A SIMPLE ACCURATE BRIDGE-TRANSDUCER INTERFACE WITH CONTINUOUS AUTOCALIBRATION

This paper presents a one-chip simple and accurate transducer interfac e for resistive bridges. A key part of this interface is formed by a n ovel dynamic voltage divider, In this divider the bridge supply voltag e is measured for reference purposes in small parts (piece-wise measur ement) which are within the range of the bridge output voltage. The us e of an autocalibration technique, the three-signal method, eliminates influence of linear parameters and errors. Moreover, the effects of t he nonidealities of the applied switches are also eliminated. The circ uit has been realized in a 3 mu m BiCMOS process and shows an uncertai nty of only 10 mu V for a bridge supply voltage of 5 V.