Circuitry comprising a parallel amplifier circuit comprising a plurality of driver segments (2206D, 2206E) for controlling a power amplifier supply voltage (Vcc) to a radio frequency power amplifier and a switch mode power supply converter for providing modulated power to the power amplifier supply voltage (Vcc) and configured to cooperatively operate with the parallel amplifier circuit to form a power management system, which is configured to: • operate in a high power modulation mode when an expected output power generated by the radio frequency power amplifier is greater than or equal to a high power modulation mode threshold, operate in a medium power modulation mode when the expected output power generated by the radio frequency power amplifier is less than the high power modulation mode threshold but greater than or equal to a low power average power tracking, APT, modulation mode threshold, and operate in a low power APT modulation mode when the expected output power generated by the radio frequency power amplifier is less than the low power APT modulation mode threshold; • during the high power modulation mode, enable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide envelope tracking by setting a first segmentation configuration for the parallel amplifier circuit which enables all output driver segments (2206D, 2206E) of the parallel amplifier circuit; • during the medium power modulation mode, enable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide envelope tracking by setting a second segmentation configuration for the parallel amplifier circuit which disables at least one output driver segment of the parallel amplifier circuit; and • during the low power APT modulation mode, disable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide average power tracking; • wherein: • the radio frequency power amplifier is configured to sequentially transmit a plurality of communications slots; and • the selection of the high power modulation mode, the medium power modulation mode, and the low power APT modulation mode is based on the expected output power from the radio frequency power amplifier and is made on a communications slot to communications slot basis. • operate in a high power modulation mode when an expected output power generated by the radio frequency power amplifier is greater than or equal to a high power modulation mode threshold, operate in a medium power modulation mode when the expected output power generated by the radio frequency power amplifier is less than the high power modulation mode threshold but greater than or equal to a low power average power tracking, APT, modulation mode threshold, and operate in a low power APT modulation mode when the expected output power generated by the radio frequency power amplifier is less than the low power APT modulation mode threshold; • during the high power modulation mode, enable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide envelope tracking by setting a first segmentation configuration for the parallel amplifier circuit which enables all output driver segments (2206D, 2206E) of the parallel amplifier circuit; • during the medium power modulation mode, enable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide envelope tracking by setting a second segmentation configuration for the parallel amplifier circuit which disables at least one output driver segment of the parallel amplifier circuit; and • during the low power APT modulation mode, disable the switch mode power supply converter and control the power amplifier supply voltage (Vcc) to the radio frequency power amplifier to provide average power tracking; • wherein: • the radio frequency power amplifier is configured to sequentially transmit a plurality of communications slots; and • the selection of the high power modulation mode, the medium power modulation mode, and the low power APT modulation mode is based on the expected output power from the radio frequency power amplifier and is made on a communications slot to communications slot basis. • the radio frequency power amplifier is configured to sequentially transmit a plurality of communications slots; and • the selection of the high power modulation mode, the medium power modulation mode, and the low power APT modulation mode is based on the expected output power from the radio frequency power amplifier and is made on a communications slot to communications slot basis.