Power efficiency is an important design requirement of power amplifiers. To improve power efficiency, a solution proposed in this present disclosure includes an all-digital zero-voltage switching apparatus for directly driving a switching power amplifier through a desired current pulse shape. The apparatus includes a digital engine and a digital-to-analog converter (DAC). The digital engine processes baseband data and generates a digital output. The digital output of the digital engine drives the DAC to generate a digitally controlled current output having that desired current pulse shape. The digitally controlled current output is used to directly drive the switch power amplifier (704) to improve power efficiency. The digitally controlled current output comprising digitally generated current pulses is controlled accurately by the digital engine and the DAC, and thus allows the switching power amplifier (204) to operate optimally with higher power efficiency than conventional power amplifiers.