Wearable wrist electronic blood pressure monitor sensor circuit design

　　Circuit principle: This circuit uses BP01 pressure sensor and MAX4472 operational amplifier. BP01 pressure sensor is specially designed for blood pressure detection and is mainly used in portable electronic sphygmomanometers. It uses precision thick film ceramic chip and nylon plastic package, with high linearity, low noise and low external stress. It uses internal calibration and temperature compensation to improve the measurement accuracy, stability and repeatability. Within the full range, the accuracy is ±1% and the zero offset is no more than ±300μV. MAX4472 is a low-power amplifier chip integrated with four operational amplifiers from MAXIM. In this system, the internal integrated operational amplifier A is connected to the constant current source to provide a constant current for the pressure sensor. The operational amplifier B, operational amplifier C and operational amplifier D form a differential input and single-ended output amplifier circuit, which is directly input into ADC0 to monitor the DC component of blood pressure.

　　Blood pressure sensor circuit