Patent ID: 8664925

Claim:
A voltage regulator, comprising: an output transistor provided between a power supply terminal and an output terminal; an error amplifier for controlling a gate voltage of the output transistor so that a voltage of the output terminal becomes constant; a second transistor for connecting a substrate of the output transistor to the power supply terminal; a third transistor for connecting the substrate of the output transistor to the output terminal; and a comparator circuit for comparing a voltage of the power supply terminal with the voltage of the output terminal, and performing control of switching the second transistor and the third transistor based on a result of the comparing, wherein: the comparator circuit comprises: a fourth transistor including a source connected to the power supply terminal, a gate connected to a drain, and the drain connected to a first constant current circuit; and a fifth transistor including a source connected to the output terminal, a gate connected to the gate of the fourth transistor, and a drain connected to a second constant current circuit; and the comparator circuit outputs the result of the comparing based on a voltage of a connection point between the fifth transistor and the second constant current circuit; and a delay circuit for receiving the output of the comparator circuit to perform control of switching the second transistor and the third transistor, wherein the delay circuit performs the control to prevent the second transistor and the third transistor from being turned ON simultaneously.