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Why do LED lights tend to flicker sometimes and how to slove it?

Views:534     Author:Site Editor     Publish Time: 2019-11-04      Origin:Site

1): the LED lamp bead does not match the LED driving power supply. Normally, a single full 1W lamp bead bears the current of 280-300ma and the voltage of 3.0-3.4v. If the lamp bead chip is not full power, it will cause the stroboscopic phenomenon of the light source. If the current is too high, the lamp bead will be on and off as soon as it can't bear it. The serious phenomenon will burn off the gold wire or copper wire inside the lamp bead, resulting in the lamp bead not being on.

2): maybe the driving power supply is broken. As long as you replace it with another good driving power supply, it will not flash.

3): if the drive has the over temperature protection function, and the heat dissipation performance of the lamp material cannot meet the requirements, the drive over temperature protection will flash and go out when it starts to work. For example, if the 20W floodlight shell is used to assemble the 30W lamp, it will be like this if the heat dissipation work is not done well.

4): if the outdoor lamps also have the phenomenon of stroboscopic on and off, it is that the lamps are flooded. The result is that it doesn't flash. The lamp bead and driver are broken. If the driver is waterproof, it is just to break the lamp bead and replace the light source.


How to deal with LED flashing?


1. In off-line low-power LED lighting applications, a common power topology is isolated flyback topology. Taking the Greenpoint? Reference design of 8W off-line LED driver in line with the "Energy Star" solid-state lighting standard as an example, since the sine square wave power conversion of flyback regulator does not provide constant energy for the primary bias, the dynamic self powered (DSS) circuit may activate and cause flicker. In order to avoid this problem, it is necessary to make the primary bias discharge in each half cycle. Accordingly, it is necessary to properly select the capacitance and resistance of the bias circuit.


2. Generally, the human eye can sense the flicker of light with a frequency up to 70 Hz, but it will not sense if the frequency is higher than this. Therefore, in the application of LED lighting, if the frequency of pulse signal is lower than 70 Hz, the human eye will feel the flicker. Of course, in specific applications, there are many factors that may cause LED lights to flash.


3. Electromagnetic interference (EMI) filters are required even in LED drive applications that provide good power factor correction and support triac dimming. The transient current caused by triac step will excite the natural resonance of inductance and capacitance in EMI filter. If this resonant characteristic causes the input current to fall below the triac holding current, triac will turn off. After a short time delay, triac is usually turned on again, and the same resonance is excited. During one and a half cycles of the input power waveform, this series of events may be repeated many times, forming a visible LED flash.





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