Power supply circuit for power amplifier and communication apparatus

1 . A power supply circuit configured to be coupled to a 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, 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 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.

2 . The power supply circuit according to claim 1 , wherein the envelope tracker comprises:

a switch circuit configured to output a low-frequency power component to the output-stage power amplifier; and

an envelope amplifier configured to output a high-frequency power component to the output-stage power amplifier.

3 . The power supply circuit according to claim 1 , wherein:

the power supply circuit further comprises an average power tracker; and

the power supply circuit is configured to select the average power tracker or the envelope tracker to supply power to the output-stage power amplifier.

4 . The power supply circuit according to claim 1 , wherein the charge pump is configured to provide a power supply voltage that is one-(N+1)th of an input voltage, and N is a positive integer.

5 . The power supply circuit according to claim 1 , wherein the charge pump is configured to provide a voltage that is N/(N+1)th of an input voltage, and N is a positive integer.

6 . A system comprising the power supply circuit and the power amplifier of claim 1 .

7 . 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.

8 . The communication apparatus according to claim 7 , wherein:

the power amplifier comprises a third capacitor, a resistor, an inductor, and a triode; and

a base of the triode is configured to receive the radio frequency signal using the third capacitor, the base of the triode is further configured to receive a bias voltage using the resistor, an emitter of the triode is coupled to a ground node, a collector of the triode is configured to receive a power supply voltage from the power supply circuit using the inductor, and the collector of the triode is further configured to output an amplified radio frequency signal.

9 . The communication apparatus according to claim 7 , further comprising a printed circuit board and an antenna, wherein

the communication apparatus is fixed on the printed circuit board, and the power amplifier is configured to transmit an amplified radio frequency signal through the antenna.

10 . The communication apparatus according to claim 7 , wherein the envelope tracker comprises:

a switch circuit configured to output a low-frequency power component to the output-stage power amplifier; and

an envelope amplifier configured to output a high-frequency power component to the output-stage power amplifier.

11 . The communication apparatus according to claim 7 , wherein the power supply circuit further comprises an average power tracker configured to select the average power tracker or the envelope tracker to supply power to the output-stage power amplifier.

12 . The communication apparatus according to claim 7 , wherein the charge pump is configured to provide a power supply voltage that is one-(N+1)th of an input voltage, and N is a positive integer.

13 . The communication apparatus according to claim 7 , wherein the charge pump is configured to provide a voltage output that is N/(N+1)th of an input voltage, and N is a positive integer.

14 . 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.

15 . The method of claim 14 , further comprising:

providing, by a switch circuit of the envelope tracker, a low-frequency power component to the output-stage power amplifier; and

providing, by an envelope amplifier, a high-frequency power component to the output-stage power amplifier.

16 . The method of claim 14 , further comprising:

tracking, by an average tracker, an average power of a radio frequency signal provided to the power amplifier; and

selecting one of an output of the average tracker or an output of the envelope tracker to supply power to the output-stage power amplifier.

17 . The method of claim 16 , wherein tracking the average power of the radio frequency signal comprises receiving a codeword corresponding to the average power of the radio frequency signal.

18 . The method of claim 14 , further comprising:

receiving a first radio frequency signal by the driving-stage power amplifier;

amplifying the received first radio frequency signal by the driving-stage power amplifier to provide a first amplified radio frequency signal; and

amplifying, by the output-stage power amplifier, the first amplified radio frequency signal to provide a second amplified radio frequency signal.

19 . The method of claim 14 , wherein supplying power to the driving-stage power amplifier comprises providing a power supply voltage that is one-(N+1)th of an input voltage, and N is a positive integer.

20 . The method of claim 14 , wherein supplying power to the driving-stage power amplifier comprises providing a voltage that is N/(N+1)th of an input voltage, and N is a positive integer.