Patent ID: 8159206

Claim:
A voltage regulator circuit, comprising: an output node; a supply voltage; a first bipolar transistor (Q 1 ); a second bipolar transistor (Q 2 ), said first and second bipolar transistors arranged to operate at different current densities; a first resistance R 1 connected between the collector and base of said first bipolar transistor, the collector of said first bipolar transistor also connected to the base of said second bipolar transistor such that the difference between the base-emitter voltages of said first and second bipolar transistors (ΔVBE) appears across said first resistance; a third bipolar transistor (Q 3 ) connected to conduct a current which varies with the voltage at the base of said first bipolar transistor, the voltages at the bases of said first and third bipolar transistors being equal or differing by a voltage which is proportional-to-absolute-temperature (PTAT); a current mirror referenced to said supply voltage, connected between the collectors of said second and third bipolar transistors, and arranged to balance the collector current of one of said second and third bipolar transistors with an image of the collector current of said first bipolar transistor when said output node is at a unique operating point; and a feedback transistor which is connected between said supply voltage and said output node, said voltage regulator circuit arranged such that said feedback transistor provides current to the bases of each of said first, second and third bipolar transistors and to said output node and is driven by the output of said current mirror so as to regulate the voltage at said output node by negative feedback.