Wheatstone bridge amplifier circuit with integrated diagnostic testing

摘要

An amplifier circuit and method of providing diagnostic testing to a Wheatstone bridge amplifier circuit are provided herein. The amplifier circuit includes a balanced circuit such as a Wheatstone bridge employed in a piezoresistive transducer which produces a differential output signal. The amplifier circuit also includes an amplifier having a differential input for amplifying differential input signals. A diagnostic test circuit is coupled between the balanced circuit and the amplifier circuit and includes a pair of resistors with current sources which may be switched in via electronic switches. With the current sources switched in, a known offset voltage is applied across the differential input to the amplifier and the amplifier output is monitored and compared to an initial output signal. By comparing the initial output signal with the test signal, a determination as to the gain and other characteristics of the amplifier circuit can be made.