ISOLATED DIGITAL-TO-ANALOG CONVERTER

摘要

A digital-to-analog converter employing a pair of operational amplifiers connected in a balanced differential configuration to supply an analog output to a two-terminal load. The data and power inputs are isolated from the converter by isolation couplers. Each bit of binary data is sensed at the summing junction of each amplifier by means of a pair of balanced resistors which are switched in accordance with the binary signal. Each set of balanced resistors so sensed is in parallel with the other sets between the summing junctions. The balanced differential configuration enables either terminal at the two-terminal load to be at ground reference potential without deteriorating the common-mode rejection capability of the circuit, thereby eliminating the effect of voltages existing between the ground reference at the load and the ground reference at the binary and power input terminals of the converter.