Study and application of bridge circuit based on ratio method

Abstract A new high-precision bridge circuit based on the ratio method is proposed to solve the requirements of high-precision resistance measurement for resistive sensors. The bridge circuit based on the ratio method of the ADC’s digital output is the ratio of the ADC’s analog input voltage and reference voltage, using unbalanced bridge output which is amplified as the analog input of ADC, also using differential voltage of another bridge arm of the same side as the reference voltage of ADC, after analog-digital conversion the ADC’s digital output as the system output. Achieving the resistance signal and the output of the bridge circuit has a strictly linear relationship, overcoming the supply voltage fluctuations has a great impact on the resistance measurement results, and eliminating the system’s zero drift and temperature drift is reached, so the bridge circuit has a better high-precision performance of resistance measurement.