# US 2013/0278205 A1 · Methods, systems and apparatus for determining whether an accessory includes particular circuitry

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- Number: US 2013/0278205 A1
- Document ID: US20130278205A1
- Status: Published application
- Kind: A1
- Application number: 13/730,667
- Filed: 2012-12-28
- Published: 2013-10-24
- Earliest claimed: 2012-04-19
- Assignees: Apple Inc.
- Applicants: Apple Inc.
- Inventors: Scott Mullins; Alexei Kosut; Jeffrey J. Terlizzi; Zachary C. Rich
- Web page: https://patentgrep.com/patent/US20130278205A1

## CPC

- 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)
- G01R 19/0084: {Measuring voltage only}
- 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})
- 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}
- G06F 21/44: Program or device authentication
- G06F 21/81: by operating on the power supply, e.g. enabling or disabling power-on, sleep or resume operations
- H02H 3/20: responsive to excess voltage
- H02H 9/02: responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)}
- H02J 4/00: Circuit arrangements for mains or distribution networks not specified as AC or DC; Circuit arrangements for mains or distribution networks combining AC and DC sections or sub-networks (arrangements using intermediate DC-AC-DC conversion H02J1/002; arrangements using high-voltage DC [HVDC] links H02J3/36)
- H02J 7/64: against overvoltage
- H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)}
- H02J 7/42: with electronic devices having internal batteries, e.g. mobile phones
- H02J 7/47: Arrangements for checking compatibility or authentication between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
- H02J 7/70: characterised by the mechanical construction
- H04M 1/0274: {for an electrical connector module}
- H04M 1/04: Supports for telephone transmitters or receivers
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)

## 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

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

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

The host device of claim 1 wherein the control circuitry is further operable to charge the host device using power received at the power contact when it is determined that the accessory includes the particular circuitry.

### Claim 4 (depends on 3)

The host device of claim 3 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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 1)

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.

### Claim 9

A method of determining whether an accessory includes particular circuitry, comprising:
measuring, at a first contact of a host connector associated with a host device, a first voltage received from the 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; and
determining, by the host device, whether the accessory includes particular circuitry based on whether the first voltage is different than the second voltage.

### Claim 10 (depends on 9)

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

### Claim 11 (depends on 10)

The method of claim 10, 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.

### Claim 12 (depends on 9)

The method of claim 9 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.

### Claim 13 (depends on 9)

The method of claim 9 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.

### Claim 14 (depends on 9)

The method of claim 9 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.

### Claim 15 (depends on 9)

The method of claim 9 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.

### Claim 16

An accessory comprising:
a power pin operable to provide a voltage to a host device;
a data pin operable to receive an instruction from the host device; and
power limiting circuitry configured to implement:
a bypass mode of operation in which current and voltage may pass through the power limiting circuitry from a power source to the power pin substantially unaltered, and
a power limiting mode of operation in which an impedance of the power limiting circuitry is increased compared to when operating in the bypass mode of operation so as to reduce a first voltage received from the power source to a second voltage provided at the power pin;
wherein the power limiting circuitry switches from the bypass mode of operation to the power limiting mode of operation in response to receiving an instruction from the host device over the data pin.

### Claim 17 (depends on 16)

The accessory of claim 16 wherein the power limiting circuitry includes identification circuitry and impedance altering circuitry, the impedance altering circuitry being arranged between the power source and the power pin and being configured to operate in the bypass mode of operation and the power limiting mode of operation, the identification circuitry being coupled to the impedance altering circuitry and the data pin.

### Claim 18 (depends on 17)

The accessory of claim 17 wherein the identification circuitry is operable to instruct the impedance altering circuitry to operate in the power limiting mode of operation so as to disable a power path between the power source and the host device via the power pin in response to receiving power from the host device over the data pin.

### Claim 19 (depends on 18)

The accessory of claim 18 wherein the identification circuitry is further operable to:
read a request for an accessory identifier received from the host device over the data pin while the power limiting circuitry is in the power limiting mode of operation;
determine whether the request for the accessory identifier is valid; and
instruct the impedance altering circuitry to switch its mode of operation from the power limiting mode of operation to the bypass mode of operation so as to enable the power path between the power source and the host device via the data pin in response to determining that the request for the accessory identifier is valid.

