SUPERCAPACITOR BACKUP POWER SUPPLY WITH BI-DIRECTIONAL POWER FLOW

• US 20110215644A1
• Filed: 03/25/2011
• Published: 09/08/2011
• Est. Priority Date: 11/13/2006
• Status: Active Grant

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Psion Teklogix (Motorola Solutions, Inc.)
• Inventors: FORSYTHE, Larry, BAKER, Keith
• Granted Patent: US 8,593,113 B2
• Time in Patent Office: Days
• US Class Current: 307/64
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02J 9/061 for DC powered loads

Abstract

A system for providing backup power supply to a device is provided. The system includes a supercapacitor and a single circuit for charging and discharging of a supercapacitor. The single circuit operates with an inductor to provide for charging and discharging of the supercapacitor.

Claims

1-33. -33. (canceled)

34. A system for backup power supply, the system comprising:

a supercapacitor for backing up a potential node;

an inductor coupled to the supercapacitor and the potential node, the inductor operating in a bi-directional mode to charge and discharge the supercapacitor;

a first switch and second switch coupled to the inductor, the supercapacitor and the potential node, the first switch being used to modulate flow of current from a power source to the supercapacitor through the inductor when the power source is available at the potential node, and the second switch being used to modulate flow of current from the supercapacitor to the potential node through the inductor when the power source is lost at the potential node.

35. The system according to claim 34, further comprising a first diode coupled to the first switch.

36. The system according to claim 35, wherein the first diode is coupled in parallel to the first switch such that the first diode is reverse biased when the power source is available at the potential node and forward biased when the power source is lost at the potential node.

37. The system according to claim 35, wherein the first diode is coupled in parallel to the first switch such that the first diode is forward biased when the power source is available at the potential node and reverse biased when the power source is lost at the potential node.

38. The system according to claim 35, wherein the first diode is an intrinsic diode of the Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).

39. The system according to claim 35, wherein the first diode is a schottky diode.

40. The system according to claim 34, further comprising a second diode coupled to the second switch.

41. The system according to claim 40, wherein the second diode is coupled in parallel to the second switch such that the second diode is reverse biased when the power source is available at the potential node and forward biased when the power source is lost at the potential node.

42. The system according to claim 40, wherein the second diode is an intrinsic diode of the MOSFET.

43. The system according to claim 40, wherein the second diode is a schottky diode.

44. The system according to claim 34, wherein at least one of the first switch and the second switch is a MOSFET.

45. The system according to claim 34, further comprising a controller for operating the first switch and the second switch.

46. The system according to claim 45, wherein the controller comprises a charging mode for charging the supercapacitor using the first switch, and a backup mode for discharging the supercapacitor using the second switch.

47. The system according to claim 45, wherein the controller comprises a current monitor for monitoring the inductor current.

48. The system according to claim 45, wherein the controller comprises a voltage monitor for monitoring the voltage level at the potential node.

49. The system according to claim 45, wherein the controller operates the first switch and the second switch to form a buck converter with a synchronous rectifier.

50. The system according to claim 45, wherein the controller operates the first switch and the second switch to form a boost converter with a synchronous rectifier.