High-accuracy low drop-out voltage regulator

Abstract

The invention provides a high-accuracy low drop-out voltage regulator which comprises an output circuit, a feedback circuit and an error amplifying circuit. The output circuit comprises a power transistor and a mirror image transistor. A source level and a grid electrode of the power transistor are respectively connected with a source level and a grid electrode of the mirror image transistor. A drain electrode of the power transistor is the output end of the output circuit. The error amplifying circuit controls current on the mirror image transistor according to feedback voltage provided by the feedback circuit and reference voltage. The low drop-out voltage regulator further comprises an auxiliary regulator circuit which is connected between the drain electrode of the power transistor and a drain electrode of the mirror image transistor. The auxiliary regulator circuit regulates drain electrode voltage of the mirror image transistor to be equal with drain electrode end voltage of the power transistor. A mirror image relation between the power transistor and the mirror image transistor is guaranteed and alignment accuracy of output voltage is ensured.

Description

【Technical field】 [0001] The invention relates to the field of power management, in particular to a low dropout voltage regulator. 【Background technique】 [0002] Low dropout voltage regulators are widely used in various electronic systems, especially digital systems that require low power supply and fast load response. The low dropout voltage regulator of the output voltage of the current mirror can not only respond quickly to the load change, but also the quiescent current it consumes will decrease synchronously with the decrease of the load current, which reduces power consumption and improves efficiency. [0003] figure 1 It is a circuit diagram of a low dropout voltage regulator 100 in the prior art. The low dropout voltage regulator includes a current mirror output circuit 110, a feedback circuit 120, an error amplifier circuit 130, and the output terminals VOUT and Capacitor CL between ground VSS and load resistor RL. The current mirror output circuit 110 includes ...

AI Technical Summary

Problems solved by technology

The change of the power supply voltage VDD will directly affect the adjustment accuracy of the output voltage VOUT, especially when the power supply voltage VDD decreases and the power transistor M8 works in the sub-threshold region or linear region, the transistors M7 and M8 can no longer maintain the proportional mirror image of the current mirror At the same time, the gain and power supply rejection ratio PSRR of the system feedback loop will be seriously reduced

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