Abstract: Methods and apparatuses are provided for achieving efficient power usage by a power amplifier. For example, there is provided an apparatus comprising: a processor unit providing one or more processor outputs, one of the processor outputs comprising a control voltage; and a variable gain amplifier operatively coupled to the processor and the power amplifier, wherein the variable gain amplifier comprises a piecewise linear circuit that receives the control voltage from the processor unit and provides a supply voltage to the power amplifier. In one embodiment, the processor unit is operatively coupled to a receiver that receives a feedback signal via radio link from a remote base station. The piecewise linear circuitry adjusts the supply voltage to the power amplifier at an exponential rate according to power requirements of the power amplifier.