Flashing on product COB LED

zihuatanejo · Aug 20, 2013

Hi Guys,
I have a product which works with 15x4 watt constant current driver and it has COB LED 4 pieces , when i start it up after a while it starts to make flash , i realized driver warms up then this flashing starts on product LEDs is ok but i m not sure whether the reason bcz of warming on driver, any idea for solving this problem? does product need more stronger heat sink part to cool? or ?
thanx in advance for replies..

evilc66 · Aug 20, 2013

The blinking is caused by the driver. It's possible that a capacitor has failed, causing the blinking. It would explain why it only starts blinking after it warms up a little.

zihuatanejo · Aug 21, 2013

thank you for early answer , you think it s caused by capasitor after warming up , i cannot open driver to see, it has slicon pressed,
to solve problem should it has more heat sink system or capacitor should better one?
thanx

Steve K · Aug 21, 2013

The driver may have a thermal shutdown mode, to protect itself if it gets too warm. You might try adding heatsinking for the driver, adding some cooling air, or putting it in the refrigerator (just to test the hypothesis).
If it is getting too hot to touch, then this is definitely a possibility.

evilc66 · Aug 21, 2013

Try what Steve K said first, but I'd be willing to bet it's the capacitor, and not a thermal shutdown issue. The thermal shutdown would turn the LED off (or maybe just reduced output) for a lot longer than a blink to get the driver chip temperature below it's thermal threshold. If the capacitor is at fault, then your only option is to replace the driver.

WeLight · Aug 22, 2013

what is the vf of leds(how are they wired) and capacity of the driver, flickering is often a poor load match between driver and leds and can become apparent after settling time, also cheap drivers have typically poor harmonics and will emit nasty transients( not saying, just asking)

zihuatanejo · Aug 26, 2013

thanks you guys,
i also realized that when i even put new driver , i mean i change driver which caused to flash, after too hot the new one starts making flash,
probably we need the firm to change its capacitor

best regards

SemiMan · Aug 31, 2013

Highly unlikely its the capacitor but it could be any part of the circuit that is going out of spec with the least likely being the output capacitor. It could be almost anything and we are just guessing at this point.

Sent from my Nexus 4 using Tapatalk 4

Julian Holtz · Sep 27, 2013

I had the same thing happen after several months of operating a driver at too high heat.

OP, what you have to do is either change the driver for a more powerful one, or make the current version run cooler by allowing more airflow.

Less heat to the driver components, this is what you have to aim for.

Flashing on product COB LED

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