# US 2018/0323607 A1 · Methods and apparatus for battery current monitoring

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- Number: US 2018/0323607 A1
- Document ID: US20180323607A1
- Status: Published application
- Kind: A1
- Application number: 15/587,111
- Filed: 2017-05-04
- Published: 2018-11-08
- Earliest claimed: 2017-05-04
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: Devin Cass; Jorge Zabaco; George D. Beckstein, III
- Web page: https://patentgrep.com/patent/US20180323607A1

## CPC

- H02H 3/093: with timing means {(in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247)}
- H02H 3/087: for DC applications
- 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)

## Abstract

Methods and apparatus are disclosed for battery current monitoring. A current controller can prevent injury from a battery operated wearable device. An isolation switch can interrupt delivery of current of a battery to a load in response to an isolation switch control signal to prevent burn injury to a wearer of the battery operated wearable device. The battery operated wearable device can be wrist wearable or head wearable.

## Claims

### Claim 1

A current controller to prevent injury from a battery operated wearable device comprising:
a battery coupler to couple current of a battery;
a sense resistor in circuit with the battery coupler to generate a voltage from the current of the battery;
a current sense amplifier to sense the voltage of the sense resistor;
an integrator in circuit with an output of the current sense amplifier to integrate the output of the current sense amplifier and to generate an integrator output;
a comparator to compare an overcurrent threshold reference and the integrator output to generate an overcurrent indicator;
control logic to generate an isolation switch control signal in response to the overcurrent indicator; and
an isolation switch to interrupt delivery of the current of the battery to a load in response to the isolation switch control signal to prevent burn injury to a wearer of the battery operated wearable device.

### Claim 2 (depends on 1)

The current controller as in claim 1 in which the isolation switch includes a field effect transistor.

### Claim 3 (depends on 1)

The current controller as in claim 1 in which the battery operated wearable device is wrist wearable or head wearable.

### Claim 4 (depends on 1)

The current controller as in claim 1 in which the control logic is to generate the overcurrent threshold reference.

### Claim 5 (depends on 1)

The current controller as in claim 1 in which the control logic is to generate an integrator reset control signal.

### Claim 6 (depends on 5)

The current controller as in claim 5 in which the integrator includes a reset switch to reset the integrator in response to the integrator reset control signal.

### Claim 7 (depends on 5)

The current controller as in claim 5 in which the control logic is to generate a save system state control signal in response to the overcurrent indicator.

### Claim 8

A method of preventing thermal injury in a wearable device, the method comprising:
sensing current from a battery integrating a signal representative of the current from the battery using an integrator to generate an integrator output;
comparing the integrator output and an overcurrent threshold reference;
generating an overcurrent indicator when the integrator output satisfies the overcurrent threshold reference; and
interrupting the current from the battery in response to the overcurrent indicator to prevent the thermal injury.

### Claim 9 (depends on 8)

The method as in claim 8 including delaying for a cool down period after the interrupting of the current from the battery.

### Claim 10 (depends on 8)

The method as in claim 8 including generating a save system state control signal in response to the overcurrent indicator.

### Claim 11 (depends on 10)

The method as in claim 10 including:
delaying for a save system state period after generating the save system state control signal; and
determining when the delaying for the save system state period is finished, in which the interrupting of the current includes interrupting the current after the save system state period is finished.

### Claim 12 (depends on 8)

The method as in claim 8 in which the interrupting of the current includes generating an isolation switch control signal in response to the overcurrent indicator.

### Claim 13 (depends on 12)

The method as in claim 12 in which the interrupting of the current includes activating an isolation switch in response to the isolation switch control signal.

### Claim 14

A head wearable system to avoid thermal head injury due to overcurrent, the system comprising:
a battery;
a sense resistor to generate a voltage from a current of the battery;
a current sense amplifier having inputs in circuit with the sense resistor to sense the voltage of the sense resistor;
an integrator in circuit with an output of the current sense amplifier to integrate the output of the current sense amplifier and to generate an integrator output;
a reset switch to reset the integrator;
a comparator to compare an overcurrent threshold reference and the integrator output to generate an overcurrent indicator; and
an isolation switch to interrupt the current of the battery based on the overcurrent indicator to avoid the thermal head injury.

### Claim 15 (depends on 14)

The head wearable system as in claim 14 in which the isolation switch includes a field effect transistor.

### Claim 16 (depends on 14)

The head wearable system as in claim 14 including a light emitting diode in which the isolation switch is to interrupt an overcurrent through the light emitting diode.

### Claim 17 (depends on 14)

The head wearable system as in claim 14 including a haptic device in which the isolation switch is to interrupt an overcurrent through the haptic device.

### Claim 18 (depends on 14)

The head wearable system as in claim 14 including control logic to generate a save system state control signal in response to the overcurrent indicator.

### Claim 19 (depends on 18)

The head wearable system as in claim 18 in which the control logic includes a delay timer to delay for a save system state period after the control logic generates the save system state control signal.

### Claim 20 (depends on 19)

The head wearable system as in claim 19 in which the isolation switch is to interrupt the current of the battery after the delay timer delays for the save system state period.

### Claim at position 21

21-25. (canceled)