Many types of industrial end-equipment employ resistive bridges to sense changes in physical variables such as strain, force, pressure or flow rates. A common industrial application for resistive bridges is precision weigh scales. In this application, weight is translated into a voltage using a resistive bridge embedded in a load cell similar to Figure 1.
Such a 4-wire load cell requires an excitation voltage,
VEXC±, and outputs a differential signal voltage, VSIG±,
proportional to the applied weight. Typically, VSIG± (max) is on the order of tens of millivolts, requiring a low-noise, precision delta-sigma ADC with integrated gain to provide repeatable measurements for such low-level signals.