Current Sensor

[sfink06]

Trying to interface a current to voltage transducer to an ADC. My question is, When the voltage output of the sensor goes negative (I'm reversing the current through the sensor with a PIC and an H-bridge,) will this damage the ADC? If so, how can I make the voltage always positive (without multiplexing an inverter.)

 

[Electronworks]

I think I understand what your circuit is doing....

If the output of your I to V converter remains within the input spec of the ADC then you should be OK. Most ADCs accept inputs only within their supply range, although you can get some that run on 0-5V, but accept +/-10V input signals. This is done by using resistors inside the ADC to reduce the input voltage and level shifting using an op amp (again inside the ADC).

If your voltage from your sensor might go outside the common mode range of the ADC, then you can always add a level shifter around an external op amp.

 

[sfink06]

thanks, looks like the level shifter is what I need to convert the -/+ 3V from the current sensor to 0-Vref (Vref being the reference voltage of the ADC) to sample it.