Voltage sensor for detecting cell voltages

Patent 5652501 Issued on July 29, 1997. Estimated Expiration Date:

December 12, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3531706

3543043

3576487

3593100

3890556

3900785

Latch circuit
Patent #: 3988643
Issued on: 10/26/1976
Inventor: Morris

Charging system
Patent #: 4021717
Issued on: 05/03/1977
Inventor: Furuishi, et al.

Multi-cell battery protection system
Patent #: 4061955
Issued on: 12/06/1977
Inventor: Thomas , et al.

Electronic DC battery charger
Patent #: 4061956
Issued on: 12/06/1977
Inventor: Brown , et al.

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Inventors

Assignee

Unitrode Corporation

Application

No. 353620 filed on 12/12/1994

US Classes:

340/636.15, By voltage320/118, With discharge of cells or batteries320/134, With battery or cell condition monitoring (e.g., for protection from overcharging, heating, etc.)324/433, To compare battery voltage with a reference voltage324/434, To determine plural cell condition340/636.2Including charging circuit

Examiners

Primary: Wong, Peter S.
Assistant: Shin, K.

Attorney, Agent or Firm

Weingarten, Schurgin, Gagnebin & Hayes

Foreign Patent References

0319020 EP 06/13/1989
2547420 FR. 01/13/1968
2438149 DE 02/13/1976
3611484 DE 10/13/1987
3716069 DE 12/13/1987
0748589 SU 07/13/1980

International Classes

H02J 007/00
G01N 027/416

Abstract

A battery charger/monitor circuit for charging and/or monitoring a plurality of series-connected cells, including a voltage sensor for sensing the voltage across each of the cells to provide a high cell voltage signal proportional to the highest voltage across any of the cells and a low cell voltage signal proportional to the lowest voltage across any of the cells. The circuit is operable in a monitor mode or a charge mode. In the monitor mode, the cells are disconnected from a load if the low cell voltage signal decreases to a first predetermined level. The circuit includes a controller which provides a control signal in response to the high cell voltage signal, the low cell voltage signal and a current sense signal, for controlling the charging of the cells. In the charge mode, the cells receive a constant charge current until the high cell voltage signal reaches a second predetermined level, after which the voltage across the cell charged to the highest voltage is held substantially constant, causing the charge current to be reduced.

Other References

Soviet Inventions Illustrated data sheet, Derwent Publications Ltd., Rochdale House, England, Feb. 3, 1982, pp. 12-13
Soviet Inventions Illustrated data sheet, Derwent Publications Ltd., Rochdale House, England, Aug. 8, 1984, p. 4
K.V. Kordesch, Journal of Electrochemical Science and Technology, Technical Notes, Charging Method for Batteries Using the Resistance-free Voltage as Endpoint Indication, vol. 119, Aug. 1972, pp. 1053-105