I've been looking around for something like this for a while. Have a project that has 8 internal modules, and a controller module, all with a common ground across a signal cable (16 pin 30AWG, 8 are ground).
Each module has separate power and ground inputs, but because of the common ground in the signal cable, if one of the power grounds that goes to a module fails in some way, current will return through the signal ground, which I definitely don't want. (This is assuming that we use a single PSU to power the whole thing.)
The solution of course is to use an isolated PSU for each module, so that it only sinks the current that it sources. This way, if we have a power ground connection fail, the module itself will stop working, but it wont damage the signal conductors.
However, I can't seem to find an off-the-shelf PSU that allows for analog voltage control of the output voltage. Our target price is ~$40-80 per supply, each one rated for 15V at around 10A. I want analog voltage control, because the modules need to have the same output voltage (within 100mV or so), and I could pretty easily design a control circuit that would do this.
I've run across this one:
http://www.powergatellc.com/Featured-Products/1200-watt-modular-power-supply-in-ultra-miniature-6-x-6-x-16-footprint.htmlWhich fits our needs, in terms of analog control over output voltage, but Powergate is mandating NCNR terms, and I don't want to commit to something without at least trying it first.
Anyone know of another solution out there? Is there some way to provide the protection I need with a single PSU?
I was thinking that a low-side and high-side current shunt resistor on each power output pair, with an MCU for control might do the trick. If the voltage drops across the shunt show a large discrepancy, then a fault has occurred, and we could shut off power for that particular output. What do you guys think?