Analog, compact and economical solution for the compensation of implantable piezoresistive blood pressure sensors for wireless medical monitoring
Abstract
This article presents an analog method of compensation for
thermal drifts of implantable piezoresistive blood pressure sensors used
in wireless medical monitoring. A PNP transistor-based circuit in parallel
with a variable resistor is used. This circuit is in series with the
pressure probe constituted of four piezoresistors in Wheatstone bridge.
This analog method is effective in reducing the thermal drift of the
sensor and also has a low cost and consumption. The thermal drift of the
sensor 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 is
reduced to 2.5 mmHg. This method has been validated with 3 pressure levels
(0, 100, 200 and 300 mmHg).