Systems for charging a battery in a closed loop configuration

• US 8,125,189 B2
• Filed: 04/11/2008
• Issued: 02/28/2012
• Est. Priority Date: 04/18/2005
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Formenti, Jose Antonio Vieira
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): PACHECO, ALEXIS BOATENG
• Application Number:
  US12/101,682
• Publication Number:
  US 20080253053A1
• Time in Patent Office: 1,418 Days
• Field of Search: 320/106, 320/134, 320/135, 320/136, 320/132, 320/183, 320/163, 320/140, 320/31, 320/112, 320/114, 361/90, 361/103, 361/58, 361/93.8, 361/93.9
• US Class Current: 320/134
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A system is provided for charging a battery with an AC adapter. The system includes a first closed loop electrical path between the battery and the AC adapter. The first closed loop electrical path includes a first monitoring circuit for monitoring at least one first parameter of the system and a control circuit for dynamically adjusting the AC adapter output to the battery in response to the at least one first parameter exceeding an associated predetermined threshold. The system includes a second closed loop electrical path between the battery and the AC adapter. The second closed loop electrical path includes a second monitoring circuit for monitoring at least one second parameter of the system and a protection circuit responsive to the at least one second parameter exceeding an associated predetermined threshold for protecting the system until the AC adapter reaches a predetermined value.

Claims

1. A system that controls an AC adapter output of an AC adapter for charging a battery and providing power to a system power bus, the system comprising:

a first closed control loop that includes a first monitoring circuit that monitors at least one first parameter associated with charging of the battery and/or powering the system power bus and a control circuit that transmits a control signal to the AC adapter to cause adjustment to the AC adapter output in response to the at least one parameter exceeding an associated first predetermined threshold; and

a second closed control loop that includes a second monitoring circuit that monitors transients associated with at least one second parameter associated with charging of the battery and/or powering the system power bus and controls a resistance of a protection circuit between the AC adapter output and the battery and/or system power bus to regulate the second parameter in response to the at least second parameter exceeding an associated second predetermined threshold to protect the battery and/or system power bus, until the first closed control loop adjusts the AC adapter output to a predetermined value.

2. The system according to claim 1, wherein the at least one first parameter and the at least second parameter both comprise at least one of charging current of the battery, the battery voltage, the AC adapter output current, the AC adapter output voltage, the voltage at the system power bus and a difference between the AC adapter output and the voltage at the system power bus.

3. The system according to claim 1, wherein the second predetermined threshold is set to be higher than the first predetermined threshold if the first and second parameters are of the same type.

4. The system according to claim 3, wherein predetermined value is the second predetermined threshold.

5. The system according to claim 1, wherein the second monitoring circuit includes an operational amplifier that outputs an error signal that increases the resistance of the protection circuit when the charging current of the battery exceeds an associated second predetermined threshold and wherein the first closed control loop includes an operational amplifier that outputs an error signal to the controller that transmits a control signal to the AC adapter to adjust the AC adapter output to the predetermined value when the charging current of the battery exceeds an associated first predetermined threshold.

6. The system according to claim 1, wherein the second monitoring circuit includes a first operational amplifier that outputs an error signal that increases the resistance of the protection circuit when the voltage at the system power bus exceeds an associated second predetermined threshold and a second operational amplifier that outputs an error signal that increases the resistance of the protection circuit when the charging current of the battery exceeds an associated second predetermined threshold.

7. The system according to claim 6, wherein the protection circuit is a power MOSFET and outputs of the first and second operation amplifiers are both coupled to a gate of the power MOSFET and the resistance of the power MOSFET is based on the value of one of the error signals.

8. The system according to claim 6, wherein the second monitoring circuit includes a third operational amplifier that outputs an error signal that turns off the protection circuit when the difference between the AC adapter output and the voltage at the system power bus voltage exceeds an associated second predetermined threshold.

9. The system according to claim 1, wherein the first monitoring circuit comprises;

a first operational amplifier that outputs a first error signal based on a difference between a charging current of the battery and an associated first predetermined threshold;

a second operational amplifier that outputs a second error signal based on a difference between a battery voltage and an associated first predetermined threshold;

a third operational amplifier that outputs a third error signal based on a difference between a voltage at the system power bus and an associated first predetermined threshold; and

a summer that provides a total error signal to the control circuit based on a sum of the first, second and third error signals.

