Tool/software:
Hello
We have been using this circuit for 7 years, roughly 7,000 boards with no issues. Suddenly we have had several boards fail in the field where D1 gets destroyed. We also had only 2 boards where U1 was damaged. Ihave been trying to duplicate the issue with no luck. It drives an LED panel rated for 21.5 volts, 180ma.
Here is what I tried:
Running the output at 500ma, circuit worked fine-no issues
Running the circuit from 5 volts to 28 volts input, normal input voltage is 12 volts. No issues.
Short the output. The current sense resistor R1 failed. After replacing the current sense resistor, the circuit worked fine.
Ran in a chamber at 70 Deg C with no issues.
Any suggestions what may be destroying D1?
Thank you for your help.
Greg Detuzzi
