Circuits capable of trickle precharge and/or trickle discharge

• US 20050212484A1
• Filed: 04/27/2004
• Published: 09/29/2005
• Est. Priority Date: 03/25/2004
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Li, Guoxing, Liu, Liusheng, Denning, Bruce S.
• Granted Patent: US 7,180,268 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation

Abstract

Battery charging circuitry and systems are provided. One embodiment may include at least one switch having a full conduction state and a controllable conduction state and switch control circuitry capable of sensing a condition. The switch control circuitry may further be capable of generating at least one control signal capable of controlling the conduction state of the switch based on, at least in part, the sensed condition.

Claims

1. An apparatus comprising:

at least one switch having a full conduction state and a controllable conduction state; and

switch control circuitry capable of sensing a condition, said switch control circuitry further capable of generating at least one control signal capable of controlling said conduction state of said switch based on, at least in part, said sensed condition.

2. The apparatus of claim 1, wherein said switch comprises a charge switch to control charge current to a battery, said condition comprising a trickle charge condition for said battery, and wherein said charge switch is responsive to said control signal representative of said presence of said trickle charge condition to enter said controllable conduction state thereby allowing a trickle charge current to flow from a power source to said battery.

3. The apparatus of claim 2, wherein said charge switch is responsive to said control signal representative of an absence of said trickle charge condition to enter said full conduction state thereby allowing a full charge current to flow from said power source to said battery, said full charge current being greater than said trickle charge current.

4. The apparatus of claim 1, wherein said switch comprises a discharge switch to control discharge current provided from an associated battery, said condition comprises a fault condition, and said discharge switch is responsive to said control signal representative of said presence of said fault condition to enter said controllable conduction state thereby allowing a trickle discharge current to flow from said battery.

5. The apparatus of claim 4, wherein said discharge switch is responsive to said control signal representative of an absence of said fault condition to enter said full conduction state thereby allowing a full discharge current to flow from said battery, said full discharge current being greater than said trickle discharge current.

6. The apparatus of claim 4, wherein said a presence of said fault condition is sensed if a discharging current level provided by said battery is greater than a fault current threshold.

7. The apparatus of claim 1, wherein said switch control circuitry comprises an analog to digital converter (ADC) to receive analog signal representative of current level of a battery and provide a digital signal representative of said current level of said battery, a controller configured to receive said digital signal and provide a digital output control signal to a digital to analog converter (DAC), said DAC providing said control signal to said switch.

8. A system, comprising:

A battery pack comprising at least one rechargeable battery cell;

at least one switch having a full conduction state and a controllable conduction state; and

switch control circuitry capable of sensing a condition, said switch control circuitry further capable of generating at least one control signal capable of controlling said conduction state of said switch based on, at least in part, said sensed condition.

9. The system of claim 8, wherein said switch comprises a charge switch to control charge current to said at least one battery cell, said condition comprising a trickle charge condition for said battery, and wherein said charge switch is responsive to said control signal representative of said presence of said trickle charge condition to enter said controllable conduction state thereby allowing a trickle charge current to flow from a power source to said at least one battery cell.

10. The system of claim 9, wherein said charge switch is responsive to said control signal representative of an absence of said trickle charge condition to enter said full conduction state thereby allowing a full charge current to flow from said power source to said at least one battery cell, said full charge current being greater than said trickle charge current.

11. The system of claim 8, wherein said switch comprises a discharge switch to control discharge current provided from said at least one battery cell, said condition comprises a fault condition, and said discharge switch is responsive to said control signal representative of said presence of said fault condition to enter said controllable conduction state thereby allowing a trickle discharge current to flow from said at least one battery cell.

12. The system of claim 11, wherein said discharge switch is responsive to said control signal representative of an absence of said fault condition to enter said full conduction state thereby allowing a full discharge current to flow from said at least one battery cell, said full discharge current being greater than said trickle discharge current.

13. The system of claim 11, wherein said a presence of said fault condition is sensed if a discharging current level provided by said battery is greater than a fault current threshold.

14. The system of claim 8, wherein said switch control circuitry comprises an analog to digital converter (ADC) to receive analog signal representative of current level of said at least one battery cell and provide a digital signal representative of said current level of said least one battery cell, a controller configured to receive said digital signal and provide a digital output control signal to a digital to analog converter (DAC), said DAC providing said control signal to said switch.

15. A method, comprising:

sensing at least one of a trickle charge or a trickle discharge condition for a battery; and

controlling the conduction state of at least switch to permit said battery to at least one of receive a trickle charge current or generate a trickle discharge current.

16. The method of claim 15, further comprising:

controlling the conduction state of a discharge switch into a saturation conduction range to permit said battery to generate a controllable trickle discharge current.

17. The method of claim 15, further comprising:

controlling the conduction state of a charge switch into a saturation conduction range to permit said battery to receive a controllable trickle charge current.