Methods, systems and apparatus for determining whether an accessory includes particular circuitry

• US 8,683,090 B2
• Filed: 09/07/2012
• Issued: 03/25/2014
• Est. Priority Date: 04/19/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mullins, Scott, Kosut, Alexei, Terlizzi, Jeffrey J., Rich, Zachary C.
• Primary Examiner(s): SHIN, CHRISTOPHER B
• Application Number:
  US13/607,473
• Publication Number:
  US 20130279055A1
• Time in Patent Office: 564 Days
• Field of Search: 710 15- 19, 710/62, 710/72, 320106-115, 713/300, 713/310
• US Class Current: 710/16
• CPC Class Codes: G01N 27/00 Investigating or analysing materials by the use of electric, electrochemical, or magnetic means G01N3/00 – G01N25/00 take precedence; measurement or testing of electric or magnetic variables or of electric or magnetic properties of materials G01R
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/28 Testing of electronic circuits, e.g. by signal tracer EMC, EMP or similar testing of electronic circuits G01R31/002; testing for short-circuits, discontinuities, leakage or incorrect line connection G01R31/50; checking computers or computer components G06F11/00; checking static stores for correct operation G11C29/00 ; testing receivers or transmitters of transmission systems H04B17/00
• 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 21/44 Program or device authentication
• 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: H02H 3/20 responsive to excess voltage
• CPC Class Codes: H02H 9/02 responsive to excess current current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025
• CPC Class Codes: H02J 4/00 Circuit arrangements for mains or distribution networks not specified as ac or dc
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04M 1/0274 for an electrical connector module
• CPC Class Codes: H04M 1/04 Supports for telephone transmitters or receivers

Abstract

Methods, systems, and apparatus for determining whether an accessory includes particular circuitry. A host device may measure a first voltage and a second voltage received from an accessory, where the voltages are provide through the accessory from a power source. Before measuring the second voltage, the host device may send an instruction to the accessory instructing the accessory to alter an impedance of the power path between the power source and the host device, and the host device may draw at least a threshold amount of current from the power source via the accessory. The host device may then determine whether the accessory includes particular circuitry based on the relationship between the first voltage and the second voltage.

Claims

1. A host device comprising:

a connector including;

a power contact operable to receive a voltage from an accessory, the power contact forming part of a power path between the host device and the accessory; and

a data contact operable to exchange data with the accessory; and

control circuitry coupled to the connector and operable to;

measure a first voltage received from the accessory via the power contact;

send an instruction to the accessory via the data contact, the instruction instructing the accessory to alter an impedance, at the accessory, of the power path between the host device and the accessory;

sink current from the accessory via the power contact;

measure a second voltage received from the accessory via the power contact after sending the instruction instructing the accessory to alter the impedance of the power path and after sinking current from the accessory;

determine whether the accessory includes particular circuitry based on whether the first voltage is different than the second voltage; and

charge the host device using power received at the power contact when it is determined that the accessory includes the particular circuitry.

2. The host device of claim 1 wherein the control circuitry is further operable to determine that the accessory includes the particular circuitry if the first voltage is greater than the second voltage by at least a predetermined amount, and to determine that the accessory does not include the particular circuitry if the first voltage is not greater than the second voltage by at least the predetermined amount.

3. The host device of claim 1 further comprising an internal battery, wherein being operable to charge the host device includes being operable to couple the power contact to the internal battery.

4. The host device of claim 1 wherein the control circuitry is further operable to prevent charging of the host device from power received at the power contact when it is determined that the accessory does not include the particular circuitry.

5. The host device of claim 1 further comprising a current sink coupled to the power contact and the control circuitry, the current sink being operable to sink current from a power source provided at the accessory via the power contact.

6. The host device of claim 1 further comprising a current sink coupled to the power contact and the control circuitry, the current sink being operable to sink current from a power source provided external to the accessory via the power contact.

7. The host device of claim 1 further comprising:

power control circuitry including an overvoltage protection switch and a processor; and

a charge control switch coupled between the power control circuitry and the power contact;

wherein the processor is operable to;

control the charge control switch to control charging of an internal battery of the host device, and

control the overvoltage protection switch to prevent the internal battery from receiving a charging voltage from the power contact when at least one of the first voltage or the second voltage is greater than a predetermined voltage.

