In accordance with an embodiment, a power supply circuit configured to be coupled to a power amplifier that includes a driving-stage power amplifier and an output-stage power amplifier. The power amplifier is configured to amplify a power of a radio frequency signal, the driving-stage power amplifier is configured to receive the radio frequency signal, and the output-stage power amplifier is configured to receive a radio frequency signal amplified by the driving-stage power amplifier. The power supply circuit includes: a charge pump configured to supply power to the driving-stage power amplifier; and an envelope tracker configured to supply power to the output-stage power amplifier, wherein the charge pump and the envelope tracker are configured to supply power to the power amplifier.