Low dropout linear regulator and overshoot suppression method thereof

Abstract

The invention provides an LDO (Low Dropout Regulator) and an overshoot suppression method thereof. The LDO comprises a power transistor, an error amplifier, a first transistor and a sampling comparison unit. The first end and the second end of the power transistor serve as the input end and the output end of the LDO respectively. The error amplifier amplifies an error between a feedback signal representing an output voltage signal of the LDO and a reference voltage signal, and sends an error amplification result to the control end of the power transistor. The sampling comparison unit is used for sampling dynamic current in the error amplifier, comparing a dynamic current sampling value with reference current and then outputting a current adjusting signal, and when the dynamic current sampling value is larger than the reference current, the current adjusting signal is used for conducting the first transistor so as to reduce the on-resistance of the power transistor. According to the scheme, the overshoot voltage can be suppressed in the LDO starting process or the load changing process. The circuit structure is simple, static power consumption is not increased, and the overshoot suppression effect is good.

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