Circuit configuration for protecting a battery against deep discharge

• US 20030076073A1
• Filed: 11/19/2002
• Published: 04/24/2003
• Est. Priority Date: 05/19/2000
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Waltenberger, Helmut
• Granted Patent: US 7,006,340 B2
• Time in Patent Office: Days
• US Class Current: 320/135
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

The inventive circuit configuration has only two poles and is connected in series between the battery and the load. The circuit configuration interrupts the electric circuit for a short time in order to gauge the condition of the battery. The interruption is so short that it is not perceived by a user.

Claims

1. A circuit configuration for protecting a battery against deep discharge, comprising:

two external terminals for connecting to a series connected battery and load;

a controllable switch connected between said two external terminals;

a series circuit including an energy storage device and a charging device for said energy storage device, said series circuit connected between said two external terminals; and

a control circuit connected to said switch;

said energy storage device being for supplying said control circuit;

said control circuit for generating a control signal in a manner dependent on a limit value and a voltage across said switch being determined when said switch is open;

said control signal causing said switch to be open when said voltage across said switch lies below said limit value; and

said control signal causing said switch to be open during regularly occurring, short time intervals and otherwise closed when said voltage across said switch lies above said limit value.

2. The circuit configuration according to claim 1, wherein:

said control circuit includes a voltage monitoring circuit for generating said control signal, and a pulse generator circuit for generating regularly occurring, momentary pulses;

said voltage monitoring circuit and said pulse generator circuit are designed and coupled to said switch such that said switch is open when said voltage across said switch is below said limit value; and

said voltage monitoring circuit and said pulse generator circuit are designed and coupled to said switch such that said switch is open during regularly occurring, short time intervals and otherwise closed when said voltage across said switch is above said limit value.

3. The circuit configuration according to claim 2, in combination with the battery, wherein:

said energy storage device is an auxiliary accumulator;

said charging device is a switching device;

said switching device connects said auxiliary accumulator to the battery for charging purposes, but otherwise isolates the battery and said auxiliary accumulator.

4. The circuit configuration according to claim 2, wherein:

said energy storage device is a capacitor;

said charging device is a diode; and

said diode is connected such that said diode is conductive if said voltage across said switch is greater than a voltage across said capacitor, and said diode is otherwise turned off.

5. The circuit configuration according to claim 1, in combination with the battery, wherein:

said energy storage device is an auxiliary accumulator;

said charging device is a switching device;

said switching device connects said auxiliary accumulator to the battery for charging purposes, but otherwise isolates the battery and said auxiliary accumulator.

6. The circuit configuration according to claim 1, wherein:

said energy storage device is a capacitor;

said charging device is a diode; and

said diode is connected such that said diode is conductive if said voltage across said switch is greater than a voltage across said capacitor, and said diode is otherwise turned off.

7. The circuit configuration according to claim 6, comprising a diode interposed between said switch and said control circuit;

said diode used when determining said voltage across said switch.

8. The circuit configuration according to claim 5, wherein:

said control circuit includes a voltage divider, a first transistor, a second transistor, and a resistor;

said voltage divider is connected in parallel with said capacitor, said voltage divider has a tap, said capacitor has a first terminal and a second terminal, said switch has a control terminal;

said first transistor has a controlled path connected between said control terminal of said switch and said first terminal of said capacitor, said first transistor has a control terminal;

said second transistor has a controlled path connected between said control terminal of said first transistor and said second terminal of said capacitor, said second transistor has a control terminal connected to said tap of said voltage divider; and

said resistor is connected between said tap of said voltage divider and said control terminal of said switch.

9. The circuit configuration according to claim 1, wherein said switch is a transistor.

10. The circuit configuration according to claim 1, in combination with a base having an incandescent lamp serving as the load;

said circuit configuration being integrated into said base.

11. The circuit configuration according to claim 1, in combination with a planar housing having a base area corresponding to a base area of the battery;

said circuit configuration being integrated into said housing.

12. The circuit configuration according to claim 1, wherein said limit value can be set externally.

13. The circuit configuration according to claim 1, wherein said limit value is set fixedly.

14. The circuit configuration according to claim 1, comprising:

an apparatus for setting said limit value in a self-learning manner.