PRECISION CMOS VOLTAGE REFERENCE

摘要

A system provides for a voltage reference having a small temperature coefficient spread. The voltage reference includes a PTAT voltage trimming circuit that accurately trims the CTAT voltage component of the bandgap type voltage reference. The voltage trimming circuit includes two bipolar transistors that are biased by biasing currents to create a specific base-emitter voltage difference at an output. The bias currents can be digitally trimmed by a current digital-to-analog ("DAC") converter. This may result in the ability to trim the voltage reference at a single temperature, without the need to trim at two or more temperatures.