Power control circuitry that is configurable as either a Low Dropout (LDO)
voltage regulator or a switching DC--DC converter for controlling a
variable supply voltage provided to a power amplifier of a mobile
terminal is provided. The power control circuitry includes an output
stage including first and second output transistors, an analog control
system, and a digital control system. When in LDO voltage regulator mode,
the analog control system provides an analog control signal to the first
transistor based on an adjustable power control signal and a feedback
signal indicative of the variable supply voltage, and the digital control
system operates to disable the second output transistor. When in DC--DC
converter mode, an output stage of the analog control system is disabled,
and the digital control system provides binary control signals to the
first and second transistors based on the adjustable power control signal
and the feedback signal.