I'm working on something where I use an Arduino talking via I2C to a DAC, an ADC and an RTC and I'm provisioning an I2C isolator and a digital isolator (for digital pins) to provide separation between the two. I'm doing this to prevent blowing up the Arduino if something goes wrong and also just because I want to as part of experimenting/learning.
This only works if both power and ground on sides A and B of the isolators are separate from each other. To complicate matters, if this all works and I encase it then I only want one power cord into the case - something like a 15V wallwart affair. This would, inevitably, tie grounds together and the isolators won't work: not 'won't work in an isolation' sense, but not work at all - I've tried it!
So I'm wondering if I could feed the 15V supply into a 12V regulator and subsequently a 5V regulator for Side B (I need 12V and 5V on that side) and into a 12V DC-DC isolator that outputs 5V for side A which also powers the Arduino.
Something like this Tracopower supply. When I look at this I see that the Vin ground is connected on Side B, but the Vout -Ve is isolated for Side A so it seems like it would do the trick. I thought I'd ask here first before committing to spending money to try it out or indeed if there were other ideas.
My main criteria are:
5V, 1A output
Clean enough to power an Arduino and 5V vin isolator (I could use a supply with a higher ouput voltage and feed through a 5V regulator)
Only 1 main power input. If there's no solution that allows for this, I'd do away with the isolation altogether. In reality it's not really needed.
