A power amplifier receives an input signal and generates an amplified output signal. A switching converter generates a regulated voltage and performs power control for the power amplifier. A linear amplifier performs modulation envelope control for the power amplifier. The switching converter may be coupled in series with the linear amplifier, and this circuit may operate in one of multiple modes. For example, the linear amplifier may output a tracked voltage to the power amplifier in GSM/polar EDGE mode, and the switching converter may output the regulated voltage to the power amplifier in WCDMA/UMTS mode. The linear amplifier could also output the tracked voltage in both modes, and a selector could select the appropriate feedback voltage for the switcher. The switching converter could also provide the regulated voltage directly to the power amplifier, and the linear converter could adjust a bias of the power amplifier to provide envelope tracking.

 
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