So I have two same DC/DC step down converters and I'd like to have a green LED driven with the converters' open drain PGOOD signals. The signal is active-high and the LED should be on, when the power is okay and off, when not.
So I came up with this design:
In the converter's datasheet they use a 100k pull-up for PGOOD. I only used a smaller one because I was simulating this circuit in LTSpice and got too small current through the LED.
So when the power isn't okay, the PGOOD is connected to GND and the converters should sink current and the NPN won't conduct - the LED should be off.
And when the power is okay, the PGOOD is Hi-Z so the NPN will conduct and the LED should be on.
Will this work as expected? And if yes, is the design done optimally?