Linear voltage regulator with improved responses to source transients

摘要

A linear voltage regulator has a regulating transistor with a first channel electrode receiving an input voltage source and a second electrode providing an output voltage. A control electrode of the regulating transistor is controlled by an error amplifying circuit based on comparison between a feedback signal of the output voltage and a reference voltage. An event detecting circuit is coupled to the input voltage source for detecting occurrence of a transient in the input voltage source. In response to the detected transient event, an enable controlling circuit generates an enable signal for determining an effective operation time of a voltage clamping circuit. During such effective operation time, a potential difference between the first channel electrode and the control electrode is limited within a predetermined clamp voltage for preventing the regulating transistor from being dramatically changed in operation.