Bandgap Reference Circuit

Abstract

The present invention relates to a bandgap reference circuit, which includes a reference voltage source VREF, the reference voltage source VREF stretches the gate voltage V_REG to realize internal pre-regulation, and forms an internal pre-regulation circuit; a bandgap core circuit, the The bandgap core circuit is provided with a self-biased cascode amplifier circuit that improves the power supply rejection ratio; a negative feedback circuit, and the negative feedback circuit provides a stabilized power supply voltage VDD for the bandgap core circuit; A start-up circuit, the start-up circuit stretches the reference voltage source VREF at the beginning of operation to make the self-biased cascode amplifier circuit work normally. The bandgap reference circuit of the present invention provides a regulated power supply voltage for the bandgap core circuit through a negative feedback circuit, and at the same time internally adopts a self-biased cascode amplifier circuit to improve the power supply rejection ratio, saving area and power consumption.

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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