Open-circuit impedance control of a resonant wireless power receiver for voltage limiting

• US 10,014,724 B2
• Filed: 09/27/2013
• Issued: 07/03/2018
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Riehl, Patrick Stanley, Satyamoorthy, Anand, Akram, Hasnain
• Primary Examiner(s): Borroto, Alfonso Perez
• Application Number:
  US14/355,212
• Publication Number:
  US 20140246923A1
• Time in Patent Office: 1,740 Days
• Field of Search: 307104
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

A resonant wireless power (RWP) receiver is provided that includes an inductor element that couples with a resonant wireless power source. A capacitor arrangement is coupled to the inductor element altering the open-circuit impedance of the RWP receiver to reduce the ac voltage under certain defined situations. The capacitor arrangement includes a plurality capacitors tuned to a control ac voltage in the RWP receiver.

Claims

1. A resonant wireless power (RWP) receiver comprising:

an inductor element that couples with a resonant wireless power source; and

a capacitor arrangement coupled to the inductor element altering the open-circuit impedance of the RWP receiver to reduce an ac voltage at an input of a rectifier coupled to the capacitor arrangement, the capacitor arrangement being configured to reduce the ac voltage when a voltage of the rectifier exceeds an operating voltage of the rectifier, or when a voltage of a dc-dc converter coupled to the rectifier exceeds an operating voltage of the dc-dc converter, wherein the capacitor arrangement includes a plurality of capacitors tuned to control the ac voltage in the RWP receiver.

2. The RWP receiver of claim 1, wherein the capacitor arrangement comprises a series-parallel circuit having an capacitor that can be switched in to adjust the open-source impedance Zoc.

3. The RWP receiver of claim 1, wherein the capacitor arrangement comprises a parallel-series circuit with a Zoc-adjustment capacitor.

4. The RWP receiver of claim 1 comprising the rectifier.

5. The RWP receiver of claim 4, wherein the capacitor arrangement comprises one or more Zoc-adjustment capacitors switchable to ground.

6. The RWP receiver of claim 1, wherein the capacitor arrangement utilizes one or more switches to control the ac voltage.

7. The RWP receiver of claim 1, wherein the rectifier comprises a synchronous rectifier or diode rectifier.

15. The RWP receiver of claim 6, wherein the one or more switches are open when the voltages of the rectifier and dc-dc converter are both within the respective operating voltage, and the one or more switches are closed to reduce the ac voltage when the voltage of the rectifier exceeds the operating voltage of the rectifier, or when the voltage of the dc-dc converter exceeds the operating voltage of the dc-dc converter.

16. The RWP receiver of claim 6, wherein the one or more switches are closed when the voltages of the rectifier and dc-dc converter are both within the respective operating voltages, and the one or more switches are open to reduce the ac voltage when the voltage of the rectifier exceeds the operating voltage of the rectifier, or when the voltage of the dc-dc converter exceeds the operating voltage of the dc-dc converter.

8. A resonant wireless power (RWP) system comprising:

a source circuit that includes a reflected impedance in series with a source coil; and

a receiver circuit that is coupled to the source circuit using an inductor element, and includes a capacitor arrangement coupled to the inductor element altering the open-circuit impedance of the receiver circuit to reduce an ac voltage at an input of a rectifier coupled to the capacitor arrangement, the capacitor arrangement being configured to reduce the ac voltage when a voltage of the rectifier exceeds an operating voltage of the rectifier, or when a voltage of a dc-dc converter coupled to the rectifier exceeds an operating voltage of the dc-dc converter, wherein the capacitor arrangement includes a plurality of capacitors tuned to control the ac voltage in the receiver circuit.

9. The RWP system of claim 8, wherein the capacitor arrangement comprises a series-parallel circuit having a capacitor that can be switched in to adjust the open-source impedance Zoc.

10. The RWP system of claim 8, wherein the capacitor arrangement comprises a parallel-series circuit with a Zoc-adjustment capacitor.

11. The RWP system of claim 8 comprising the rectifier.

12. The RWP system of claim 11, wherein the capacitor arrangement comprises one or more Zoc-adjustment capacitors switchable to ground.

13. The RWP system of claim 8, wherein the capacitor arrangement utilizes one or more switches to control the ac voltage.

14. The RWP system of claim 8, wherein the rectifier comprises a synchronous rectifier or diode rectifier.

17. The RWP system of claim 13, wherein the one or more switches are open when the voltages of the rectifier and dc-dc converter are both within the respective operating voltages, and the one or more switches are closed to reduce the ac voltage when the voltage of the rectifier exceeds the operating voltage of the rectifier, or when the voltage of the dc-dc converter exceeds the operating voltage of the dc-dc converter.

18. The RWP system of claim 13, wherein the one or more switches are closed when the voltages of the rectifier and dc-dc converter are both within the respective operating voltages, and the one or more switches are open to reduce the ac voltage when the voltage of the rectifier exceeds the operating voltage of the rectifier, or when the voltage of the dc-dc converter exceeds the operating voltage of the dc-dc converter.