ADC with independant GND and Vref

[flotulopex]

Hello,

I'm wondering if it is possible to implement an ADC knowing the analog input has no connection to the PIC's VDD & VSS.

Is this possible?

[aratti]

Is doable using a galvanic isolator.

Cheers

Al.

[flotulopex]

You mean something like a DC-DC converter?

[aratti]

No! Something like the Texas component slyt211. But there are several others doing the same job.

Cheers

Al.

[flotulopex]

...but, the SLYT211 is a (miniature) DC-DC converter or am I missing something?

[Acetronics2]

Much simpler would be an external V/F converter that can be close to the source ( LM331 as an oldie ! ) http://www12.fairchildsemi.com/ds/KA/KA331.pdf then an opto-coupler :
you then just have to measure the incoming frequency ...

Alain

[aratti]

It is a galvanic isolator. It is also a DC-DC converter but this is just semantic. You need primarely a galvanic isolation.

Alain suggestion to use a voltage to frequency converter, is an interesting and cheap approch!

Cheers

Al.

[flotulopex]

Thanks for all the suggestions.

I never tried a V/F.

I'll give it a try