Patent ID: 7253599
Filing Date: 2007-08-07
Classification: G05F

Abstract:
1. A bandgap reference circuit, comprising: a first amplifier; a second amplifier, having an input terminal coupled to an input terminal of said first amplifier; a first bipolar junction transistor; a second bipolar junction transistor, having an emitter with an emitter area equal to an integer multiple of an emitter area of an emitter of said first bipolar junction transistor; a first metal oxide semiconductor, having a drain thereof electrically connected to said first bipolar junction transistor; a second metal oxide semiconductor, having a drain thereof electrically connected to said second bipolar junction transistor; a third metal oxide semiconductor; a fourth metal oxide semiconductor, having a gate thereof electrically connected to an output terminal of said second amplifier; and a fifth metal oxide semiconductor, having a gate thereof electrically connected to said output terminal of said second amplifier, and a drain of said fifth metal oxide semiconductor connected to a drain of said third metal oxide semiconductor; thereby the respective sources of said first, second, third, fourth and fifth metal oxide semiconductors are jointly and electrically connected to a source of supplied power and provide equal drain currents and a bandgap reference circuit outputs a stable startup voltage that has a low sensitivity to a change of temperature and a change of supplied voltage.