One embodiment provides a system for generating a reference waveform. The system can include a first pulse-width modulation (PWM) channel configured to provide a first PWM waveform having a first duty cycle and a first frequency. A second PWM channel is configured to provide a second PWM waveform having a second duty cycle and the first frequency. Combinational logic is configured to combine the first PWM waveform and the second PWM waveform to generate a phase-shifted reference PWM waveform having the first frequency and a phase shift that is based on the first duty cycle and the second duty cycle.