Systems and methods for providing device-to-device handshaking through a power supply signal

• US 8,812,883 B2
• Filed: 09/15/2012
• Issued: 08/19/2014
• Est. Priority Date: 06/15/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Farrar, Doug, Heyl, Lawrence, Sander, Brian
• Primary Examiner(s): Spittle, Matthew D
• Application Number:
  US13/621,209
• Publication Number:
  US 20130013940A1
• Time in Patent Office: 703 Days
• Field of Search: 713/300, 713/330, 713/340, 710/14, 710/105, 710/303, 710/305, 710/306, 710/316
• US Class Current: 713/300
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 13/4081 Live connection to bus, e.g. hot-plugging current or voltage limitation during live insertion H02H9/004
• CPC Class Codes: G06F 21/81 by operating on the power supply, e.g. enabling or disabling power-on, sleep or resume operations
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Handshaking circuits are provided in a communications cable and in a device operable to be mated with the communications cable. Before a device can utilize the power supply signal of such a communications channel, the two handshaking circuits must sufficiently identify one another over a power supply signal with a decreased voltage. The decreased voltage allows for a cable plug to be provided with a safe, protected power that cannot cause harm to a human. The decreased voltage also reduces the chance that a device can receive a primary power supply signal from the cable before the device sufficiently identifies itself. Accordingly, a laptop may be connected to a portable music player, but the voltage of the power supply signal provided by the laptop to the cable may be decreased on-cable until the handshaking circuit of the portable music player sufficiently performs a handshaking operation with a on-cable handshaking circuit.

Claims

1. A method for informing a second device it is connected to a first device, the method comprising:

receiving a power supply signal, wherein the power supply signal has a first characteristic or a second characteristic;

detecting that the received power supply signal having the first characteristic has been received for at least a pre-determined amount of time;

after detecting that the received power supply signal having the first characteristic has been received for the pre-determined amount of time, providing a series of predetermined current pulses to the power supply signal; and

receiving the power supply signal having the second characteristic while the series of predetermined current pulses are provided on the power supply signal.

2. The method of claim 1, wherein the detecting comprises:

performing a counting operation so long as the received power supply signal has the first characteristic.

3. The method of claim 1, wherein the first characteristic of the power supply signal comprises a current limited, stepped-down voltage power supply signal.

4. The method of claim 1, wherein the second characteristic of the power supply signal comprises a stepped-up voltage power supply signal, wherein the stepped-up voltage power supply signal has a higher voltage level than the first characteristic of the power supply signal.

5. The method of claim 1, wherein the power supply signal having the second characteristic is substantially the same as the received power supply signal.

6. The method of claim 1, wherein the second device is an electronic device with a user interface, and the first device comprises a cable.

7. The method of claim 6, wherein the cable comprises one or more plugs.

8. An electronic device comprising:

an interface for receiving a corresponding connector of another device, the interface including at least one electrical contact for receiving a power supply signal; and

a handshaking circuitry electrically coupled to the at least one electrical contact, the handshaking circuitry operative to;

recognize the power supply signal having a first characteristic of the power supply signal;

in response to recognizing the power supply signal having the first characteristic, provide a validation signal to the power supply signal, wherein the validation signal comprises a series of predetermined current pulses; and

receive the power supply signal having a second characteristic while the validation signal is introduced to the power supply signal.

9. The electronic device of claim 8 further comprising:

non-volatile memory; and

a processor operative to communicate with the non-volatile memory and process one or more applications.

10. The electronic device of claim 9 further comprising:

a user input interface for controlling one or more operations of the device.

11. The electronic device of claim 8, wherein the interface is constructed to receive a multi-region plug.

12. The electronic device of claim 8, wherein the interface is designed to accommodate at least 30 contacts spaced apart in a single row of sequentially numbered contact locations, wherein the sequentially numbered contact locations include digital contact locations, analog contact locations, and ground contact locations.

13. The electronic device of claim 8, wherein the interface is a docking connector having two sets of keying arrangement, a first-make, last break ground contact, and a plurality of contacts arranged in a single row, the plurality of contacts including digital and analog contacts.

14. The electronic device of claim 8, wherein the validation signal is encrypted.

15. The electronic device of claim 8, wherein the handshaking circuitry comprises:

a voltage detector for determining whether the power signal meets a voltage threshold;

a timing circuit, wherein the timing circuit is enabled based on whether the voltage threshold is met and the timing circuit performs a counting operation so long as the voltage threshold is met; and

a pulse generator circuit, wherein the pulse generator circuit provides current pulses to the validation signal after the counting operation is performed for a pre-determined amount of time.

16. The electronic device of claim 8, wherein the first characteristic of the power supply signal comprises a current limited, stepped-down voltage power supply signal.

17. The electronic device of claim 8, wherein the second characteristic of the power supply signal comprises a stepped-up voltage power supply signal, wherein the stepped-up voltage power supply signal has a higher voltage level than the first characteristic of the power supply signal.

18. A system comprising a first circuit, the first circuit comprising:

an input node for receiving a power signal;

a voltage detector for determining whether the power signal meets a voltage threshold;

a timing circuit, wherein the timing circuit is enabled based on whether the voltage threshold is met and the timing circuit performs a counting operation so long as the voltage threshold is met; and

a pulse generator circuit, wherein the pulse generator circuit provides a series of predetermined current pulses to the power signal after the counting operation is performed for a pre-determined amount of time.

19. The system of claim 18, further comprising:

a second circuit for providing the power signal and detecting the current pulses in the power signal.

20. The system of claim 19, further comprising:

a second circuit for providing the power signal, the first circuit is provided on a device, and the second circuit is provided on a cable operable to electrically couple with the device.