A multi-phase power supply circuit includes at least a first phase and a second phase (such as semi-resonant DC-DC power converter circuits), each of which output current to power a load. The first phase includes a first inductor device through which first current is delivered to the load. The second phase includes a second inductor device through which second current is delivered to the load. A current monitor circuit of the multi-phase power supply circuit is operable to monitor current through the second inductor device. Control circuitry of the multi-phase power supply circuit is operable to adjust timing of activating a control switch in the second phase to an ON state based on the monitored current. Timing of the phases is adjusted to achieve a common switching and zero current switching amongst the phases.