Hybrid DC-DC Power Converter with Small Voltage Conversion Ratio

8) A method for operating a power converter, wherein the power converter comprises

• an inductor coupled to the input port of the power converter;
• a first stage comprising an input node;
• a first switch coupled to the input node of the first stage and to an output port of the power converter;
• a second switch coupled to the output port of the power converter;
• a third switch coupled to the second switch of the first stage and to a reference potential;
• and a flying capacitor coupled to the input node and to an intermediate node between the second switch and the third switch of the first stage;
• and
• a second stage comprising an input node;
• a first switch coupled to the input node of the second stage and to the output port of the power converter;
• a second switch coupled to the input node of the first stage;
• a third switch coupled to the second switch of the second stage and to the reference potential;
• and a flying capacitor coupled to the inductor and to an intermediate node between the second switch and the third switch of the second stage;
• wherein the method comprises
• operating the first and second stage alternatingly in a first and a second phase;
• wherein in the first phase, the first switches and the third switches of the first and second stage are closed, and the second switches of the first and second stage are open;
• and wherein in the second phase, the first switches and the third switches of the first and second stage are open, and the second switches of the first and second stage are closed;
• determining a target voltage conversion ratio between the output voltage and the input voltage;
• and
• deactivating or activating the first stage in dependence of the target voltage conversion ratio;
• and
• wherein deactivating a particular stage comprises
• maintaining permanently closed the first switch and the third switch of the particular stage;
• and
• maintaining permanently open the second switch of the particular stage.