CMOS bandgap voltage reference apparatus and method

摘要

An improved CMOS bandgap voltage reference in which a magnified current derived from a thermal voltage reference produces a voltage drop across a resistor. The resistor in turn couples to a single bipolar transistor which is part of the thermal voltage reference. The bandgap voltage is the sum of the voltage across the resistor and the voltage across the bipolar transistor. In addition, the immunity of a bandgap voltage reference to variations in power supply variations is improved by having a differential amplifier sense the voltages at the control current input and the output of a current mirror in the thermal voltage reference portion of the bandgap voltage reference and adjusting the power supply voltage to the thermal voltage reference until the sensed voltages are substantially the same.