Patent ID: 8710822

Claim:
A DC-DC converter circuit comprising: a first coupling terminal of a first end of an inductive component and a second coupling terminal of a second end of the inductive component; a DC supply terminal to receive a DC input supply voltage; first, second, third, fourth and fifth switches including respective control terminals to select states of the first, second, third, fourth and fifth switches; a first output terminal connected to a first capacitor and serving as a positive DC voltage node relative to a ground terminal; a second output terminal connected to a second capacitor and serving as a negative DC voltage node relative to the ground terminal; and a digital controller coupled to the respective control terminals of the first, second, third, fourth and fifth switches so as to control the respective states thereof; wherein the first switch is arranged between the second capacitor and the first coupling terminal of the inductive component, the second switch is arranged between the first capacitor and the second coupling terminal of the inductive component, the third switch is coupled between the DC supply terminal and the first coupling terminal of the inductive component, the fourth switch is coupled between the first coupling terminal of the inductive component and ground, and the fifth switch is coupled between the second coupling terminal of the inductive component and ground; wherein the inductive component is coupled between the first and second capacitors for supplying charging current to at least one of the first and second capacitors in at least a first, a second, and a third converter state under control of the digital controller; wherein in the first converter state, the second and third switches are set to respective closed states to supply charging current to the first capacitor through the inductive component; in the second converter state, the first and fifth switches are set to respective closed states to supply charging current to the second capacitor through the inductive component; in the third converter state, the first switch and the second switch are set to respective closed states to supply charging current from the first capacitor to the second capacitor through the first and second coupling terminals of the inductive component; and the first and second switches are unidirectional current conduction devices.