Multi-level power converter with flyback capacitor pre-charge

A multi-level power converter, comprising:

• an output terminal;
• a reference terminal;
• an inductor;
• a flying capacitor;
• a first switching stage comprising:
• a first switch connected to the output terminal and connected to the flying capacitor at a first node;
• a second switch connected to the flying capacitor at a second node and connected to the reference terminal;
• a second switching stage comprising:
• a third switch connected to the first node and the inductor;
• and
• a fourth switch connected to the inductor and the second node;
• a charging circuit connected to the flying capacitor and the output terminal;
• a sensing amplifier connected to the first node and the second node to sense a flying capacitor voltage of the flying capacitor;
• a comparator configured to generate a disable signal to disable the charging circuit responsive to the flying capacitor voltage being at least a predetermined fraction of a voltage at the output terminal;
• and
• a linear regulator connected to the output terminal and configured to power the sensing amplifier and the comparator during a start-up cycle of the multi-level power converter.

A method for controlling a multi-level power converter, comprising:

• connecting a first switching stage to an output terminal and a flying capacitor;
• connecting a second switching stage to an inductor and the first switching stage;
• generating a supply voltage from a voltage at the output terminal;
• controlling a charging circuit to pre-charge the flying capacitor using the supply voltage during a start-up cycle of the multi-level power converter;
• providing a second flying capacitor associated with one of an additional level of the multi-level power converter or an additional stage of the multi-level power converter;
• and
• controlling a second charging circuit to pre-charge the second flying capacitor using the supply voltage during the start-up cycle of the multi-level power converter.