Power supply for a pulsed load

• US 20050077880A1
• Filed: 10/21/2004
• Published: 04/14/2005
• Est. Priority Date: 05/15/2001
• Status: Active Grant

• Current Assignee: Cap-Xx Ltd.
• Original Assignee: Cap-Xx Ltd.
• Inventors: Keshishian, Sarkis, Turner, Geoffrey Alan, Mahon, Peter John, Paul, George Lange
• Granted Patent: US 6,998,822 B2
• Time in Patent Office: Days
• US Class Current: 320/166
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A power supply (1) for a pulsed load (2) includes a first energy storage device in the form of a battery (3) which is in parallel with a second energy storage device in the form of a supercapacitor (4) Battery (3) and supercapacitor (4) are respectively modelled as: an ideal battery (7) in series with an internal resistance (8); and an ideal capacitor (9) in series with an equivalent series resistance (ESR) (10). Through use of a supercapacitor (4) having a low ESR with respect to the resistance (8), the power supply (1) facilitates continuity of supply to load (2). That is, during peak demand more of the load current will be supplied by supercapacitor (4) due to the lower ESR. Moreover, during times of lower load current demands the battery recharges the supercapacitor. This reduces the peak current needed to be provided by the battery and thereby improves battery longevity.

Claims

1-25. -25. (canceled)

26. A power supply for supplying a portable electronic device with a pulsed load profile, the power supply including an energy storage device, the energy storage device including:

a battery having a predetermined internal resistance R;

two terminals for allowing electrical connection to the battery; and

a supercapacitor connected in parallel with the terminals and having a predetermined equivalent series resistance ESR, wherein ESR<

0.25 R and a capacitance provided by the supercapacitor is sufficient to limit the battery current to a predetermined maximum, the power supply having supply rails for engaging the terminals of the energy storage device.

27. A power supply according to claim 26, wherein the terminals are moved out of engagement with the supply rails to allow the like terminals of a like energy storage device to be moved into engagement with the supply rails.

28. A power supply including:

a battery for providing a battery current and having two terminals for electrically connecting with a load that demands a pulsed current; and

a supercapacitor connected in parallel with the terminals for maintaining the ratio of the RMS value of the battery current and the average value of the battery current at less than about 1.5.

29. A power supply according to claim 28, wherein the supercapacitor maintains the ratio of the RMS value of the battery current and the average value of the battery current at less than about 1.3.

30. A power supply according to claim 28, wherein the supercapacitor maintains the ratio of the RMS value of the battery current and the average value of the battery current at less than 1.1.

31. An energy storage device including:

a battery for providing a battery current and having two terminals for electrically connecting with a load that demands a pulsed current; and

a supercapacitor connected in parallel with the terminals for maintaining the ratio of the RMS value of the battery current and the average value of the battery current at less than about 1.5.

32. An energy storage device according to claim 31, wherein the supercapacitor maintains the ratio of the RMS value of the battery current and the average value of the battery current at less than about 1.3.

33. An energy storage device according to claim 31, wherein the supercapacitor maintains the ratio of the RMS value of the battery current and the average value of the battery current at less than 1.1.