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I have got a LED fixture with a flickering problem. As I am unable to check the output due to lack of equipment I would like to research and gather some information first. The switch used is not dimmed, it is an usual mains switch.

It blinks at around 2 Hz. LED driver is based on BP3106 chip with a similar circuit as per image (taken from datasheet):

LED driver circuit based on BP3106 chip

Visual inspection does not show any damage on output capacitors or any other part. I must say that this lamp worked at least 1 year before it started failing. See photo below:

Overall circuit

I presume it is a problem with output capacitors but due to lack of experience and equipment I cannot find anything. I could try to check at work in a week time but meanwhile may I get some enlightment regarding this? What part(s) is/are more likely to fail after a year? Bear on mind this looks like a generic LED driver (no manufacturer information attached on housing). Specs are:

LED Driver: Constant current, Model LF02/25-30*1W, input 180-260V 50/60Hz, output 285-315mA, 75-100V.

Lamp: 5x 12V/5W connected in series.

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  • \$\begingroup\$ I'd be suspicious of the capacitor across the chip's Vcc and also the high value resistor that feeds it. \$\endgroup\$ – Andy aka Dec 30 '15 at 14:15
  • \$\begingroup\$ I had similar case with less powerful version also based on BP3106. Here is the datasheet in English. bpsemi.com/uploads/file/20161124180712_351.pdf The drivers from this family provide 0.25-0.28A and range from 3to12V to 75to 135V (depending on power rating). I also established that the LED consumes when fed from a lab power supply at rated 12V just 10mA, and lights accordingly. I tried higher voltage LED chain (4 parallel strings each 7 in series) and it still blinked. I also tried resistive load in increments of 5 Ohm from (5 to 40) - still blinking \$\endgroup\$ – Petkan Feb 2 '18 at 14:34
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According to the specs and the lamp data you provided, you may be experiencing a UV protection in your circuit. The spec say that the output voltage should lay between 75V and 100V and you wrote you are connecting 5x12V LEDs in series. Therefore, you have a total of about 60V load into the driver. Most probably the circuit starts, detects the under voltage, turns off and tries to re-start again. This may be the reason for your 2Hz flicker. Try adding more LEDs in series to reach the minimum required load voltage (75V). PS. Could you provide a link to the datasheet in English?

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  • \$\begingroup\$ I checked the LED strip, 2 LED chips were faulty (a black point was observed on them). Unfortunately I missed the pictures. LED strip was replaced and module worked properly. Many thanks for the previous answers! \$\endgroup\$ – Greg M Jan 6 '16 at 18:53
  • \$\begingroup\$ It turned to be the load (LED strip) rather than the module itself. Sadly no, I found this datasheet and I had to sort it out in Chinese. \$\endgroup\$ – Greg M Jan 6 '16 at 18:58

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