Low dropout linear regulator with quick transient response and high stability

Abstract

The invention discloses a low dropout linear regulator with quick transient response and high stability. The low dropout linear regulator comprises a power adjusting pipe, an error amplifier circuit and an ESR resistor. The error amplifier circuit comprises a main operational amplifier circuit and a buffering drive circuit. The low dropout linear regulator further comprises a transient response improving circuit and a compensation network circuit. The low dropout linear regulator has the advantages that a compensation network is provided to guarantee that when load currents change, phase margin doe not change, and stability of the low dropout linear regulator is guaranteed; an induction capacitor is additionally arranged on the compensation network, so that change of poles can be quickly tracked, moment stability can be maintained when load current jump occurs, and oscillation of output voltages is prevented; a transient response improving circuit structure is designed to improve load transient response, it is guaranteed that output of the transient response improving circuit has quick transient response capacity when the load currents of the output end jump, and grain and the phase margin can not change greatly.

Description

technical field [0001] The present invention relates to the technical field of power management, in particular to the design of a low-dropout linear regulator (LDO, low-Dropout Regulator). Background technique [0002] Power management technology is widely used in electronic consumer products, especially in portable electronic products such as notebook computers, smart phones, and PDAs. The application of power management is mainly to achieve the purpose of prolonging battery life and chip working time by improving the energy utilization rate of devices. [0003] A low-dropout linear regulator (LDO) is a linear regulated source whose output voltage is lower than the input voltage. Its basic function is to provide a stable and reliable constant power supply voltage. Its advantages are low voltage drop, low power consumption, small package size, low output ripple, and simple application scheme. The output ripple of the LDO is small, it filters out the noise in the circuit, a...

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Problems solved by technology

However, when the load current changes greatly, the secondary pole will change, and the ESR zero point cannot track the change of the pole very well, which will have a bad influence on the stability.

Moreover, if the output voltage overshoots or undershoots too much at the moment of the load current jump, it will directly affect the normal operation of the subsequent circuit modules.

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