Multi-level power converter with light load flying capacitor voltage regulation

A method of operating a multi-level power converter comprising a first switching element, a second switching element, a third switching element, a fourth switching element, an inductor, and a flying capacitor, wherein a first terminal of said inductor is connected to a switching terminal connecting the second switching element and the third switching element, wherein a first terminal of said flying capacitor is connected to a terminal connecting the first switching element and the second switching element, and wherein a second terminal of said flying capacitor is connected to a terminal connecting the third switching element and the fourth switching element, the method comprising the steps of:

• generating, by a first feedback circuit, control signals for setting the switching elements in a plurality of switching states for regulating an output voltage or an output current of the multi-level power converter;
• generating, by a second feedback circuit, based on a capacitor voltage across the flying capacitor, temporary control signals for setting the switching elements in a temporary switching state in which the flying capacitor is charged or discharged using an inductor current flowing through the inductor;
• generating, by the first feedback circuit, a first control signal and a second control signal both included within said control signals, the first control signal and the second control signal configured for correspondingly turning off the first and the second switching elements almost simultaneously,
• selecting, by the second feedback circuit, one of the first control signal and the second control signal based on the capacitor voltage, and generate a respective first temporary control signal or second temporary control signal both included within said temporary control signals, by delaying, by the second feedback circuit, the selected one of the first control signal and the second control signal by a delay interval such that the flying capacitor is charged or discharged by the inductor current during said delay interval.

A multi-level power converter comprising:

• a first switching element, a second switching element, a third switching element, and a fourth switching element;
• an inductor, wherein a first terminal of said inductor is connected to a switching terminal connecting the second switching element and the third switching element;
• a flying capacitor, wherein a first terminal of said flying capacitor is connected to a terminal connecting the first switching element and the second switching element, and wherein a second terminal of said flying capacitor is connected to a terminal connecting the third switching element and the fourth switching element;
• a first feedback circuit configured to generate control signals for setting the switching elements in a plurality of switching states for regulating an output voltage or an output current of the multi-level power converter;
• and
• a second feedback circuit configured to generate, based on a capacitor voltage across the flying capacitor, temporary control signals for setting the switching elements in a temporary switching state in which the flying capacitor is charged or discharged using an inductor current flowing through the inductor;
• wherein
• the first feedback circuit is configured to generate a third control signal and a fourth control signal both included within said control signals, the third control signal and the fourth control signal are configured for correspondingly turning off the third and the fourth switching element almost simultaneously, and
• the second feedback circuit is configured to select one of the third control signal and the fourth control signal based on the capacitor voltage, and generate a respective third temporary control signal or fourth temporary control signal both included within said temporary control signals, by delaying the selected one of the third control signal and the fourth control signal by a delay interval such that the flying capacitor is charged or discharged by the inductor current during said delay interval.

A method of operating a multi-level power converter comprising a first switching element, a second switching element, a third switching element, a fourth switching element, an inductor, and a flying capacitor, wherein a first terminal of said inductor is connected to a switching terminal connecting the second switching element and the third switching element, wherein a first terminal of said flying capacitor is connected to a terminal connecting the first switching element and the second switching element, and wherein a second terminal of said flying capacitor is connected to a terminal connecting the third switching element and the fourth switching element, the method comprising the steps of:

• generating, by a first feedback circuit, control signals for setting the switching elements in a plurality of switching states for regulating an output voltage or an output current of the multi-level power converter;
• generating, by a second feedback circuit, based on a capacitor voltage across the flying capacitor, temporary control signals for setting the switching elements in a temporary switching state in which the flying capacitor is charged or discharged using an inductor current flowing through the inductor;
• generating, by the first feedback circuit, a third control signal and a fourth control signal both included within said control signals, the third control signal and the fourth control signal are configured for correspondingly turning off the third and the fourth switching element almost simultaneously,
• selecting, by the second feedback circuit, one of the third control signal and the fourth control signal based on the capacitor voltage, and generate a respective third temporary control signal or fourth temporary control signal both included within said temporary control signals, by delaying, by the second feedback circuit, the selected one of the third control signal and the fourth control signal by a delay interval such that the flying capacitor is charged or discharged by the inductor current during said delay interval.

A multi-level power converter comprising:

• a first switching element, a second switching element, a third switching element, and a fourth switching element;
• an inductor, wherein a first terminal of said inductor is connected to a switching terminal connecting the second switching element and the third switching element;
• a flying capacitor, wherein a first terminal of said flying capacitor is connected to a terminal connecting the first switching element and the second switching element, and wherein a second terminal of said flying capacitor is connected to a terminal connecting the third switching element and the fourth switching element;
• a first feedback circuit configured to generate control signals for setting the switching elements in a plurality of switching states for regulating an output voltage or an output current of the multi-level power converter;
• and
• a second feedback circuit configured to generate, based on a capacitor voltage across the flying capacitor, temporary control signals for setting the switching elements in a temporary switching state in which the flying capacitor is charged or discharged using an inductor current flowing through the inductor;
• wherein the second feedback circuit comprises
• a delay circuit, wherein the delay circuit is configured to generate the temporary control signals by delaying the control signals generated by the first feedback circuit;
• a comparator configured to compare the capacitor voltage against a target capacitor voltage;
• and
• at least one multiplexer configured to forward, based on a comparison result generated by the comparator, either a control signal within the control signals generated by the first feedback circuit or a temporary control signal within the temporary control signals generated by the second feedback circuit for controlling the switching behavior of one of the switching elements.

A method of operating a multi-level power converter comprising a first switching element, a second switching element, a third switching element, a fourth switching element, an inductor, and a flying capacitor, wherein a first terminal of said inductor is connected to a switching terminal connecting the second switching element and the third switching element, wherein a first terminal of said flying capacitor is connected to a terminal connecting the first switching element and the second switching element, and wherein a second terminal of said flying capacitor is connected to a terminal connecting the third switching element and the fourth switching element, the method comprising the steps of:

• generating, by a first feedback circuit, control signals for setting the switching elements in a plurality of switching states for regulating an output voltage or an output current of the multi-level power converter;
• generating, by a second feedback circuit, based on a capacitor voltage across the flying capacitor, temporary control signals for setting the switching elements in a temporary switching state in which the flying capacitor is charged or discharged using an inductor current flowing through the inductor;
• generating, by a delay circuit of the second feedback circuit, the temporary control signals by delaying the control signals generated by the first feedback circuit;
• comparing, by a comparator of the second feedback circuit, the capacitor voltage against a target capacitor voltage;
• and
• forwarding, by at least one multiplexer of the second feedback circuit, based on a comparison result generated by the comparator, either a control signal within the control signals generated by the first feedback circuit or a temporary control signal within the temporary control signals generated by the second feedback circuit for controlling the switching behavior of one of the switching elements.