The LED drive power supply is to convert the power supply to a specific voltage current to drive the LED light -emitting power converter. Generally, the input of LED drive power includes high -voltage frequency AC (that is, city power), low voltage DC, high voltage, low voltage high, high voltage highFrequent communication (such as the output of electronic transformers) and so on.The output of the LED -drive power supply is mostly the constant current source that can change the voltage with the changes in the value reduction of the LED forward voltage.
LED drive power brand
Domestic LED -driven Power Brand Rankings: 1. Taiwan Mingwei.2. Dongguan UEElectronic.3. Delta Electronics.4. Hangzhou Yingfei.5. Shenzhen Maoshuo.6. Shenzhen Ruigu.7. Thaiheng Electronics.8. Guanjin Electronics.9. Jingchen Electronics.10. Jinxing Technology.Global LED -driven Power Brand Ranking: 1. Texas Instruments (TI), USA.2. National Semiconductor (NS).3. Maxim.4. Analogictech.5. Linear.6. NXP (NXP) in the Netherlands.7. China Fuelectronic.8. Infineon.9. Toshiba, Japan.10. OnSemi.
LED drive power principle
The front voltage drop (VF) and the (IF) relationship curve of the positive current can be seen from the curve that when the forward voltage exceeds a certain threshold (about 2V), that is, the generally referred toVF is proportional.See the table for the current electrical characteristics of the main ultra -highlighting LED.It can be seen from the table that the highest IF of the current ultra -highlighted LED can reach 1A, while VF is usually 2 ~ 4V.Because LED optical characteristics are usually described as a function of the current, not the function of the voltage, the relationship curve of the optical flux (φV) and IF, the use of the constant current source can better control the brightness.In addition, the range of the forward voltage drop of LED is relatively large (up to 1V above 1V), and from the VF-IF curve in the figure above, it can be seen that the slight changes in VF will cause a largeBig change.Therefore, the use of constant voltage source drivers cannot ensure the consistency of LED brightness and affect the reliability, life and light aging of LED.Therefore, ultra -highlighted LEDs are usually driven by constant current source.
LED driver power design entry
One of the techniques, do not use bipolar power devices because bipolar power devices are cheaper than MOSFET, generally about 2 cents, so some designers use bipolar power devices in order to reduce LED driver costs.The reliability of the circuit, because with the increase of the temperature of the LED drive circuit board, the effective working scope of bipolar devices will be quickly reduced, which will cause the device to fail when the temperature rises and affect the reliability of the LED lamp. The correct approach is to needSelect MOSFET devices, the service life of MOSFET devices is far longer than bipolar devices.The second, MOSFETs resistance to MOSFET should not be lower than 700V to 600V, and many think that the input voltage of LED lamps is generally 220V, so the resistance voltage is 600V, but many times the circuit voltage will reach 340V.At the time of surge, the 600V MOSFET is easily penetrated, which affects the life of LED lamps. In fact, using 600VMOSFET may save some costs, but the price of the entire circuit board is paid.It is best to choose MOSFET with more than 700V resistance.
LED driver power repair
The power supply is difficult to repair and succeed without accessories. It also requires a certain amount of technology. If you really want to repair it, you must string a 5W light bulb for insurance.

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