System and method for inductively charging a battery

• US 8,872,472 B2
• Filed: 09/25/2013
• Issued: 10/28/2014
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Philips IP Ventures B.V. (Koninklijke Philips N.V.)
• Original Assignee: Access Business Group International LLC (Alticor Incorporated)
• Inventors: Baarman, David W., Lord, John J., Stien, Nathan P.
• Primary Examiner(s): Muralidar, Richard V
• Application Number:
  US14/036,434
• Publication Number:
  US 20140021911A1
• Time in Patent Office: 398 Days
• Field of Search: 320/108, 320/163
• US Class Current: 320/108
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

An inductive charging system for recharging a battery. The system includes a charger circuit and a secondary circuit. The secondary circuit includes a feedback mechanism to provide feedback to the charger circuit through the inductive coupling of the primary coil and the secondary coil. The charger circuit includes a frequency control mechanism for controlling the frequency of the power applied to the primary coil at least partly in response to the feedback from the feedback mechanism.

Claims

1. An inductive power supply system comprising:

a primary circuit including a power source, a controller electrically coupled to said power source and a primary electrically coupled to said controller, wherein said controller applies power with a frequency to said primary from said power source;

a portable device separable from said primary circuit and having a secondary circuit and a feedback circuit electrically coupled to said secondary, said secondary circuit includes a secondary inductively coupled to said primary to receive power therefrom, said feedback circuit configured to selectively shunt current from said secondary through an impedance element, wherein in response to current being selectively shunted through said impedance element, a current flow through said secondary increases generating a single surge in current through said primary via said inductive coupling;

wherein said feedback circuit is configured to detect one or more conditions in said portable device, wherein in response to detecting said one or more conditions, said feedback circuit selectively shunts current through said impedance element to generate said single surge in said primary;

wherein said primary circuit includes a feedback detector operably coupled to said controller, wherein said feedback detector is configured to sense said single surge in said primary; and

wherein said controller is configured to recognize said single surge in said primary as an indication of said one or more conditions being detected, whereby said controller is capable of identifying a state of said one or more conditions in said portable device in response to detection of said single surge in said primary.

2. The inductive charging system according to claim 1 wherein said controller controls a characteristic of said power applied to said primary at least partially in response to said single surge generated by said feedback circuit.

3. The inductive charging system according to claim 2 wherein said characteristic of said power is said frequency of power applied to said primary.

4. The inductive charging system according to claim 1 wherein said current flow increasing through said secondary varies a reflected impedance of said secondary circuit.

5. The inductive charging system according to claim 1 wherein said one or more conditions are conditions of said portable device.

6. The inductive charging system according to claim 5 wherein said one or more conditions include at least one of an over-current condition and an over-voltage condition, wherein said feedback circuit includes an over-voltage detector and an over-current detector arranged to control a switch, wherein, in response to an over-voltage condition or an over-current condition of a battery of said portable device, said switch is actuated and current from said secondary is shunted through said impedance element.

7. The inductive charging system according to claim 6 wherein said controller adjusts said frequency of said power applied to said primary to correct at least one of said over-voltage condition and said over-current condition.

8. The inductive charging system according to claim 1 wherein said feedback detector is a current sensor, wherein in response to said current being shunted through said impedance element to generate said single surge in said primary, said current sensor detects said single surge in said primary.

9. The inductive charging system according to claim 1 wherein said feedback detector is a peak detector that provides a detection signal to said controller in response to detecting said single surge in said primary.

10. The inductive charging system according to claim 1 wherein said controller includes an inverter, wherein an operating frequency of said inverter is reduced to move said frequency of said power applied to said primary closer to a resonant frequency of said primary and wherein said operating frequency of said inverter is increased to move said frequency of said power applied to said primary away from said resonant frequency of said primary.

11. A method for communicating from a portable device to an inductive power supply, the inductive power supply including a primary circuit having a power source and a controller coupled to the power source, the controller controlling the supply of power from the power source to a primary of the inductive power supply, the portable device being separable from the inductive power supply and having a secondary and a feedback circuit electrically coupled to the secondary, the feedback circuit of the portable device including an impedance element capable of being selectively controlled to shunt current from the secondary to generate a single surge in current in the primary of the inductive power supply, said method comprising:

associating the single surge in the primary with one or more conditions in the portable device;

operating the inductive power supply to inductively couple the primary with the secondary the portable device, wherein power is supplied from the power source to the primary at a frequency;

detecting one or more conditions in the portable device, and, in response detecting the one or more conditions, selectively shunting current through the impedance element to generate the single surge in current in the primary of the inductive power supply; and

determining, in the inductive power supply, a state of the one or more conditions in the portable device based on an occurrence of the single surge in the primary.

12. The method according to claim 11 wherein further comprising adjusting a characteristic of power applied to the primary in response to the occurrence of the single surge in the primary.

13. The method according to claim 12 wherein the characteristic of power is the frequency of power supplied to the primary.

14. The method according to claim 11 wherein the one or more conditions are defined as at least one of an over-voltage condition and an over-current condition according to a charging profile of a battery of the portable device;

and wherein said method further comprises the steps of;

generating the single surge in the primary by selectively shunting current through the impedance element in response to at least one of the over-voltage and the over-current condition being met; and

adjusting the frequency of the power applied to the primary in response to the occurrence of the single surge.

15. The method according to claim 11 wherein the one or more conditions are conditions of the portable device.

16. The method according to claim 11 further comprising detecting, in the inductive power supply, the occurrence of the single surge in the primary.

17. The method according to claim 11 further comprising adjusting the frequency of power applied to the primary to control the amount of power transferred to the secondary, wherein the frequency of power applied to the primary is increased to move farther resonance, and wherein the frequency of power applied to the primary is decreased to move closer to resonance.

18. A portable electronic device being separable from an inductive power supply, the inductive power supply having a primary configured to transfer power inductively, said portable electronic device comprising:

a secondary configured to receive power inductively from the primary via an inductive coupling, wherein a reflected impedance of said portable electronic device is reflected to the inductive power supply through said inductive coupling;

a feedback circuit electrically coupled to said secondary, said feedback circuit having an impedance element configured to be selectively controlled to shunt current from said secondary, wherein in response to current being selectively shunted from said secondary through said impedance element, said secondary generates a single surge in said reflected impedance of said portable electronic device; and

wherein said feedback circuit is configured to detect one or more conditions in said portable device, wherein in response to detecting said one or more conditions, said feedback current selectively shunts current through said impedance element to generate said single surge in said reflected impedance, wherein said single surge communicates to the inductive power supply a state of said one or more conditions in said portable electronic device.

19. The portable electronic device as claimed in claim 18 wherein said one or more conditions are conditions of said portable electronic device.

20. The portable electronic device as claimed in claim 18 wherein said one or more conditions include at least one of an over-voltage condition and an over-current condition of a battery of said portable electronic device.

21. The portable electronic device as claimed in claim 18 wherein said single surge communicates a change in said state of said one or more conditions in said portable electronic device.