Switching battery charging systems and methods

• US 20070188134A1
• Filed: 02/16/2006
• Published: 08/16/2007
• Est. Priority Date: 02/16/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Summit Microelectronics, Incorporated (Qualcomm, Inc.)
• Inventors: Hussain, M., Adkins, Kenneth, Paparrizos, Georgios
• Granted Patent: US 7,834,591 B2
• Time in Patent Office: Days
• US Class Current: 320/114
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 2207/30 Charge provided using DC bus or data bus of a computer
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Embodiments of the present invention include techniques for charging a battery using a switching regulator. Some embodiments include programmable switching battery chargers that can be configured using digital techniques. Other embodiments include switching battery chargers that modify the battery current based on sensed circuit conditions such as battery voltage or input current to the switching regulator. In one embodiment, the present invention includes a USB battery charger.

Claims

1. A Universal Serial Bus (USB) battery charger comprising:

a switching regulator having at least one switching transistor, the switching transistor having first input and a first output, wherein the first input of the switching transistor is coupled to a USB power source;

a filter having a first input and a first output, wherein the first input of the filter is coupled to the first output of the switching transistor; and

a battery coupled to the first output of the filter,

wherein the switching regulator is configured to receive a USB voltage, and in accordance therewith, generate a switching signal to the control terminal of the switching transistor, and wherein a switching current and switching voltage at the output of the switching transistor are coupled through the filter to generate a filtered current and a filtered voltage to charge the battery.

2. The battery charger of claim 1 wherein the filtered voltage is sensed by a voltage controller to control the switching signal at the control terminal of the switching transistor.

3. The battery charger of claim 2 wherein the voltage controller includes a first input coupled to a programmable data storage element, a second input coupled to at least one voltage sense input, and an output coupled to the control input of the switching transistor, wherein the programmable data storage element configures the voltage controller to generate a programmed voltage to said battery if the voltage on said battery is above the first threshold.

4. The battery charger of claim 1 wherein the filtered current is sensed by a current controller to control the switching signal at the control terminal of the switching transistor.

5. The battery charger of claim 4 wherein the current controller includes a first input coupled to a programmable data storage element, a feedback input coupled to at least one current sense input, and an output coupled to the control input of the switching transistor, and wherein the programmable data storage element configures the current controller to supply a first programmed current to said battery if a voltage on said battery is below a first threshold.

6. The battery charger of claim 4 further comprising receiving an input signal indicating a maximum input current, and programming the current controller to set a maximum battery current based on the maximum input current.

7. The battery charger of claim 4 wherein the current controller has a control input for setting the filtered current, and wherein the control input of the current controller is coupled to the first input of the switching transistor or the battery to reduce the filtered current as the voltage on the battery increases.

8. The battery charger of claim 1 wherein the filtered current is greater than a first input current into the first input of the switching transistor, and the filtered current is reduced as the voltage on the battery increases.

9. The battery charger of claim 1 wherein the USB voltage is in a range of at least 4.1 volts to 5.25 volts.

10. A method of charging a battery from a Universal Serial Bus (USB) port comprising:

receiving a first input voltage and a first input current at the input of a switching regulator from a USB power source;

coupling an output of the switching regulator to a terminal of a battery;

generating a first output voltage and a first output current at the terminal of the battery;

sensing the first output current into the battery or a first output voltage on the battery; and

generating a switching signal at a control terminal of the switching regulator in response to the sensed first output current or first output voltage.

11. The method of claim 10 further comprising receiving a logic signal corresponding to a USB port type, wherein the first output current is greater than 100 mA and the first input current below a 100 mA when the logic signal is in a first state, and the first output current is greater than 500 mA and the first input current is below 500 mA when the logic signal is in a second state.

12. The method of claim 11 wherein the first input voltage is greater than the voltage on the battery, the first output current to the battery is greater than the first input current, and wherein the first output current is reduced as the first output voltage on the battery increases.

13. The method of claim 11 further comprising storing a charging parameter in a programmable data storage element, wherein the first output current is set by said charging parameter.

14. The method of claim 10 wherein the switching regulator senses the first output voltage and generates a switching signal to control the first output voltage.

15. The method of claim 14 further comprising storing a charging parameter in a programmable data storage element, wherein the first output voltage is set by said charging parameter.

16. A Universal Serial Bus (USB) battery charger comprising:

a switching regulator having a first input coupled to a USB power source, a first output coupled to a battery through a first resistor, and a control input;

a current controller having first and second current sense inputs coupled to first and second terminals of the first resistor for sensing a first output current, and a control output coupled to the control input of the switching regulator; and

a voltage controller having a first voltage sense input coupled to the battery for sensing a first output voltage on the battery, and a control output coupled to the control input of the switching regulator.

17. The battery charger of claim 16 wherein the current controller includes a control input for setting the first output current, and wherein a first logic signal corresponding to a maximum USB current is coupled to the control input of the current controller to set the first output current.

18. The battery charger of claim 17 wherein the current controller sets the first output current to be greater than a first input current received at the first input of the switching regulator.

19. The battery charger of claim 18 wherein the control input of the current controller is coupled to the first input of the switching regulator or the battery, and the current controller reduces the first output current in response to a control signal received at the control input as the voltage on the battery increases.

20. The battery charger of claim 16 further comprising:

a first programmable data storage element coupled to a control input of the current controller for setting the first output current, wherein the first programmable data storage element configures the current controller to supply a first programmed current to said battery if a voltage on said battery is below a first threshold; and

a second programmable data storage element coupled to a control input of the voltage controller for setting the first output voltage, wherein the second programmable data storage element configures the voltage controller to generate a programmed constant voltage to said battery if the voltage on said battery is above the first threshold.