8. A method of operating a host device, comprising:

measuring, at a first contact of a host connector associated with a host device, a first voltage received from an accessory, the first voltage being received via the first contact, wherein the first contact forms part of a power path between the host device and the accessory;

sending, by the host device, an instruction to the accessory over a second contact of the host connector to alter an impedance, at the accessory, of the power path between the host device and the accessory;

sinking, by the host device and via the first contact, current from the accessory;

receiving, by the host device and over the first contact, a second voltage from the accessory in response to sending the instruction;

measuring, by the host device at the first contact, after sending the instruction to the accessory to alter the impedance of the power path between the host device and the accessory, and after sinking current from the accessory, the second voltage received from the accessory;

determining, by the host device, whether the accessory includes particular circuitry based on whether the first voltage is different than the second voltage; and

charging the host device using power received at the power contact when it is determined that the accessory includes the particular circuitry.

9. The method of claim 8 wherein sinking current includes sinking current from a power source located at the accessory or external to the accessory.

10. The method of claim 9, wherein the amount of current sinked is sufficient to cause the second voltage to be less than the first voltage when the accessory includes the particular operating circuitry and the particular operating circuitry is operating in a state that alters the impedance of the power path between the host device and the accessory.

11. The method of claim 8 wherein determining whether the accessory includes particular circuitry comprises:

determining that the accessory includes the particular circuitry if the second voltage is less than the first voltage by at least a predetermined amount; and

determining that the accessory does not include the particular circuitry if the second voltage is not less than the first voltage by at least the predetermined amount.

12. The method of claim 8 further comprising:

if the accessory is determined to include the particular circuitry, coupling the first contact to power control circuitry of the host device that is operable to charge the host device using power received from the accessory.

13. The method of claim 8 further comprising:

if the accessory is determined to not include the particular circuitry, preventing the host device from charging using power received from the accessory.

14. The method of claim 8 wherein sending an instruction to the accessory comprises one of:

sending a first instruction instructing the accessory to operate in a first state in which an output voltage from the accessory is substantially unaltered from an input voltage received by the accessory from a power source;

sending a second instruction instructing the accessory to operate in a second state in which the output voltage from the accessory is lower than the input voltage;

or

sending a third instruction instructing the accessory to operate in a third state in which the output voltage is reduced by a predetermined amount from the input voltage.

15. A computer-readable non-transitory storage medium having instructions stored thereon that, when executed by a computer processor, cause the computer processor to perform operations comprising:

measuring, at a first contact of a host connector associated with a host device, a first voltage received from an accessory, the first voltage being received via the first contact, wherein the first contact forms part of a power path between the host device and the accessory;

sending, by the host device, an instruction to the accessory over a second contact of the host connector to alter an impedance, at the accessory, of the power path between the host device and the accessory;

sinking, by the host device and via the first contact, current from the accessory;

receiving, by the host device and over the first contact, a second voltage from the accessory in response to sending the instruction;

measuring, by the host device at the first contact, after sending the instruction to the accessory to alter the impedance of the power path between the host device and the accessory, and after sinking current from the accessory, the second voltage received from the accessory;

determining, by the host device, whether the accessory includes particular circuitry based on whether the first voltage is different than the second voltage; and

charging the host device using power received at the power contact when it is determined that the accessory includes the particular circuitry.

16. The computer-readable non-transitory storage medium of claim 15 wherein sinking current includes sinking current from a power source located at the accessory or external to the accessory.

17. The computer-readable non-transitory storage medium of claim 16, wherein the amount of current sinked is sufficient to cause the second voltage to be less than the first voltage when the accessory includes the particular operating circuitry and the particular operating circuitry is operating in a state that alters the impedance of the power path between the host device and the accessory.

18. The computer-readable non-transitory storage medium of claim 15 wherein determining whether the accessory includes particular circuitry comprises:

determining that the accessory includes the particular circuitry if the second voltage is less than the first voltage by at least a predetermined amount; and

determining that the accessory does not include the particular circuitry if the second voltage is not less than the first voltage by at least the predetermined amount.

19. The computer-readable non-transitory storage medium of claim 15 wherein the operations further comprise:

if the accessory is determined to include the particular circuitry, coupling the first contact to power control circuitry of the host device that is operable to charge the host device using power received from the accessory.

20. The computer-readable non-transitory storage medium of claim 15 wherein the operations further comprise:

if the accessory is determined to not include the particular circuitry, preventing the host device from charging using power received from the accessory.

21. The computer-readable non-transitory storage medium of claim 15 wherein sending an instruction to the accessory comprises one of:

sending a first instruction instructing the accessory to operate in a first state in which an output voltage from the accessory is substantially unaltered from an input voltage received by the accessory from a power source;

sending a second instruction instructing the accessory to operate in a second state in which the output voltage from the accessory is lower than the input voltage;

or

sending a third instruction instructing the accessory to operate in a third state in which the output voltage is reduced by a predetermined amount from the input voltage.