Short activation time voltage regulator

摘要

Provided is a voltage regulator having a simple circuit configuration in which a protection circuit is not erroneously operated, and delay time of activation of the protection circuit is short. The voltage regulator includes: a protection circuit configured to control an output transistor when an abnormality of the voltage regulator is detected; a first constant current circuit configured to supply operating current to the protection circuit; and a detection circuit configured to detect output current flowing through the output transistor, to thereby control the first constant current circuit. The detection circuit is further configured to detect the output current with a predetermined reference current value. The protection circuit is further configured to control the output transistor so that the output current does not fall below the reference current value.

主权项

1. A voltage regulator configured to control an output transistor through error amplification between a reference voltage and a feedback voltage, to thereby output a predetermined output voltage,
the voltage regulator comprising: a protection circuit configured to control the output transistor when an abnormality of the voltage regulator is detected, wherein the protection circuit comprises:
a detection unit configured to detect the abnormality of the voltage regulator; anda first transistor and a second transistor connected in series between a gate of the output transistor and a source of the output transistor, andwherein when the second transistor is turned on based on an output of the detection unit, a gate-source voltage of the output transistor remains by a drain-source voltage of the first transistor; a first constant current circuit configured to supply operating current to the protection circuit; and a detection circuit configured to detect output current flowing through the output transistor, to thereby control the first constant current circuit, the detection circuit being further configured to detect the output current with a predetermined reference current value, the protection circuit being further configured to control the output transistor so that the output current does not fall below the predetermined reference current value.