Analog, compact and economical solution for the compensation of implantable piezoresistive blood pressure sensors for wireless medicalmonitoring

International audienceThis article presents an analog method of compensation forthermal drifts of implantable piezoresistive blood pressure sensors usedin wireless medical monitoring. A PNP transistor-based circuit in parallelwith a variable resistor is used. This circuit is in series with thepressure probe constituted of four piezoresistors in Wheatstone bridge.This analog method is effective in reducing the thermal drift of thesensor and also has a low cost and consumption. The thermal drift of thesensor before compensation is 9.55 mmHg over the temperature range [34°C -39°C] with the pressure of 300 mmHg and after compensation, the drift isreduced to 2.5 mmHg. This method has been validated with 3 pressure levels(0, 100, 200 and 300 mmHg)