Circuit and method for RF power amplifier power regulation and modulation envelope tracking

A circuit comprising:

• a power amplifier operable to receive an input signal and generate an amplified output signal;
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a linear amplifier operable to perform modulation envelope control for the power amplifier;
• wherein:
• the switching converter is coupled in series with the linear amplifier;
• the circuit is operable to operate in one of multiple modes;
• the switching converter is operable to output the regulated voltage for the power amplifier in one of the modes;
• the linear amplifier is operable to receive the regulated voltage and output a tracked voltage for the power amplifier in another of the modes;
• and
• the linear amplifier is operable to output the tracked voltage by tuning the regulated voltage to track a reference input voltage and outputting the tracked voltage to the power amplifier.

A circuit comprising:

• a power amplifier operable to receive an input signal and generate an amplified output signal;
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a linear amplifier operable to perform modulation envelope control for the power amplifier;
• wherein:
• the switching converter is coupled in series with the linear amplifier;
• the circuit is operable to operate in one of multiple modes;
• the linear amplifier is operable to receive the regulated voltage and output a tracked voltage for the power amplifier in each of the modes;
• and
• the switching converter comprises:
• a difference amplifier operable to receive a reference input voltage and a second input voltage;
• and
• a selector operable to provide the second input voltage to the difference amplifier, the second input voltage comprising one of:
• (i) a voltage generated within the switching converter and (ii) a voltage generated within the linear amplifier, depending on the mode of the circuit.

A circuit comprising:

• a power amplifier operable to receive an input signal and generate an amplified output signal;
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a linear amplifier operable to perform modulation envelope control for the power amplifier;
• wherein:
• the switching converter is operable to provide the regulated voltage directly to the power amplifier;
• and
• the linear amplifier is operable to adjust a bias of the power amplifier to provide envelope tracking for the power amplifier.

A circuit comprising:

• a power amplifier operable to receive an input signal and generate an amplified output signal;
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a first linear amplifier operable to perform modulation envelope control for the power amplifier;
• and
• a second linear amplifier coupled in parallel with at least the switching converter.

A circuit comprising:

• a power amplifier operable to receive an input signal and generate an amplified output signal;
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a linear amplifier operable to perform modulation envelope control for the power amplifier;
• wherein:
• the switching converter is operable to receive an enable signal enabling the generation of the regulated voltage;
• and
• the switching converter is operable to enter a steady state before the linear amplifier is enabled.

A wireless device comprising:

• a power amplifier;
• transmit processing circuitry operable to generate a signal to be amplified by the power amplifier;
• an antenna operable to transmit the signal generated by the transmit processing circuitry and amplified by the power amplifier;
• and
• power and modulation control circuitry comprising:
• a switching converter operable to generate a regulated voltage and to perform power control for the power amplifier;
• and
• a linear amplifier operable to perform modulation envelope control for the power amplifier;
• wherein:
• the linear amplifier is operable to receive a ramp reference input voltage;
• and
• the switching converter is operable to receive a peak reference input voltage associated with a voltage that is at least as large as a peak value of the ramp reference input voltage.

A method comprising:

• receiving an input signal and generating an amplified output signal using a power amplifier;
• generating a regulated voltage and performing power control for the power amplifier using a switching converter;
• and
• performing modulation envelope control for the power amplifier using a linear amplifier, the linear amplifier receiving a ramp reference input voltage;
• wherein the switching converter receives a peak reference input voltage associated with a voltage that is at least as large as a peak value of the ramp reference input voltage.