LED with aluminum substrate, you can first visually inspect the solder joints between the LED pins and the aluminum substrate to see if there is false soldering or false soldering.

The low power LED opening voltage is between and can be tested by the above method.

Hope it helps,

Wouldn't it be over if you try it with a lamp bead?

Precautions that should be paid attention to when testing the withstand voltage of LED lamps1

Precautions for the high-voltage problem of Qingshan aluminum substrate for installing light source: l The light source should not be too close to the edge, and the light source pad should be farther away from the edge, which should not be less than 2mm; l Aluminum-based plates should be selected well, which can withstand high pressure and are non-isolated); l The wiring wire diameter on the aluminum substrate can be larger, 1-2mm; (i.e.: 50 80mil lead through hole punch high voltage problem l.)

Note that the size of the vias is consistent with the light cup; l

Pay attention to removing burrs around the perimeter of the via; l

Add via insulating sleeves; 3.

High voltage problems with power supply drives

Install the fixed power supply driver board correctly; l

Ensure that the drive is absolutely insulated from the lamp cup body, and the imitation chain can be added with thermally conductive insulating paper; l Correct potting; 4.

Standardization of locating holes

Correct positioning to ensure that the aluminum substrate corresponds to the hole position of the lamp cup, so that it can be installed fixedly; l Pay attention to the positioning hole and wiring to have enough spacing to prevent the breakdown phenomenon when playing high voltage due to too small spacing;