Universal Interfacing Circuit for Resistive-Bridge Sensors

A universal interfacing circuit for resistive-bridge sensing elements and bridge-output-to-frequency and/or duty cycle converters is described in this paper. It is based on a simple, cost effective three-point measuring technique and does not require any additional active components. The designed IC has been realized in a standard CMOS technology as a low power Application Specific Integrated Processor (ASIP). The active supply current at operating voltage +4.5 V and clock frequency 20 MHz is not more than 9.5 mA The circuit has been tested with a strain gauges bridge emulator and differential pressure resistive bridge sensor SX30GD2.