WIRELESS CHARGER AND WIRELESS POWER RECEIVER

• US 20160172894A1
• Filed: 12/16/2015
• Published: 06/16/2016
• Est. Priority Date: 12/16/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: KHRIPKOV, Alexander, PAVLOV, Konstantin, ARKHIPENKOV, Vladimir, MAKURIN, Mikhail, OLYUNIN, Nikolay, KIM, Do-won
• Granted Patent: US 10,581,284 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields

Abstract

A wireless charging system and method are provided, that are capable of simultaneously charging multiple mobile devices, providing high power transfer efficiency for multiple mobile devices located at any position and orientation, and minimizing electromagnetic radiation from a transmitting (TX) coil and a receiving (RX) coil. The method and structure reduce electromagnetic interference (EMI) radiation by shunting in-phase currents flowing in a wireless power transmitting unit (TX unit) and a wireless power receiving unit (RX unit) of a wireless charging system.

Claims

1. A wireless charger, comprising:

a transmitting coil;

a shielding element formed of a conductive material; and

an impedance matching circuit configured to connect a power source to the transmitting coil,

wherein the impedance matching circuit comprises at least two capacitors which are connected to the transmitting coil in parallel and are configured to connect the transmitting coil to a ground of the power source and to the shielding element.

2. The wireless charger of claim 1, wherein at least one tap of the transmitting coil is connected to the shielding element and to the ground of the power source.

3. The wireless charger of claim 2, wherein the at least one tap is connected to the shielding element and to the ground of the power source via galvanic or capacitive connection.

4. The wireless charger of claim 3, wherein the capacitive connection is formed by lumped capacitor elements or by mutual capacitance between the at least one tap and the shielding element.

5. The wireless charger of claim 2, wherein the at least one tap comprises a center tap of the transmitting coil.

6. The wireless charger of claim 1, further comprising self-resonant absorbing elements placed between the transmitting coil and the shielding element.

7. The wireless charger of claim 6, wherein resonant frequencies of the self-resonant absorbing elements are tuned to be equal to frequencies of peaks of electromagnetic radiation emitted by the transmitting coil.

8. The wireless charger of claim 1, wherein the shielding element is made of at least one of a copper material and a ferrite material.

9. The wireless charger of claim 1, wherein gaps between conductive turns of the transmitting coil decrease in a direction away from a center area of the transmitting coil.

10. The wireless charger of claim 1, wherein turns of the transmitting coil have maximum curvature radiuses at outer edges of the transmitting coil and minimum curvature radiuses in a center area of the transmitting coil.

11. A wireless power receiver connectable to a battery, the wireless power receiver comprising:

a receiving coil; and

an impedance matching circuit configured to connect the receiving coil to the battery,

wherein the impedance matching circuit comprises at least two capacitors which are connected to the receiving coil in parallel and are configured to connect the receiving coil to a ground of the battery.

12. The wireless power receiver of claim 11, further comprising a shielding element disposed adjacent to the receiving coil and formed of a conductive material.

13. The wireless power receiver of claim 12, wherein the shielding element is made of at least one of a copper material and a ferrite material.

14. The wireless power receiver of claim 11, further comprising:

at least two series capacitors serially connected to the receiving coil and are configured to connect the receiving coil to the battery;

at least two inductors configured to connect each of the at least two series capacitors to the battery; and

at least two capacitors configured to connect a ground of the battery to the at least two series capacitors and the at least two inductors.

15. The wireless power receiver of claim 11, further comprising a rectifier connected to the impedance matching circuit.

16. A wireless charging system, comprising:

a wireless power transmitting unit comprising;

a transmitting coil,

a power source,

a shielding element, and

an impedance matching circuit configured to connect the transmitting coil to the power source, wherein the impedance matching circuit comprises at least two capacitors which are connected to the transmitting coil in parallel and connect the transmitting coil to a ground of the power source and to the shielding element; and

a wireless power receiving unit comprising;

a receiving coil,

a load, and

an impedance matching circuit configured to connect the receiving coil to the load, wherein the impedance matching circuit comprises at least two capacitors which are connected to the receiving coil in parallel and connect the receiving coil to a ground of the load.