Patent ID: 9678526
Date: 2017-06-13
CPC Classifications: G05F

Claim:
1. A bandgap reference circuit comprising: a first bipolar transistor, a base and a collector of the first bipolar transistor being connected to each other; a second bipolar transistor, a base and a collector of the second bipolar transistor being connected to each other; a third bipolar transistor having the same conductivity type as that of the first and second bipolar transistors, a base and a collector of the third bipolar transistor being connected to each other; a first current distribution circuit that makes a first current and a second current flow between the collectors and emitters of the first and second bipolar transistors, respectively, the first current corresponding to a first control voltage, the second current being in proportion to the first current; a first NMOS transistor disposed between the first bipolar transistor and the first current distribution circuit, a gate of the first NMOS transistor being supplied with a second control voltage; a second NMOS transistor disposed between the second bipolar transistor and the first current distribution circuit, a gate of the second NMOS transistor being supplied with the second control voltage; a first resistive element disposed between the second NMOS transistor and the second bipolar transistor; a second resistive element disposed between the third bipolar transistor and the first current distribution circuit; a third resistive element disposed in parallel with the second resistive element and the third bipolar transistor; a first operational amplifier that generates the second control voltage according to a drain voltage of the first NMOS transistor and a reference bias voltage; and a second operational amplifier that generates the first control voltage according to a drain voltage of the second NMOS transistor and the reference bias voltage, wherein the first current distribution circuit further makes a third current, in proportion to the first and second currents, flow between the collector and an emitter of the third bipolar transistor, wherein the bandgap reference circuit outputs a voltage at a node on a current path extending from the first current distribution circuit to the second resistive element.