I’ve made my own boarddesign for a future product i want to use. I used the same schematic as you used for the 12V powersupply of the Chipworkx Dev. System. But i have a little problem after assembling my PCB.

I put 12V in my PCB and i don’t get more then 1.2V out of the supply circuit. Can you tell me what the problem is?

Kind Regards

hi Nick,

First, make sure your diodes are facing the correct way, as wellas any polarised capacitors.

Secondly, if you have an adjustable switchmode ic (i cant check the design atm, im on a train, make sure your resistor values are correct for the voltage divider. If the board is designed for a predertmined voltage - are you sure you dont have an adjustable reg? most power ic’s use a 1.2v reference for voltage matching whick might explain the output you are seeing.

Hi Mark,

Thank you for you’re quick answer. My Diodes and polarised capacitors are facing the correct way. But I found the problem. I use the Micrel MIC4680YM and you use the Micrel MIC4680-5.0YM. So i’m just going to order the right IC first.

Thank you for you’re help.

Ah ha, so you did get an adjustable regulator rather than a constant voltage.

If you can solder fine wires onto the board, you might be able to solder wires directly to it to hook into the adj circuit for the vref. You might need to cut a couple of wires.


I just ordered some new IC’s and now it’s working.

Kind Regards