MANAGEMENT OF COMMON MODE NOISE FREQUENCIES IN PORTABLE ELECTRONIC DEVICES

• US 20130121031A1
• Filed: 11/15/2011
• Published: 05/16/2013
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Sims, Nicholas A.
• Granted Patent: US 9,385,589 B2
• Time in Patent Office: Days
• US Class Current: 363/15
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence

Abstract

The disclosed embodiments provide a system that facilitates the use of a portable electronic device. During operation, the system detects a coupling of a power supply to the portable electronic device through a set of wires. Next, the system uses the set of wires to identify a type of the power supply. The system then periodically determines a switching frequency of the power supply based on the type of the power supply and a current drawn from the power supply. Finally, the system uses the switching frequency to facilitate the operation of a touch control in the portable electronic device. For example, if the switching frequency corresponds to a sensing frequency of the touch control, the system may change the sensing frequency to an alternative sensing frequency.

Claims

1. A computer-implemented method for facilitating the use of a portable electronic device, comprising:

detecting a coupling of a power supply to the portable electronic device through a set of wires;

using the set of wires to identify a type of the power supply;

periodically determining a switching frequency of the power supply based on the type of the power supply and a current drawn from the power supply; and

using the switching frequency to facilitate the operation of a touch control in the portable electronic device.

2. The computer-implemented method of claim 1, wherein using the set of wires to identify the type of the power supply involves:

obtaining an identifier corresponding to the type from an analog-to-digital converter (ADC) coupled to the wires.

3. The computer-implemented method of claim 2, wherein the identifier is calculated by the ADC using one or more voltage dividers.

4. The computer-implemented method of claim 2, wherein periodically determining the switching frequency of the power supply based on the type of the power supply and the current drawn from the power supply involves:

using the identifier and the current to obtain the switching frequency from a lookup table.

5. The computer-implemented method of claim 1, wherein using the switching frequency to facilitate the operation of the touch control in the portable electronic device involves:

if the switching frequency corresponds to a sensing frequency of the touch control, changing the sensing frequency to an alternative sensing frequency.

6. The computer-implemented method of claim 1, wherein the set of wires comprises:

a power wire;

one or more data wires; and

a ground wire.

7. The computer-implemented method of claim 1, wherein the touch control is associated with at least one of a touchscreen and a touchpad.

8. A method for operating a power supply for a portable electronic device, comprising:

establishing a communications link between the power supply and the portable electronic device;

using the communications link to identify a type of the portable electronic device;

using the type of the portable electronic device to determine a set of sensing frequencies for a touch control of the portable electronic device; and

managing a switching frequency of the power supply based on the sensing frequencies to reduce common mode noise associated with sensing touch input on the portable electronic device.

9. The method of claim 8, further comprising:

temporarily halting operation of the power supply upon receiving a halt command from the portable electronic device to the power supply, wherein the halted operation further reduces common mode noise associated with sensing touch input on the portable electronic device.

10. The method of claim 9, further comprising:

resuming operation of the power supply upon receiving a resume command from the portable electronic device to the power supply.

11. The method of claim 8, wherein using the type of the portable electronic device to determine the set of sensing frequencies for the touch control involves:

using the type of the portable electronic device to obtain the set of sensing frequencies from a lookup table.

12. The method of claim 8, wherein managing the switching frequency of the power supply based on the sensing frequencies to reduce common mode noise associated with sensing touch input on the portable electronic device involves:

modulating the switching frequency so that the power supply avoids frequency bands associated with the sensing frequencies.

13. A system for facilitating the use of a portable electronic device, comprising:

an interface configured to detect coupling of a power supply to the portable electronic device through a set of wires; and

a management apparatus configured to;

use the set of wires to identify a type of the power supply;

periodically determine a switching frequency of the power supply based on the type of the power supply and a current drawn from the power supply; and

use the switching frequency to facilitate the operation of a touch control in the portable electronic device.

14. The system of claim 13, wherein using the set of wires to identify the type of the power supply involves:

obtaining an identifier corresponding to the type from an analog-to-digital converter (ADC) coupled to the wires.

15. The system of claim 14, wherein periodically determining the switching frequency of the power supply based on the type of the power supply and the current drawn from the power supply involves:

using the identifier and the current to obtain the switching frequency from a lookup table.

16. The system of claim 13, wherein using the switching frequency to facilitate the operation of the touch control in the portable electronic device involves:

if the switching frequency corresponds to a sensing frequency of the touch control, changing the sensing frequency to an alternative sensing frequency.

17. The system of claim 13, wherein the set of wires comprises:

a power wire;

one or more data wires; and

a ground wire.

18. The system of claim 13, wherein the management apparatus correspond to at least one of a processor and a power-management unit (PMU).

19. A system for operating a power supply for a portable electronic device, comprising:

an interface configured to establish a communications link between the power supply and the portable electronic device; and

a microcontroller configured to;

use the communications link to identify a type of the portable electronic device;

use the type of the portable electronic device to determine a set of sensing frequencies for a touch control of the portable electronic device; and

manage a switching frequency of the power supply based on the sensing frequencies to reduce common mode noise associated with sensing touch input on the portable electronic device.

20. The system of claim 19, wherein the microcontroller is further configured to:

temporarily halt operation of the power supply upon receiving a halt command from the portable electronic device, wherein the halted operation further reduces common mode noise associated with sensing touch input on the portable electronic device.

21. The system of claim 20, wherein the microcontroller is further configured to:

resume operation of the power supply upon receiving a resume command from the portable electronic device.

22. The system of claim 19, wherein managing the switching frequency of the power supply based on the sensing frequencies to reduce common mode noise associated with sensing touch input on the portable electronic device involves:

modulating the switching frequency so that the power supply avoids frequency bands associated with the sensing frequencies.

23. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for facilitating the use of a portable electronic device, the method comprising:

detecting a coupling of a power supply to the portable electronic device through a set of wires;

using the set of wires to identify a type of the power supply;

periodically determining a switching frequency of the power supply based on the type of the power supply and a current drawn from the power supply; and

using the switching frequency to facilitate the operation of a touch control in the portable electronic device.

24. The computer-readable storage medium of claim 23, wherein using the set of wires to identify the type of the power supply involves:

obtaining an identifier corresponding to the type from an analog-to-digital converter (ADC) coupled to the wires.

25. The computer-readable storage medium of claim 24, wherein periodically determining the switching frequency of the power supply based on the type of the power supply and the current drawn from the power supply involves:

using the identifier and the current to obtain the switching frequency from a lookup table.

26. The computer-readable storage medium of claim 23, wherein using the switching frequency to facilitate the operation of the touch control in the portable electronic device involves:

if the switching frequency corresponds to a sensing frequency of the touch control, changing the sensing frequency to an alternative sensing frequency.

27. The computer-readable storage medium of claim 23, wherein the set of wires comprises:

a power wire;

one or more data wires; and

a ground wire.