Enable DCDC with PowerGood

Thread Starter

dman92

Joined Apr 30, 2021
1
Hi!!

I'm working with a BuckRegulatro from Vicor, PI3423-00-LGIZ . And I want to use the PowerGood signal to disable another DCDC ( with an ON(3.3V) or OFF(GND) signal). The question is that the PowerGood of the PI3423 is HighImpedance (operating and no stable) or Voltage output (when the converter has a correct Output).

Any cool solution for this? Maybe a pull-down and an inversor can work but I think is not the way.

Thanks!!!!
 

andrewmm

Joined Feb 25, 2011
1,470
power good outputs are normaly open collector,
I guess you have measured this, read the data sheet.

For open collector, what you need to do is put a pull up resistor to the Vcc.
then when power is bad, it will be at Vcc, when power good, it will be at gnd.

Again most DCDC , have an enable input that is active low,
so in that case, the Vcc is the input voltage of the second DCDC,
and the power good just connects to the ~EN input of the following DCDC

If the voltages of the second dcdc enable input are up the other way, or need voltage translating, then you need to use a fet / transitor to interface the Power good,
 
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