Patent ID: 11971734
Assignee: SG MICRO CORP
Field: Control (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A control circuit of a low dropout linear regulator, which comprises a power transistor connected between a power supply terminal and an output terminal, wherein the control circuit is configured to drive the power transistor to convert a power supply voltage at the power supply terminal into an output voltage, wherein the control circuit comprises:
an error amplifier, configured to drive the power transistor according to a voltage difference between a feedback voltage of the output voltage and a reference voltage;
a foldback current-limiting protection circuit, connected with a control terminal of the power transistor for performing foldback control on an output current of the power transistor and short circuit protection;
an undershoot suppression circuit, connected with the control terminal of the power transistor for pulling a voltage at the control terminal of the power transistor to low voltage level when the output voltage undershoots; and
an output detection circuit, configured to judge whether the output voltage rises to a preset voltage value in a startup stage, and disable the undershoot suppression circuit and foldback control performed by the foldback current-limiting protection circuit before the output voltage rises to the preset voltage value.