Patent ID: 7598801

Claim:
A voltage regulator, comprising: an operational transconductance amplifier, having an inverting input terminal, a non-inverting input terminal, a first output terminal and a second output terminal, wherein there is an input offset voltage presented between the inverting input terminal and the non-inverting input terminal; an auto-zeroing unit, having a first input terminal, a third output terminal and a fourth output terminal, wherein the first input terminal is for receiving an input voltage, the third output terminal is coupled to the inverting input terminal, the fourth output terminal is coupled to the non-inverting input terminal, the auto-zeroing unit is for detecting the input offset voltage during a first period to thereby generate compensation voltage with the same polarity and the same voltage level as the input offset voltage and for using the compensation voltage to counterbalance the input offset voltage during a second period; a feedback unit, having a first feedback terminal and a second feedback terminal, wherein the first feedback terminal is coupled to the non-inverting input terminal and the feedback unit is for deciding a closed-loop gain of the operational transconductance amplifier; a first switching unit, having a second input terminal and a fifth output terminal, wherein the second input terminal is coupled to the first output terminal and the first switching unit is for making the fifth output terminal coupled to the second feedback terminal during the first period; and a second switching unit, having a third input terminal, a sixth output terminal and a seventh output terminal, wherein the third input terminal is coupled to the second output terminal, the second switching unit is for making the sixth output terminal coupled to the second feedback terminal during the second period and using the seventh output terminal to output an output voltage to a load circuit for use, the output voltage is the product of the input voltage and the closed-loop gain, and a load current of the load circuit has transient behaviour.