A Micro Power Capacitive Sensor Readout Channel Based on the Chopper Modulation Technique

A low power capacitance to voltage converter, specifically designed for integrated sensors, is presented. The circuit is based on a fully differential impedance meter driven by a triangular wave form. Synchronous demodulation allows effective reduction of low frequency noise and device mismatch effects. The results of simulations performed on a prototype, designed using the BCD6s process of STMicroelectronics, are presented.