Patent ID: 7191072
Filing Date: 2007-03-13
Classification: G01D

Abstract:
1. A temperature and pressure measuring circuit comprising: an uncompensated pressure transducer having variable resistive devices between first, second, third, and fourth bridge nodes, the fourth bridge node coupled to a ground; an analog-to-digital (A/D) converter having first and second reference inputs and first and second differential inputs; a reference resistive device between first and second reference nodes, the first reference node coupled to a voltage source, the second reference node coupled to the third bridge node; a first switch adapted to selectively couple the first differential input and one of the first bridge node and the third bridge node; and a second switch adapted to selectively couple the second differential input and one of the second bridge node and the ground; wherein, when the first switch couples the first differential input and the third bridge node and the second switch couples the second differential input and the ground, a bridge voltage is measurable and a bridge resistance is ratiometrically determinable, the bridge resistance employed to calculate a temperature; and wherein, when the first switch couples the first differential input and the first bridge node and the second switch couples the second differential input and the second bridge node, a differential voltage is measurable, the differential voltage employed to calculate a pressure.