Method for performing wireless charging control with aid of admittance detection, and associated apparatus

• US 9,685,815 B2
• Filed: 12/03/2014
• Issued: 06/20/2017
• Est. Priority Date: 01/16/2014
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Lee, Chi-Min
• Primary Examiner(s): Whitmore, Stacy
• Application Number:
  US14/559,884
• Publication Number:
  US 20150198640A1
• Time in Patent Office: 930 Days
• Field of Search: 320108
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A method for performing wireless charging control and an associated apparatus are provided, where the method may include: performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter; generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes may include a power loss index indicating power loss of a wireless charging operation performed by the wireless charging transmitter, and may further include an admittance-related index corresponding to any of a ratio of the driving current to the driving voltage or a reciprocal of the ratio of the driving current to the driving voltage; and performing wireless charging foreign object detection (FOD) according to the set of indexes.

Claims

1. A method for performing wireless charging control, the method being applied to a wireless charging transmitter, the method comprising the steps of:

performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter;

generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes comprises a power loss index indicating power loss of a wireless charging operation performed by the wireless charging transmitter, and further comprises an admittance-related index corresponding to any of a ratio of the driving current to the driving voltage or a reciprocal of the ratio of the driving current to the driving voltage; and

performing wireless charging foreign object detection (FOD) according to the set of indexes.

2. The method of claim 1, wherein the step of generating the set of indexes at least according to the driving current and the driving voltage further comprises:

determining charging power output from the wireless charging transmitter according to the driving current and the driving voltage;

determining received power of at least one wireless charging receiver according to at least one received power report obtained from the at least one wireless charging receiver; and

generating the power loss index according to the charging power output from the wireless charging transmitter and according to the received power of the at least one wireless charging receiver.

3. The method of claim 1, wherein in a situation where the admittance-related index corresponds to the ratio of the driving current to the driving voltage, the step of generating the set of indexes at least according to the driving current and the driving voltage further comprises:

determining received power of at least one wireless charging receiver according to at least one received power report obtained from the at least one wireless charging receiver;

determining a normalized transmitter admittance parameter corresponding to the received power of the at least one wireless charging receiver according to a predetermined relationship between the normalized transmitter admittance parameter and the received power of the at least one wireless charging receiver; and

calculating a difference between the ratio of the driving current to the driving voltage and the normalized transmitter admittance parameter to generate the admittance-related index.

4. The method of claim 1, wherein in a situation where the admittance-related index corresponds to the reciprocal of the ratio of the driving current to the driving voltage, the step of generating the set of indexes at least according to the driving current and the driving voltage further comprises:

determining received power of at least one wireless charging receiver according to at least one received power report obtained from the at least one wireless charging receiver;

determining a normalized transmitter impedance parameter corresponding to the received power of the at least one wireless charging receiver according to a predetermined relationship between the normalized transmitter impedance parameter and the received power of the at least one wireless charging receiver; and

calculating a difference between the reciprocal of the ratio of the driving current to the driving voltage and the normalized transmitter impedance parameter to generate the admittance-related index.

5. The method of claim 1, wherein the set of indexes further comprises a current-related index corresponding to the driving current, wherein the current-related index is different from the admittance-related index.

6. The method of claim 5, wherein the step of generating the set of indexes at least according to the driving current and the driving voltage further comprises:

determining received power of at least one wireless charging receiver according to at least one received power report obtained from the at least one wireless charging receiver;

determining a normalized transmitter current parameter corresponding to the received power of the at least one wireless charging receiver according to a predetermined relationship between the normalized transmitter current parameter and the received power of the at least one wireless charging receiver; and

calculating a difference between the driving current and the normalized transmitter current parameter to generate the current-related index.

7. The method of claim 1, wherein the step of performing the wireless charging FOD according to the set of indexes further comprises:

determining a set of threshold corresponding to a set of FOD strategy control parameters according to a predetermined relationship between the set of threshold and the set of FOD strategy control parameters;

comparing the set of indexes with the set of threshold to generate a set of comparison results, respectively; and

generating a wireless charging control signal according to the set of comparison results, for controlling whether to temporarily stop wireless charging or not.

8. The method of claim 7, wherein the step of performing the wireless charging FOD according to the set of indexes further comprises:

generating a warning control signal according to at least one portion of comparison results within the set of comparison results, wherein the warning control signal is utilized for controlling a warning user interface (UI) of the wireless charging transmitter to indicate whether a foreign object is a dangerous foreign object or a non-dangerous foreign object.

9. The method of claim 7, wherein the set of FOD strategy control parameters comprises a received power parameter, wherein the received power parameter corresponds to received power of at least one wireless charging receiver.

10. The method of claim 9, wherein the set of FOD strategy control parameters further comprises a wireless charging receiver count parameter, wherein the wireless charging receiver count parameter represents a number of wireless charging receivers within the at least one wireless charging receiver.