10. A portable electronic device comprising the system according to claim 1.

11. A portable electronic device having a battery, the portable electronic device adapted to have the battery charged by an AC adapter output of and AC adapter, the portable electronic device comprising:

a system power bus coupled to the AC adapter output and the battery through a resistive element;

a first closed control loop that includes a first monitoring circuit that monitors at least one first parameter associated with charging of the battery and/or powering the system power bus and provides an error signal to a control circuit that transmits a control signal to the AC adapter to cause adjustment to the AC adapter output in response to the at least one parameter exceeding an associated first predetermined threshold; and

a second closed control loop that includes a second monitoring circuit that monitors transients associated with at least one second parameter associated with charging of the battery and/or powering the system power bus and generates an error signal that controls a resistance of the resistive device between the AC adapter output and the battery and/or system power bus to regulate the second parameter in response to the at least one second parameter exceeding an associated second predetermined threshold to protect the battery and/or system power bus, until the first closed control loop adjusts the AC adapter output to a predetermined value.

12. The portable electronic device according to claim 11, wherein the second predetermined threshold is set to be higher than the first predetermined threshold if the first and second parameters are of the same type and wherein the predetermined value is the second predetermined threshold.

13. The portable electronic device according to claim 11, wherein the second monitoring circuit includes an operational amplifier that outputs an error signal that increases the resistance of the protection circuit when the charging current of the battery exceeds an associated second predetermined threshold and wherein the first closed control loop includes an operational amplifier that outputs an error signal to the controller that transmits a control signal to the AC adapter to adjust the AC adapter output to the predetermined value when the charging current of the battery exceeds an associated first predetermined threshold.

14. The portable electronic device according to claim 11, wherein the second monitoring circuit comprises:

a first operational amplifier that outputs an error signal that increases the resistance of the resistive element when the voltage at the system power bus exceeds an associated second predetermined threshold;

a second operational amplifier that outputs an error signal that increases the resistance of the resistive element when the charging current of the battery exceeds an associated second predetermined threshold; and

a third operational amplifier that outputs an error signal that turns off the resistive when the difference between the AC adapter output and the voltage at the system power bus voltage exceeds an associated second predetermined threshold.

15. The portable electronic device according to claim 11, wherein the first monitoring circuit comprises;

a first operational amplifier that outputs a first error signal based on a difference between a charging current of the battery and an associated first predetermined threshold;

a second operational amplifier that outputs a second error signal based on a difference between a battery voltage and an associated first predetermined threshold;

a third operational amplifier that outputs a third error signal based on a difference between a voltage at the system power bus and an associated first predetermined threshold; and

a summer that provides a total error signal to the control circuit based on a sum of the first, second and third error signals.

16. The portable electronic device according to claim 11, further comprising memory for storing data and a processor for processing data both powered over the system power bus.

17. A system for charging a battery with an AC adapter, the system including a system power bus operatively connected to the AC adapter, the system comprising:

a first monitoring means for monitoring a parameter associated with charging of the battery and/or powering of the system power bus;

a control means for dynamically adjusting AC adapter output when the parameter monitored by the first monitoring means exceeds an associated first predetermined threshold;

a second monitoring means for monitoring transients of the parameter associated with charging of the battery and/or powering of the system power bus; and

protection means responsive to the second monitoring means when the parameter monitored by the second monitoring means exceeds a second predetermined threshold, wherein the protection means activates to protect the battery and/or system power bus, by controlling a resistance between the AC adapter and the battery to regulate the parameter monitored by the second monitoring means until the first monitoring means and the control means adjust the AC adapter output to the second predetermined threshold.

18. The system according to claim 17, wherein the activation of the protection means comprises increasing resistance of a resistive element connected between the AC adapter and system power bus and battery.

19. The system according to claim 17, wherein the parameter is battery charge current.

20. The system according to claim 17, wherein the parameter is a difference between the adapter voltage and voltage at the system power bus.