A voltage-frequency conversion based signal conditioning circuit of silicon piezo-resistive pressure sensor

A temperature self-compensation method based on bridge parameters is proposed for silicon piezo-resistive pressure sensors in this paper. A high-precision processing circuit with differential input and dual parameters output is designed to measure bridge parameters. The circuit is a charge-balanced differential input V-F converter built by simple components. Bridge parameters are calculated by output frequency of different circuit configuration. The circuit eliminates the common mode voltage error and the reference frequency affect by differential input and reference resistance respectively. The final output frequency is related to the quantity to be measured and the reference resistor. It is confirmed by experiment that the measured accuracy of the bridge resistors can reach 0.0068% and the whole pressure sensors' precise is 0.039% after compensation, which demonstrates that this method can improve the measurement precision by one order of magnitude.