Constant current source circuit with band-gap reference function

Abstract

The invention relates to a constant current source circuit with a band-gap reference function, comprising a band-gap reference core unit, a band-gap reference bias unit and a constant current source output unit, wherein the band-gap reference bias unit is used for providing bias current to a band-gap reference core; the band-bap reference core unit is used for providing band-gap reference voltage with a certain temperature coefficient to the constant current source output unit; and by combining a fuse wire trimming structure of the constant current source output unit, current of a whole constant current source branch can be adjusted. Through adjusting the temperature coefficient of the band-gap reference voltage to be matched with a temperature coefficient of resistance of the constant current source output unit, constant current source current which is insensitive to supply voltage and temperature is obtained. The constant current source circuit is applied to linear power supplies with micro power consumption and low voltage difference to ensure that the temperature coefficient of static current of the linear power supplies with low voltage difference is less than 50 ppm / DEG C, and the rejection ratio of the supply voltage is greater than 60 dB. The constant current source circuit can be applied to the field of linear power supplies with micro power consumption and low voltage difference.

Description

technical field [0001] The invention relates to a constant current source circuit, in particular to a constant current source circuit with the function of a bandgap reference source, which is directly applied to the field of micro-power consumption and low-dropout linear power supplies. Background technique [0002] The constant current source circuit is the core unit of the low dropout linear power supply, especially the constant current source circuit with bandgap reference performance, which is applied to the micro power consumption low dropout linear power supply. figure 1 It is a circuit block diagram of a traditional micro-power low-dropout linear power supply, which consists of bandgap reference source, error amplifier, PMOS regulator, constant current source circuit, over / undervoltage protection, over / undercurrent protection and other unit circuits. The constant current source circuit provides bias current for the error amplifier, bandgap reference source, over / under...

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a constant current source circuit with the function of a bandgap reference source to overcome the problems of sensitivity to power supply voltage changes and large temperature coefficients in traditional constant current source circuits, so as to meet the high requirements of micro-power consumption and low-dropout linear power supplies. performance requirements

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