Patent ID: 7508177

Claim:
A regulator circuit for receiving an input voltage, the regulator circuit comprising: a linear regulator, including a first feedback loop, for generating a first regulator voltage from the input voltage with the first feedback loop; a switching regulator, including a second feedback loop connected to the first feedback loop, for generating a second regulator voltage from the input voltage with the second feedback loop; and a loop control circuit, connected to the first feedback loop, for controlling the first feedback loop to lower the first regulator voltage generated by the linear regulator when the switching regulator is activated; wherein the linear regulator includes: an error amplifier for receiving a reference voltage and a feedback voltage of the first regulator voltage via the first feedback loop and for generating an amplification voltage in accordance with the difference between the reference voltage and the feedback voltage; and a transistor for generating the first regulator voltage from the input voltage in response to the amplification voltage; and the loop control circuit controls the first feedback loop to raise the feedback voltage fed back to the error amplifier.