Charging current adapter circuit for cells or batteries

• US 6,002,239 A
• Filed: 11/04/1997
• Issued: 12/14/1999
• Est. Priority Date: 10/23/1997
• Status: Expired due to Fees

• Current Assignee: Saft Finance Sarl (Totalenergies Se)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Maloizel, Serge
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US08/964,456
• Time in Patent Office: 770 Days
• Field of Search: 320/116, 320/126, 320/128, 320/132, 320/135, 320/136, 320/FOR 104, 320/FOR 126, 320/FOR 128
• US Class Current: 320/136
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

A cell charging voltage adapter circuit, and a battery including such a circuit, wherein the charging circuit includes terminals (2, 3) of resistor (8) between one of the connecting terminals (2; 3) and one of the output terminals (6; 7) and a comparator 910) between the connecting terminals and adapted to control the variable resistor in accordance with the results of comparing the voltage between the connecting terminals and a nominal voltage.

Claims

1. A circuit comprising:

a cell voltage adapter for charging a cell, said charging adapter including

connecting terminals of a cell connected to output terminals,

a variable resistor between one of the connecting terminals and one of the output terminals; and

a comparator connected between the connecting terminals for controlling the variable resistor in accordance with the results of comparing the voltage between the connecting terminals and a nominal voltage.

2. A circuit according to claim 1, wherein the comparator is adapted to control the variable resistor so that the voltage between the connecting terminals is equal to the nominal voltage.

3. A circuit according to claim 1, further comprising:

a diode in parallel with the variable resistor and adapted to conduct in the direction from the connecting terminal to the output terminal.

4. A circuit according to claim 1, characterized in that the variable resistor is a transistor.

5. A circuit according to claim 4, wherein said transistor is a MOSFET.

6. A circuit according to claim 1, wherein the comparator includes an operational amplifier for comparing the voltage between the connecting terminals and the voltage supplied by a voltage source.

7. A circuit according to claim 1, wherein the comparator includes a voltage divider connected between the connecting terminals, a voltage source and an operational amplifier for comparing the voltage supplied by the voltage divider and the voltage supplied by the voltage source.

8. A battery comprising:

at least one cell and a charging voltage adapter circuit, the circuit including

connecting terminals connected to the terminals of at least one cell, and connected to output terminals,

a variable resistor connected between one of the connecting terminals and one of the output terminals, and

a comparator connected between the connecting terminals for controlling the variable resistor in accordance with the results of comparing the voltage between the connecting terminals and a nominal voltage.

9. A battery according to claim 8, wherein the nominal voltage is the nominal charging voltage of the cell.

10. A battery according to claim 8, wherein the adapter circuit is an integrated circuit mounted on a casing of the battery.

11. A battery according to claim 8, the comparator controls the variable resistor so that the voltage between the terminals of the at least one cell is equal to the nominal voltage.

12. A battery according to claim 8, wherein the circuit further includes a diode in parallel with the variable resistor that conduct in the direction from the connecting terminal to the output terminal.

13. A battery according to claim 8, wherein the variable resistance is a transistor.

14. A circuit according to claim 13, wherein said transistor is a MOSFET.

15. A battery according to claim 8, wherein the comparator an operational amplifier comparing the voltage between the terminals of at least one cell and the voltage supplied by a voltage source.

16. A battery according to claim 8, wherein the comparator includes a voltage divider connected between the connecting terminals, a voltage source and an operational amplifier comparing the voltage supplied by the voltage divider and the voltage supplied by the voltage source.