Abstract: A circuit for use in respiration type apparatus using a piezoresistive transducer and wherein the temperature effects on system stabilization are minimized and system initialization times are reduced. The circuit comprises a differential sensor amplifier response to the output of the piezoresistive transducer, a dc negative feedback circuit connected to the output of the differential amplifier, an initialization circuit for reducing the initialization time of the circuit, a diode clamp and voltage follower for clamping the voltage output and a voltage comparator for tracking the circuit operating point and switching its output state when a sudden voltage change caused by a patient breath is detected.

Abstract: A circuit for use in respiration type apparatus using a piezoresistive transducer and wherein the temperature effects on system stabilization are minimized. In addition, means are provided to reduce system initialization times. The circuit comprises a differential sensor amplifier response to the output of the piezoresistive transducer, a dc negative feedback circuit connected to the output of the differential amplifier, means for reducing the initialization time of the circuit, circuit means for clamping the voltage output and a voltage comparator for tracking the circuit operating point and switching its output state when a sudden voltage change caused by a patient breath is detected.