A Bandgap Reference Circuit with High Power Supply Rejection Ratio and Self-starting Circuit

Abstract

The invention discloses a band-gap reference circuit with a high power supply rejection ratio characteristic and an automatic starting circuit. The band-gap reference circuit comprises a band-gap reference circuit body, a current circuit, a feedback circuit and the starting circuit; the current circuit is used for increasing a resistance value between a direct-current power supply VDD and the direct-current input end of a band-gap reference core circuit and reducing interference of the direct-current power supply VDD to voltage Vd of the direct-current input end of the band-gap reference circuit, therefore, the power supply rejection ratio is increased, and the circuit stability is improved; when the band-gap reference circuit body is in a zero-current state, the starting circuit starts to work, the band-gap reference circuit body deviates from the zero-current state, the band-gap reference circuit body feeds state information back to the starting circuit through the feedback circuit simultaneously, and when the band-gap reference circuit body works normally, the starting circuit stops working.

Description

technical field [0001] The invention relates to the field of bandgap reference circuits, in particular to a bandgap reference circuit with high power supply rejection ratio and self-starting circuit. Background technique [0002] The basic principle of the bandgap reference circuit is to add two voltages with opposite temperature coefficients with appropriate weights, and finally obtain a reference voltage with zero temperature coefficient. For example, the voltage V+ has a positive temperature coefficient, and the voltage V- has a negative temperature coefficient. There are appropriate weights α and β, satisfying This results in a reference voltage with zero temperature coefficient, the expression of the reference voltage is V ref =αV + +βV - . [0003] A bipolar junction transistor (BJT) has the following two characteristics: [0004] 1. The base-emitter voltage V of the bipolar transistor BE Voltage is inversely proportional to absolute temperature; [0005] 2. Un...

AI Technical Summary

Problems solved by technology

The current start-up circuit generally forces the controlled circuit to deviate from the zero-current state by providing a start-up voltage, but this start-up method is unstable, and the controlled circuit may return to the zero-current state and fail to start normally.

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