Rejection of Power Supply Noise in Wheatstone Bridges : Application to Piezoresistive MEMS
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This paper deals with the design of MEMS using piezoresistivity as transduction principle. It is demonstrated that when the sensor topology doesn't allow a perfect matching of strain gauges, the resolution is limited by the ability of the conditioning circuit (typically a Wheatstone bridge) to reject power supply noise. As this ability is strongly reduced when an offset voltage is present at the output of the bridge, the proposed architecture implements a feedback loop to control MOS transistors inserted in the Wheatstone bridge to compensate resistor mismatches. This feedback exhibits a very good offset cancellation and therefore a better resolution is achieved.
Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838)
Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838)