Multi-stage power converter

A power converter for providing an output voltage with an output-to-input conversion ratio, the power converter having a ground port, a first port, and a second port, wherein when the power converter operates as a step-down converter the first port receives an input voltage and the second port provides the output voltage and when the power converter operates as a step-up converter the second port receives an input voltage and the first port provides the output voltage;

• the power converter comprising
• a first conversion circuit coupled to the first port;
• a second conversion circuit coupled to the second port;
• and
• a driver;
• wherein the first conversion circuit comprises a first flying capacitor coupled to a first network of switches, and a first inductor and a second inductor both coupled to the second conversion circuit;
• wherein the second conversion circuit comprises a reservoir capacitor and a second flying capacitor coupled to a second network of switches;
• the driver being adapted to drive the first and the second network of switches with a sequence of states during a drive period, the sequence of states comprising at least one of a first phase, and a second phase,
• wherein when the power converter operates as a step-down converter, the first phase is configured to charge the second flying capacitor and the second phase is configured to discharge the second flying capacitor by coupling the second flying capacitor in parallel to the reservoir capacitor, and when the power converter operates as a step-up converter, the first phase is configured to discharge the second flying capacitor by coupling the second flying capacitor in parallel to the reservoir capacitor and the second phase is configured to charge the second flying capacitor.