An integrated Low Dropout (LDO) linear voltage regulator provides improved current
limiting. A differential voltage amplifier compares an output voltage to reference
voltage and controls a pass transistor to make the output voltage substantially
match the reference voltage. This is accomplished by sensing the output voltage
of the voltage regulator for application to a first input of the differential amplifier
and coupling a second input of the differential amplifier to the reference voltage.
A current sense transistor utilizes current mirroring techniques to sense the current
passing through the pass transistor to the output. This sensed current is compared
to a reference current. The result of that comparison is fed back to the differential
voltage amplifier to in a manner that increases the apparently sensed output voltage
in situations where the sensed current exceeds the reference current.