Multi mode bias modulator operating in envelope tracking mode or average power tracking mode and envelope tracking power amplifier using the same

An envelope tracking power amplifier, comprising:

• a multi-mode bias modulator configured to generate a variable bias voltage using a linear amplifier and switching amplifiers operating in envelope tracking mode or average power tracking mode in accordance with an operation mode control signal that determines any one of the envelope tracking mode and the average power tracking mode;
• and
• a power amplifier configured to be biased in response to the variable bias voltage, and to power amplify a radio frequency (RF) signal and output the amplified RF signal to an antenna;
• wherein the multi-mode bias modulator comprises:
• the linear amplifier configured to drive a linear amplification bias current in accordance with an AC component of an envelope signal in the envelope tracking mode, and to be inactivated in the average power tracking mode;
• a first switching amplifier configured to drive a first switching amplification bias current in accordance with a first duty ratio determined based on a magnitude of a DC component of the envelope signal in the envelope tracking mode, and to be inactivated in the average power tracking mode;
• and
• a second switching amplifier configured to be inactivated in the envelope tracking mode, and to drive a second switching amplification bias current in accordance with a second duty ratio corresponding to an error between the variable bias voltage and a predetermined reference voltage in the average power tracking mode;
• wherein the multi-mode bias modulator is operated to, during operation in the envelope tracking mode, generate a variable bias current by combining the linear amplification bias current output by the linear amplifier with the first switching amplification bias current output by the first switching amplifier and, during operation in the average power tracking mode, generate the variable bias current as the second switching amplification bias current that is current driven by the second switching amplifier;
• and
• wherein the variable bias voltage is related to an output resistance of the multi-mode bias modulator, an input resistance of the power amplifier, and the variable bias current.

An envelope tracking power amplifier, comprising:

• a multi-mode bias modulator configured to generate a variable bias voltage using a linear amplifier and a switching amplifier operating in envelope tracking mode or average power tracking mode in accordance with an operation mode control signal that determines any one of the envelope tracking mode and the average power tracking mode;
• and
• a power amplifier configured to be biased in response to the variable bias voltage, and to power amplify a radio frequency (RF) signal and output the amplified RF signal to an antenna;
• wherein the multi-mode bias modulator comprises:
• the linear amplifier configured to drive a linear amplification bias current in accordance with an AC component of an envelope signal in the tracking mode, and to be inactivated in the average power tracking mode;
• and
• the switching amplifier configured to drive a first switching amplification bias current corresponding to a DC component of the envelope signal in the envelope tracking mode, and to drive a second switching amplification bias current in accordance with a duty ratio corresponding to a magnitude of an error between the variable bias voltage and a predetermined reference voltage in the average power tracking mode;
• wherein the multi-mode bias modulator is operated to, during operation in the envelope tracking mode, generate a variable bias current by combining the linear amplification bias current driven by the linear amplifier with the first switching amplification bias current driven by the switching amplifier and, during operation in the average power tracking mode, generate the variable bias current as the second switching amplification bias current that is driven by the switching amplifier;
• and
• wherein the variable bias voltage is related to an output resistance of the multi-mode bias modulator, an input resistance of the power amplifier, and the variable bias current.

An envelope tracking power amplifier, comprising:

• a multi-mode bias modulator configured to generate a variable bias voltage using a linear amplifier and a switching amplifier operating in envelope tracking mode or average power tracking mode in accordance with an operation mode control signal that determines any one of the envelope tracking mode and the average power tracking mode;
• and
• a power amplifier configured to be biased in response to the variable bias voltage, and to power amplify a radio frequency (RF) signal and output the amplified RF signal to an antenna;
• wherein the multi-mode bias modulator comprises:
• the linear amplifier configured to drive a linear amplification bias current in accordance with an AC component of an envelope signal in the envelope tracking mode, and to be inactivated in the average power tracking mode;
• and
• the switching amplifier configured to drive a first switching amplification bias current corresponding to a DC component of the envelope signal in the envelope tracking mode, and to generate a second switching amplification bias current in accordance with a duty ratio corresponding to a magnitude of an error between the variable bias voltage and a predetermined reference voltage in the average power tracking mode;
• wherein the multi-mode bias modulator is operated to, during operation in the envelope tracking mode, generate a variable bias current by combining the linear amplification bias current output by the linear amplifier with the first switching amplification bias current output by the switching amplifier and, during operation in the average power tracking mode, generate the variable bias current as a second switching amplification bias current that is driven by the switching amplifier;
• and
• wherein the variable bias voltage is related to an output resistance of the multi-mode bias modulator, an input resistance of the power amplifier, and the variable bias current.