Power supply circuit for power amplifier and communication apparatus

A communication apparatus, comprising:

• a digital baseband processor;
• a transmitter coupled to the digital baseband processor;
• a power amplifier coupled to the transmitter, the power amplifier comprising a driving-stage power amplifier and an output-stage power amplifier, wherein the power amplifier is configured to amplify a power of a radio frequency signal provided by the transmitter, 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;
• and
• a power supply circuit coupled to the power amplifier, the power supply circuit comprising:
• 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, wherein:
• the charge pump comprises a first switch, a second switch, a third switch, a fourth switch, a first capacitor, and a load capacitor,
• a first end of the second switch, a first end of the load capacitor, and a second end of the third switch are all coupled to an output end of the charge pump,
• a second end of the second switch is coupled to a first end of the first capacitor and a first end of the first switch,
• a second end of the first switch is coupled to an input end of the charge pump;
• a first end of the fourth switch and a second end of the load capacitor are coupled to each other and coupled to a ground node, and
• a second end of the fourth switch is coupled to a second end of the first capacitor and a first end of the third switch.

A method of operating a power amplifier comprising a driving-stage power amplifier, and an output-stage power amplifier having an input coupled to an output of the driving-stage power amplifier, the method comprising:

• supplying power, by a charge pump, to the driving-stage power amplifier;
• and
• supplying power, by an envelope tracker, to the output-stage power amplifier, wherein:
• the charge pump comprises a first switch, a second switch, a third switch, a fourth switch, a first capacitor, and a load capacitor,
• a first end of the second switch, a first end of the load capacitor, and a second end of the third switch are all coupled to an output end of the charge pump,
• a second end of the second switch is coupled to a first end of the first capacitor and a first end of the first switch,
• a second end of the first switch is coupled to an input end of the charge pump;
• a first end of the fourth switch and a second end of the load capacitor are coupled to each other and coupled to a ground node, and
• a second end of the fourth switch is coupled to a second end of the first capacitor and a first end of the third switch.