A New Power Management IC Architecture for Envelope Tracking Power Amplifier

A new supply modulator architecture for robust performance against the battery voltage variation is presented. The resulting modulator is an optimized power management integrated circuit (PMIC) for an envelope tracking (ET) power amplifier (PA). The basic topology of the PMIC is based on a hybrid switching amplifier combining a wideband class-AB buffered linear amplifier and a highly efficient switching-mode buck converter in a master-slave configuration. The additional boost converter regulates the supply voltage of the linear amplifier, while the supply of the buck converter is directly coupled to the battery. The proposed supply modulator achieves max/min efficiencies of 76.8/69.3% over the entire battery voltage range. The ET PA is operated at 4.5 V, providing higher output power, efficiency, and gain than at nominal 3.5-V design. The robust performance of the proposed PMIC is demonstrated.