Bandgap reference circuit

摘要

A bandgap reference circuit incorporates first, second, and third current sources, first and second operational amplifiers, first and second bipolar transistors, a feedback device, a voltage divider, and a first resistor. The voltage divider divides a voltage difference between the third current source and the base of the second bipolar transistor to provide a reference voltage whose value is smaller than a silicon bandgap voltage.

主权项

1. A bandgap reference circuit, comprising:
a first amplifier having a first input, a second input and a first output; a second amplifier having a third input, a fourth input and a second output; a first current source coupled between a power supply node and the first input of the first amplifier; a second current source coupled between the power supply node and the second input of the first amplifier; a third current source coupled between the power supply node and the third input of the second amplifier; a first bipolar transistor having a base, an emitter coupled to the first current source, and a collector coupled to a ground voltage; a second bipolar transistor having a base coupled to the base of the first bipolar transistor, an emitter, and a collector coupled to the ground voltage; a first resistor coupled between the second current source and the emitter of the second bipolar transistor; a feedback device coupled between the third current source and the base of the second bipolar transistor, the feedback device being controlled by the second output of the second amplifier; and a voltage divider configured to divide a voltage difference between the third current source and the base of the second bipolar transistor to provide a reference voltage; wherein the fourth input of the second amplifier is couple to one of the first input of the first amplifier and the second input of the first amplifier.