Hi All,
We are using a blue LED in our design From Rohm and We have been having premature LED failure within a month from the field. I am not sure what’s going with the LED driver. I have attached the driver circuit/datasheet for your review and help would be greatly appreciated.
Thanks,
WJ
What voltage is being delivered @ the output? Also: what is the rated range for the LED that you are using?
You’re over driving the LED and that is reducing its useful life.
R59 needs to be 168 ohoms or larger to reduce the amount of current passing through the LED.
Yes, overdriving the LED.
Keep it under 20 milliamps and they’ll live long, emittful lives.
Hi, I am working on a design that uses a relay to control LED lights. The schematic shows +12VDC LEDs connected to the (+) terminals, while the other end (-) of the terminal is connected to both an opto-coupler and the relay, which then feeds into the MCU. Regardless of whether the relay is on or off, I only see a high signal at the opto-coupler output. I’m not sure what the issue is with the attached circuit. Can anyone help me identify and rectify the problem? I have already designed a PCB with this circuit and would like to avoid repeating the same mistake in the new build. Thank you
Can you post your schematic?
