I'm looking for a way to measure the +/-10A current in/out of a battery using this current sensor (10A variant). It needs a +/-15V supply and outputs +/-4V at it's rated current. I'll assume however that the output ranges from the full -15 to +15V and I'll just use an ADC with enough resolution to get the desired precision at +/-4V.
I think the MCP3425 16-bit ADC (datasheet) should be suitable but I'm not sure how to connect the two. On its differential inputs, it expects +/-2.048v to get the full 16-bit resolution, but the voltage on either pins can't be lower than -0.3V relative to GND.
This means that I can't just scale the +/-15V down to +/-2.048V using a voltage divider and feed it into the pins. I'd have to shift it up first. Maybe another option could be to set the PGA to 8x and scale the voltage to +/-256mV so it won't exceed -0.3V.
I'd also like to 'average' the output of the current sensor before feeding it into the ADC. The plan is to take 10 readings/s so I'd like each reading to approximately represent the average current over the last 100ms. I read about true RMS to voltage ICs but these are quite expensive and probably overkill. Can I just use an RC filter for this? If so, where exactly should I put it and which R and C values should I use? The switching frequency of the battery's current will probably be around 100kHz.