Equalizer for envelope power supply circuitry

A wireless device comprising:

• transceiver circuitry;
• radio frequency power amplifier circuitry;
• and
• an envelope tracking integrated circuitry (ETIC) coupled between the transceiver circuitry and the radio frequency power amplifier circuitry, the ETIC comprising equalizer circuitry, signal processing circuitry coupled to the equalizer circuitry, and parallel amplifier circuitry coupled to the signal processing circuitry, the equalizer circuitry comprising a first operational amplifier and a second operational amplifier coupled in series;
• wherein:
• the first operational amplifier is configured to receive a target voltage signal and provide an intermediate signal based on the target voltage input signal;
• the second operational amplifier is configured to receive the intermediate signal and an inverted target voltage input signal and provide an equalized output signal;
• the signal processing circuitry is configured to process the equalized output signal to provide a processed equalized output signal;
• and
• the parallel amplifier circuitry is configured to amplify at least one battery voltage based on the processed equalized output signal to provide at least one envelope tracking power supply signal.

A method of operating a wireless device that comprises transceiver circuitry, radio frequency power amplifier circuitry, and an envelope tracking integrated circuitry (ETIC) coupled between the transceiver circuitry and the radio frequency power amplifier circuitry, the ETIC comprising equalizer circuitry, signal processing circuitry coupled to the equalizer circuitry, and parallel amplifier circuitry coupled to the signal processing circuitry, the equalizer circuitry comprising a first operational amplifier and a second operational amplifier coupled in series, with the first operational amplifier and the second operational amplifier being interconnected with one or more passive components such that a transfer function between an input of the first operational amplifier and an output of the second operational amplifier is a second-order complex-zero function, the method comprising:

• receiving, by the first operational amplifier, a target voltage input signal, and providing, by the first operational amplifier, an intermediate signal based on the target voltage input signal;
• receiving, by the second operational amplifier, the intermediate signal and an inverted target voltage input signal, and providing, by the second operational amplifier, an equalized output signal;
• processing the equalized output signal to provide a processed equalized output signal;
• amplifying at least one battery voltage based on the processed equalized output signal to provide at least one envelope tracking power supply signal;
• and
• supplying the at least one amplified battery voltage to the radio frequency power amplifier circuitry.