Thermal drift compensation of piezoresistive implantable blood pressure sensors with low cost analog solutions

Abstract

This paper reports on three low cost analog solutions for compensating thermal drift of piezoresistive implantable blood pressure sensors. Body temperature variations distort blood pressure measurements due to pyroelectric effect. It's therefore indispensable to compensate thermal drift of the used sensors. Compensating techniques should be low cost, compact and have low consumption. We present in the paper three thermal drift compensation techniques respectively based on a current source LM334, negative temperature coefficient thermistors and a combination of negative temperature coefficient thermistors and a current source LM334. The first compensation technique gives a lower thermal drift coefficient (V out /°C) than the two last techniques over a large pressure range. The first and the second technique can cancel thermal drift over different pressure ranges.