MULTIMODE WIRELESS POWER TRANSMITTERS AND RELATED METHODS

1 . A wireless power transmitter, comprising:

a bridge inverter configured to receive a DC power signal and generate an AC power signal according to an operating frequency;

a resonant tank configured to receive the AC power signal and generate an electromagnetic field responsive thereto; and

control logic configured to cause the resonant tank to reconfigure and adjust its resonant frequency for a particular receiver type of a wireless power receiver with which a mutual inductance relationship is desired.

2 . The wireless power transmitter of claim 1 , wherein the resonant tank includes a plurality of capacitors that are controllable by at least one switch to adjust capacitance of the resonant tank.

3 . The wireless power transmitter of claim 2 , wherein the plurality of capacitors are coupled in parallel with each other, wherein at least one parallel path includes the at least one switch.

4 . The wireless power transmitter of claim 1 , wherein the resonant tank includes a plurality of inductors that are controllable by at least one switch to adjust inductance of the resonant tank.

5 . The wireless power transmitter of claim 4 , wherein the plurality of inductors are coupled parallel with each other, wherein at least one parallel path includes the at least one switch.

6 . The wireless power transmitter of claim 4 , wherein the plurality of inductors are coupled in series with each other, wherein the at least one switch is coupled at a node between inductors and with the rectifier.

7 . The wireless power transmitter of claim 1 , wherein the resonant tank includes a plurality of inductors and a plurality of capacitors that are controllable by at least one switch to adjust both capacitance and inductance of the resonant tank.

8 . The wireless power transmitter of claim 1 , wherein the determined receiver type is based, at least in part, on a unique characteristic of a wireless power standard.

9 . The wireless power transmitter of claim 8 , wherein the unique characteristic includes at least one of a digital ping structure, a communication protocol, and an encoding/decoding scheme.

10 . A wireless power apparatus, comprising:

a bridge inverter configured to generate an AC power signal responsive to a DC power signal;

a resonant tank configured to generate an electromagnetic field having an operating frequency responsive to the AC power signal; and

control logic configured to operate a wireless power transmitter as a multimode transmitter having a first mode for wireless power transfer with a first receiver type and a second mode for wireless power transfer with a second receiver type, wherein the resonant tank is configured to exhibit a different resonant frequency for each of the first mode and the second mode.

11 . The wireless power apparatus of claim 10 , wherein the control logic includes a receiver type detector that is configured to determine a receiver type responsive to at least one input, and select a mode associated with the determined receiver type.

12 . The wireless power apparatus of claim 11 , wherein the at least one input is an internal signal within the wireless power transmitter.

13 . The wireless power apparatus of claim 12 , wherein the internal signal indicates a communication response is received from the wireless power receiver.

14 . The wireless power apparatus of claim 11 , wherein the at least one input is a manual user input.

15 . The wireless power apparatus of claim 10 , wherein the control logic is configured to control the bridge inverter according to a first operating frequency during the first mode, and according to a second operating frequency during the second mode.

16 . The wireless power apparatus of claim 10 , wherein the wireless power apparatus is an electronic device that includes the wireless power transmitter, the wireless power transmitter including the bridge inverter, the resonant tank, and the control logic.

17 . A method for operating a multimode wireless power transmitter, the method comprising:

determining a receiver type for a wireless power receiver with which it is desired to establish a mutual inductance relationship for wireless power transfer; and

generating a wireless power signal with a wireless power transmitter having an operating frequency and resonant tank that is adjusted for a particular receiver type.

18 . The method of claim 17 , wherein generating the wireless power signal includes at least one of:

adjusting a capacitance of the resonant tank while maintaining a fixed inductance;

adjusting a inductance of the resonant tank while maintaining a fixed capacitance; and

adjusting both a capacitance an inductance of the resonant tank.

19 . The method of claim 17 , wherein determining the receiver type includes:

transmitting a first communication signal from the wireless power transmitter to the wireless power receiver, the first communication signal having a first characteristic associated with a first receiver type; and

if no response is received by the wireless power transmitter during a waiting period, reconfiguring the resonant tank and operating frequency and transmitting second communication signal from the wireless power transmitter to the wireless power receiver, the second communication signal having a second characteristic associated with a second receiver type.

20 . The method of claim 19 , wherein the first characteristic and the second characteristic differ by at least one of an operating frequency, an encoding/decoding scheme, and ping structure.