Two-terminal voltage regulator with current-balancing current mirror

摘要

A voltage regulator comprises first and second bipolar transistors operating at different current densities; a resistor is connected between their bases across which &Dgr;VBE appears. A third bipolar transistor is connected such that the voltages at the bases of the first and third transistors are equal or differ by a PTAT amount. A current mirror is arranged to balance the collector current of one of the second and third transistors with an image of the collector current of the first transistor when the output node is at a unique operating point. The operating point includes both PTAT and CTAT components, the ratio of which can be established such that the operating point has a desired temperature characteristic. A transistor connected to the output node and driven by the output of the current mirror regulates the output voltage by negative feedback.