Isolate Neutral from digital Ground

Thread Starter

JayMith

Joined Mar 11, 2022
5
Hello,

I am designing a controller board for in circuit testing(ICT) of test-PCBs. The test-PCB will have a non-isolated AC-DC converter to get 12V DC(ground of this is directly connected to neutral) that will then be stepped down to 3.3V using LDO. The power for the controller board will be from a 12V adapter(from isolated AC-DC converter inside adapter). I have a test that measures 12V on the test-PCB. My worry is that here I cannot short the neutral on the test-PCB to the digital ground on the controller board. How to go about it?
 

Ian0

Joined Aug 7, 2020
6,711
Is the test pcb already designed?
if not, add a voltage supervisor circuit, which outputs a logic signal if the 12V is OK.
Otherwise you need an isolated a/d convertor (Texas and Analog Davices make them), but the isolated A/D will need to be powered from both the isolated and the non-isolated supply.
 

Thread Starter

JayMith

Joined Mar 11, 2022
5
PCB is already designed. I feel I have left with only one choice something like a isolation amplifier for voltage measurement. But I have not come across parts that take AC neutral as one of its GND. Could you suggest any?
 
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