US Patent 11038464 Envelope tracking amplifier apparatus

An envelope tracking (ET) amplifier apparatus is provided. The ET amplifier apparatus includes an ET integrated circuit (IC) (ETIC) and a distributed ETIC (DETIC) coupled to the ETIC. The DETIC may be configured to provide a distributed voltage to a distributed amplifier circuit for amplifying a distributed radio frequency (RF) signal. In examples discussed herein, the ETIC is configured to generate a low-frequency current, which can affect the distributed voltage, at a desired level based on a feedback signal received from the DETIC. The DETIC may be configured to generate the feedback signal based on an indication(s) related to the distributed voltage. By dynamically adjusting the low-frequency current, and thus the distributed voltage, based on the feedback signal, it may be possible to maintain operating efficiency of the distributed amplifier circuit across a wider range of modulation bandwidth with minimal cost and/or size impact on the ET amplifier apparatus.