Patent attributes
An envelope tracking (ET) power amplifier circuit is disclosed. The ET power amplifier circuit includes ET tracker circuitry configured to output an ET modulated output voltage having an output voltage envelope that tracks a target voltage envelope of an ET modulated target voltage. Impedance adjustment circuitry in the ET power amplifier circuit is provided between a first node and a second node coupled to a feedback voltage input and a voltage output of the ET tracker circuitry, respectively. A power amplifier circuit(s) includes a first amplifier and a second amplifier coupled respectively to the first node and the second node. As such, it is possible to configure the impedance adjustment circuitry to provide adjustment impedance to offset output impedance of the ET tracker circuitry, thus helping to reduce voltage error in the ET power amplifier circuit.
