Tool/software:
Hello,
When I plug in my board to AC power, I get regular but slow flickers from my output power LEDs, but then when I unplug the device, it clicks and then VDD is shorted to ground next time I plug the device in. Any thoughts on how this could happen?
Input is 120VAC, output requirements are 12VDC @2A.
The current load includes 5V DC-DC, 3V3 DC-DC, 3 LEDs, and an ESP32. There will be more load when in use, but that's about all at boot.
Lucas,
When you unplugged the AC, what clicked? What is your AC input voltage? 110VAC?
The schematic seems fine with me. I'd increase R6, R10 and R15 as shown below and also add a clamping diode on VDD pin to protect VDD.
It is always a good idea to share some waveforms so we can understand what happened. If only the IC is broken, you could replace it and repeat the process while monitoring the Vout, VDD, switching node and Vin.
As far as the slow flicker of the LED, it means that Vout is not stable and has large ripple. Scope the Vout first.
What is your total power loading upon power up?
