Band-gap reference circuit

Abstract

The invention relates to a band-gap reference circuit. The band-gap reference circuit comprises a reference voltage source VREF, a band-gap core circuit, a negative feedback circuit and a starting circuit, wherein gate voltage V_REG is stretched by the reference voltage source VREF so that internal voltage pre-stabilization can be achieved, an internal voltage pre-stabilizing circuit is formed, the band-gap core circuit is provided with an automatic biasing cascode amplifying circuit used for increasing a power supply rejection ratio, the negative feedback circuit provides the supply voltage VDD, processed through voltage stabilization, for the band-gap core circuit, and the starting circuit stretches the reference voltage source VREF when work begins so that the automatic biasing cascode amplifying circuit can work normally. According to the band-gap reference circuit, due to the facts that the supply voltage VDD processed through voltage stabilization is provided for the band-gap core circuit through the negative feedback circuit, and the automatic biasing cascode amplifying circuit is adopted inside for increasing the power supply rejection ratio, area and power consumption are saved.

Description

【Technical field】 [0001] The invention relates to a bandgap reference circuit, in particular to a bandgap reference circuit in a power management chip DC-DC converter. 【Background technique】 [0002] The bandgap reference circuit is an integral part of the DC-DC converter, due to the feedback voltage V of the PWM and PFM operating modes fb must be compared with a reference voltage generated by the bandgap reference circuit. Therefore, an accurate reference voltage can regulate the voltage accurately. [0003] The basic principle of a bandgap voltage reference is to use two voltages with opposite temperature coefficients to add with appropriate weights to produce a voltage with zero temperature coefficient. A bipolar transistor (BJT) has the following two characteristics: the base-emitter voltage Vbe of a bipolar transistor is inversely proportional to the absolute temperature; at different collector currents, the base-emitter voltage of two bipolar transistors The differe...

AI Technical Summary

Problems solved by technology

The bandgap reference proposed by some circuits in the prior art is a circuit that does not use an operational amplifier. Although this structure achieves high PSRR and low power consumption, the circuit requires a relatively large supply voltage (VDD>4.25V)

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