### Claim 20 (depends on 17)

The accessory of claim 17 wherein the identification circuitry is operable to:
receive an instruction from the host device over the data pin;
determine whether the instruction is an instruction to alter an impedance of a power path between the power source and the host device; and
cause the impedance altering circuitry to operate in one of the bypass mode of operation or the power limiting mode of operation so as to alter the impedance of the power path between the power source and the host device via the power pin in response to determining that the instruction is an instruction to alter the impedance of the power path between the power source and the host device.

### Claim 21 (depends on 16)

The accessory of claim 16 wherein the power limiting circuitry operates in the bypass mode of operation in response to the accessory establishing a physical connection with the host device.

### Claim 22 (depends on 21)

The accessory of claim 21 wherein the power limiting circuitry operates in the bypass mode of operation until receiving a voltage from the host device over the data pin, and the power limiting circuitry switches its mode of operation from the bypass mode of operation to the power limiting mode of operation in response to receiving a positive voltage from the host device over the data pin.

### Claim 23 (depends on 16)

The accessory of claim 16 wherein the power limiting circuitry, when in the power limiting mode of operation, has a voltage/current characteristic such that the power limiting circuitry outputs a positive voltage an amount of current passing through the power limiting circuitry is less than a threshold amount of current and outputs approximately zero voltage when the amount of current passing through the power limiting circuitry meets or exceeds the threshold amount of current.

### Claim 24

A method of operating an accessory, comprising:
receiving, at the accessory, an instruction from a host device, the instruction being received over a data pin of the accessory, the data pin being coupled to identification circuitry of the accessory;
determining, by the identification circuitry, whether the instruction is an instruction to alter an impedance of a power path between a power source and the host device, the power path between the power source and the host device including power limiting circuitry disposed between the power source and the host device and coupled to the identification circuitry; and
altering the impedance of the power path between the power source and the host device by sending a control signal from the identification circuitry to the power limiting circuitry that causes the power limiting circuitry to change its mode of operation between a bypass mode of operation and a power limiting mode of operation when it is determined that the instruction is an instruction to alter the impedance of the power path between the power source and the host device.

### Claim 25 (depends on 24)

The method of claim 24, wherein altering the impedance of the power path includes increasing or decreasing the impedance of the power path between the power source and the host, the impedance of the power path being increased when the power limiting circuitry changes its mode of operation from the bypass mode of operation to the power limiting mode of operation, and the impedance of the power path being decreased when the power limiting circuitry changes its mode of operation from the power limiting mode of operation to the bypass mode of operation.

### Claim 26 (depends on 25)

The method of claim 25, wherein the impedance of the power path is increased only when an amount of current passing through the power limiting circuitry exceeds a threshold amount of current.

### Claim 27 (depends on 24)

The method of claim 24, further comprising:
determining whether the accessory is mated with the host device; and
in response to determining that the accessory is mated with the host device, operating the power limiting circuitry in the bypass mode of operation so as to enable the power path between the power source and the host device.

### Claim 28 (depends on 27)

The method of claim 27, further comprising:
determining whether power is received from the host device via the data pin of the accessory; and
in response to determining that power is received from the host device via the data pin of the accessory, operating the power limiting circuitry in the power limiting mode of operation so as to disable the power path between the power source and the host device.

### Claim 29 (depends on 28)

The method of claim 28, further comprising:
receiving a request for an accessory identifier from the host device over the data pin of the accessory;
determining whether the request for the accessory identifier is valid; and
upon determining that the request for the accessory identifier is valid:
operating the power limiting circuitry in the bypass mode of operation so as to enable the power path between the power source and the host device; and
communicating the accessory identifier to the host device via the data pin.

### Claim 30 (depends on 29)

The method of claim 29, further comprising:
receiving an instruction to disable the power path between the power source and the host device; and
in response to receiving the instruction to disable the power path between the power source and the host device, operating the power limiting circuitry in the power limiting mode of operation so as to disable the power path between the power source and the host device.