Envelope tracking amplifier apparatus

An envelope tracking (ET) amplifier apparatus comprising:

• a plurality of first amplifier circuits comprising a plurality of first input stages and a plurality of first output stages, respectively, the plurality of first amplifier circuits configured to amplify a radio frequency (RF) signal based on at least one first ET voltage;
• a plurality of second amplifier circuits comprising a plurality of second input stages and a plurality of second output stages, respectively, the plurality of second amplifier circuits configured to amplify the RF signal based on at least one second ET voltage;
• and
• an ET integrated circuit (IC) (ETIC) comprising:
• a tracker circuit configured to generate a low-frequency current at a common port;
• a plurality of amplifier ports coupled to the plurality of first amplifier circuits and the plurality of second amplifier circuits;
• and
• a plurality of voltage circuits coupled between the common port and the plurality of amplifier ports, respectively, the plurality of voltage circuits configured to generate the at least one first ET voltage and the at least one second ET voltage based on a plurality of ET target voltages, respectively;
• wherein a selected voltage circuit among the plurality of voltage circuits is configured to:
• generate a reference ET voltage based on a maximum ET target voltage among the plurality of ET target voltages;
• and
• provide the reference ET voltage to the common port and a selected amplifier port coupled to the selected voltage circuit among the plurality of amplifier ports.