US Patent 9991851 Multi-mode radio frequency (RF) power amplifier circuit

A multi-mode radio frequency (RF) power amplifier circuit is disclosed. The multi-mode RF power amplifier circuit can operate in a low-resource block (RB) mode and a high-RB mode. The multi-mode RF power amplifier circuit includes a driver stage power amplifier and an output stage power amplifier to amplify an RF input signal and generate an RF output signal. A control circuit is configured to provide a constant envelope voltage and an envelope tracking (ET) supply voltage to the driver stage power amplifier and the output stage power amplifier, respectively, in the high-RB mode. As a result, it is possible to optimize RF performance and reduce sensitivity of the driver stage power amplifier and the output stage power amplifier in the high-RB mode, without increasing costs and footprint of the multi-mode RF power amplifier circuit.