11. The method of claim 10, wherein the set of FOD strategy control parameters further comprises at least one device type parameter, wherein the at least one device type parameter corresponds to a transmitter type of the wireless charging transmitter or at least one receiver type of the at least one wireless charging receiver.

12. The method of claim 10, wherein a specific wireless charging receiver within the at least one wireless charging receiver determines at least one random value for controlling timing of packet transmission regarding at least one wireless charging report of the specific wireless charging receiver;

based on the at least one random value, the specific wireless charging receiver sends at least one random phase-delay packet, wherein each random phase-delay packet of the at least one random phase-delay packet has a random phase-delay with respect to a time slot, and the at least one random phase-delay packet is utilized for carrying information of the at least one wireless charging report; and

the step of performing the wireless charging FOD according to the set of indexes further comprises;

accumulating packet information of a plurality of packets in a predefined period to generate an accumulation value, wherein the plurality of packets comprises the at least one random phase-delay packet sent by the specific wireless charging receiver, and a length of the predefined period is greater than or equal to twice a length of the time slot; and

determining the wireless charging receiver count parameter according to the accumulation value.

13. The method of claim 12, wherein the step of determining the wireless charging receiver count parameter according to the accumulation value further comprises:

performing at least one filtering operation on the accumulation value to generate the wireless charging receiver count parameter.

14. The method of claim 1, wherein the step of performing the wireless charging FOD according to the set of indexes further comprises:

accessing a FOD control database that is prepared in advance, wherein the FOD control database indicates at least one predetermined zone on a coordinate plane of (Rx_power, Tx_admittance), in which the coordinate Rx_power represents received power of at least one wireless charging receiver and the coordinate Tx_admittance represents the ratio of the driving current to the driving voltage, and the at least one predetermined zone corresponds to dangerous foreign objects or non-dangerous foreign objects; and

based on the FOD control database, determining whether to temporarily stop wireless charging or not according to the received power of the at least one wireless charging receiver and the ratio of the driving current to the driving voltage.

15. The method of claim 1, wherein the set of indexes is generated in a steady state regarding the wireless charging operation performed by the wireless charging transmitter;

and the method further comprises;

performing at least one steady state detection within the wireless charging transmitter to guarantee that the set of indexes is generated in the steady state.

16. The method of claim 1, further comprising:

generating another set of indexes at least according to the driving current and the driving voltage, wherein the other set of indexes comprises a current index indicating the driving current, and further comprises an admittance index indicating the ratio of the driving current to the driving voltage;

wherein the step of performing the wireless charging FOD according to the set of indexes further comprises;

performing the wireless charging FOD according to the set of indexes and according to the other set of indexes.

17. The method of claim 16, wherein the step of performing the wireless charging FOD according to the set of indexes and according to the other set of indexes further comprises:

when the other set of indexes indicates that a dangerous foreign object is detected, immediately stopping wireless charging and temporarily preventing utilizing the set of indexes.

18. An apparatus for performing wireless charging control, the apparatus comprising

at least one portion of a wireless charging transmitter, the apparatus comprising:

at least one detection circuit, arranged for performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter;

a set of index generating circuits, coupled to the at least one detection circuit, arranged for generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes comprises a power loss index indicating power loss of a wireless charging operation performed by the wireless charging transmitter, and further comprises an admittance-related index corresponding to any of a ratio of the driving current to the driving voltage or a reciprocal of the ratio of the driving current to the driving voltage; and

a foreign object detection (FOD) strategy module, coupled to the set of index generating circuits, arranged for performing wireless charging FOD according to the set of indexes.

19. A method for performing wireless charging control, the method being applied to a wireless charging transmitter, the method comprising the steps of:

performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter;

generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes comprises a power loss index indicating power loss of a wireless charging operation performed by the wireless charging transmitter, and further comprises a current-related index corresponding to the driving current, wherein generating the set of indexes at least according to the driving current and the driving voltage comprises;

determining received power of at least one wireless charging receiver according to at least one received power report obtained from the at least one wireless charging receiver;

determining a normalized transmitter current parameter corresponding to the received power of the at least one wireless charging receiver according to a predetermined relationship between the normalized transmitter current parameter and the received power of the at least one wireless charging receiver; and

calculating a difference between the driving current and the normalized transmitter current parameter to generate the current-related index; and

performing wireless charging foreign object detection (FOD) according to the set of indexes.

20. A method for performing wireless charging control, the method being applied to a wireless charging transmitter, the method comprising the steps of:

performing current detection and voltage detection to monitor a driving current and a driving voltage within the wireless charging transmitter, respectively, wherein the driving current and the driving voltage are utilized for driving a power output coil of the wireless charging transmitter;

generating a set of indexes at least according to the driving current and the driving voltage, wherein the set of indexes comprises an admittance-related index corresponding to any of a ratio of the driving current to the driving voltage or a reciprocal of the ratio of the driving current to the driving voltage, and further comprises a current-related index corresponding to the driving current; and

performing wireless charging foreign object detection (FOD) according to the set of indexes.