Patent ID: 7157892

Claim:
A voltage regulator for generating a regulated output voltage in response to an externally supplied enable control signal, the voltage regulator comprising: a bandgap reference generator for generating a bandgap voltage having a predetermined voltage level; a soft-start control circuit for generating a ramped voltage that gradually increases during a startup period and gradually decreases during a shutdown period, the startup period occurring after the enable control signal is asserted, and the shutdown period occurring after the enable control signal is de-asserted; a reference voltage comparator having a first input terminal connected to the soft-start control circuit and a second input terminal connected to the bandgap reference generator, wherein the reference voltage comparator includes including means for generating a reference signal that is equal to the ramped voltage while the ramped voltage is lower than the predetermined voltage level of the bandgap signal, and is equal to the bandgap signal when the predetermined voltage level is lower than the ramped voltage; an output circuit for generating the regulated output voltage in response to the reference signal; and a bandgap control circuit for controlling the bandgap reference generator to maintain the bandgap voltage at the predetermined voltage level during the shutdown period until the regulated output voltage decreases below a predetermined low reference voltage.