Pressure sensors interfacing circuit with digital output

An interfacing circuit for piezoresistive pressure sensors based on a generalised current mode building block, termed operational floating amplifier (OFA), is presented. Main advantages of the proposed circuit are the very simple configuration using two OFAs and only one piezoresistor, and the highly linear frequency output, which is directly proportional to relative piezoresistance variation. Experimental results are included to demonstrate its performance