A power converter circuit. In one aspect, the power converter circuit includes a first buck converter coupled in series to a second buck converter at a junction, and a control circuit coupled to each of the first and second buck converters. In another aspect, the control circuit is arranged to sense a voltage at the junction, compare the sensed voltage to a first threshold voltage and in response to the sensed voltage being at a voltage lower than the first threshold voltage, the control circuit operates the first buck converter and disables the second buck converter. In yet another aspect, the control circuit is arranged to compare the sensed voltage to a second threshold voltage and in response to the sensed voltage being at a voltage higher than the second threshold voltage, the control circuit operates the second buck converter and disables the first buck converter.