Patent ID: 7915866

Claim:
A system for backup power supply, the system comprising: a supercapacitor for backing up a potential node; and a single circuit coupled to the supercapacitor and the potential node, for charging and discharging the supercapacitor, the single circuit including: an inductor and a first switch, coupled in series between the supercapacitor and the potential node, the inductor operating in a bi-directional mode to charge and discharge the supercapacitor; a first diode coupled in parallel to the first switch; a second switch having a first node coupled to the supercapacitor and a second node coupled to a node coupling the inductor and the first switch; and a second diode coupled in parallel to the second switch, wherein, when power source is available at the potential node, the single circuit charges the supercapacitor to a desired level by operating the first switch to modulate the power source node such that current flows from the potential to the supercapacitor through the inductor, and when the power source is lost at the potential node, the single circuit modulates the discharge of the supercapacitor by operating the second switch such that current flows from the supercapacitor to the potential node through the inductor, thereby providing backup power to the potential node.