Reducing the Impact of an Inductive Energy Transfer System on a Touch Sensing Device

• US 20150349539A1
• Filed: 09/30/2014
• Published: 12/03/2015
• Est. Priority Date: 05/30/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Moyer, Todd K., Alves, Jeffrey M., Brzezinski, Makiko K., Jol, Eric S., Thompson, Paul J., Graham, Christopher S., Lewis-Kraus, Micah, Lin, Albert, Zuber, Wesley W., Perez, Yehonatan, Patel, Priyank D., Sauer, Christian M., Hwang, Jim C.
• Granted Patent: US 10,027,185 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 15/02 Reducing interference from electric apparatus by means located at or near the interfering apparatus

Abstract

A transmitter device for an inductive energy transfer system can include a DC-to-AC converter operably connected to a transmitter coil, a first capacitor connected between the transmitter coil and one output terminal of the DC-to-AC converter, and a second capacitor connected between the transmitter coil and another output terminal of the DC-to-AC converter. One or more capacitive shields can be positioned between the transmitter coil and an interface surface of the transmitter device. A receiver device can include a touch sensing device, an AC-to-DC converter operably connected to a receiver coil, a first capacitor connected between the receiver coil and one output terminal of the AC-to-DC converter, and a second capacitor connected between the receiver coil and another output terminal of the AC-to-DC converter. One or more capacitive shields can be positioned between the receiver coil and an interface surface of the receiver device.

Claims

1. A transmitter device for an inductive energy transfer system, the transmitter device comprising:

a DC-to-AC converter operably connected to a transmitter coil, wherein the DC-to-AC converter comprises a full bridge circuit;

a first capacitor connected in series between the transmitter coil and one output terminal of the DC-to-AC converter; and

a second capacitor connected in series between the transmitter coil and another output terminal of the DC-to-AC converter, wherein the first and second capacitors are substantially matched, and wherein an amount of noise produced by the transmitter device and transferred inductively by the transmitter coil is reduced.

2. The transmitter device as in claim 1, further comprising a processing device operably connected to the DC-to-AC converter to control a switching frequency of the DC-to-AC converter.

3. The transmitter device as in claim 1, further comprising a first capacitive shield positioned adjacent to the transmitter coil.

4. The transmitter device as in claim 3, wherein the first capacitive shield comprises a distinct capacitive shield that is positioned between the transmitter coil and an interface surface of the transmitter device.

5. The transmitter device as in claim 4, wherein the first capacitive shield is made of one of a paramagnetic material, a grounded pressure sensitive adhesive, and a grounded flexible printed circuit.

6. The transmitter device as in claim 3, wherein the first capacitive shield is formed on a surface of an interface surface of the transmitter device.

7. The transmitter device as in claim 6, wherein the first capacitive shield comprises a conductive paint.

8. A transmitter device for an inductive energy transfer system, the transmitter device comprising:

a transmitter coil; and

a capacitive shield positioned adjacent to an interface surface of the transmitter device to reduce an amount of noise transferred inductively by the transmitter coil.

9. A receiver device for an inductive energy transfer system, the receiver device comprising:

a touch sensing device;

a receiver coil;

a first capacitor connected in series between the receiver coil and one output terminal of an AC-to-DC converter;

a second capacitor connected in series between the receiver coil and another output terminal of the AC-to-DC converter, wherein the first and second capacitors are substantially matched to reduce an amount of noise the touch sensing device receives when the receiver coil is receiving energy inductively.

10. The receiver device as in claim 9, further comprising a first capacitive shield positioned adjacent to the receiver coil, wherein the capacitive shield reduces an amount of noise transferred to the receiver coil inductively to reduce an amount of noise received by the touch sensing device.

11. The receiver device as in claim 10, wherein the first capacitive shield comprises a distinct capacitive shield that is positioned between the transmitter coil and an interface surface of the transmitter device.

12. The receiver device as in claim 11, wherein the first capacitive shield is made of one of a paramagnetic material, a grounded pressure sensitive adhesive, and a grounded flexible printed circuit.

13. The receiver device as in claim 10, wherein the first capacitive shield is formed on a surface of an interface surface of the transmitter device.

14. The receiver device as in claim 13, wherein the first capacitive shield comprises a conductive paint.

15. The receiver device as in claim 9, wherein the touch sensing device comprises a capacitive touch sensing device.

16. The receiver device as in claim 9, wherein the touch sensing device includes a differential integrator.

17. The receiver device as in claim 16, wherein the receiver device further comprises a processing device adapted to select a stimulation frequency for the touch sensing device based on the amount of noise transferred to the receiver device.

18. A receiver device for an inductive energy transfer system, the receiver device comprising:

a receiver coil; and

a capacitive shield positioned adjacent to an interface surface of the receiver device to reduce an amount of noise received inductively by the receiver coil to reduce an amount of noise received by a touch sensing device.

19. An inductive energy transfer system, comprising:

a transmitter device, comprising;

a transmitter coil; and

a first capacitive shield; and

a receiver device, comprising;

a touch sensing device;

a receiver coil; and

a second capacitive shield, wherein the first capacitive shield is positioned between the transmitter coil and the receiver device and the second capacitive shield is positioned between the receiver coil and the transmitter device, and wherein an amount of noise produced by the transmitter device and transferred to the receiver coil inductively by the transmitter coil is reduced to reduce an amount of noise received by the touch sensing device.

20. The inductive energy transfer system as in claim 19, wherein the touch sensing device includes a differential integrator.

21. The inductive energy transfer system as in claim 20, wherein the receiver device further comprises a processing device adapted to select a stimulation frequency for the touch sensing device based on the amount of noise transferred to the receiver device.