Determining Ambient Temperature Using Transient Device Characteristics

• US 20160146678A1
• Filed: 11/24/2015
• Published: 05/26/2016
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kalyanasundaram, Nagarajan
• Granted Patent: US 10,309,840 B2
• Time in Patent Office: Days
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes
• CPC Class Codes: G01K 13/02 for measuring temperature of moving fluids or granular materials capable of flow
• CPC Class Codes: G01K 7/22 the element being a non-linear resistance, e.g. thermistor G01K7/26 takes precedence
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature

Abstract

Embodiments described herein are directed to determining an ambient temperature of an environment in which a device is operating. In some embodiments, the ambient temperature of the environment is determined by determining an initial temperature of the device and also determining when the temperature of the device reaches a first temperature threshold. When the temperature of the device reaches the first temperature threshold, the device is allowed to cool for a predetermined amount of time. Upon expiration of the amount of time, a change in temperature of the device over the amount of time is detected. The detected change in temperature is then used to determine an ambient temperature of the environment in which the device is operating.

Claims

1. A method for controlling a temperature of a device, comprising:

determining an initial temperature of the device;

applying a temperature stimulus to the device;

determining when the temperature of the device reaches a first temperature threshold as a result of the applied temperature stimulus;

causing the device to cool for a predetermined amount of time by removing the temperature stimulus;

determining a change in temperature of the device upon expiration of the predetermined amount of time;

determining the ambient temperature of an environment in which the device is operating based, at least in part, on the change in temperature; and

adjusting a peak temperature of the device based, at least in part, on the ambient temperature of the environment.

2. The method of claim 1, wherein the temperature stimulus is a charging operation.

3. The method of claim 2, wherein the charging operation is an inductive charging operation.

4. The method of claim 2, further comprising adjusting a current supplied by the charging operation based on the determined ambient temperature of the environment.

5. The method of claim 2, further comprising enabling the device to reach the adjusted peak temperature during the charge operation.

6. The method of claim 1, further comprising determining a time period to apply the temperature stimulus based, at least in part, on the determined ambient temperature of the environment.

7. The method of claim 6, wherein the determined time period to apply the temperature stimulus is based, at least in part, on a temperature curve associated with the device.

8. A method for controlling the temperature of a device, comprising:

determining an initial temperature of the device;

applying a temperature stimulus to the device;

determining when the temperature of the device reaches a first temperature threshold as a result of the temperature stimulus;

causing the device to cool for a predetermined amount of time by removing the temperature stimulus;

determining an amount of time to cool the device from the first temperature threshold to a second temperature threshold;

determining the ambient temperature of an environment in which the device is operating based, at least in part, on the change in temperature; and

adjusting a peak temperature of the device based, at least in part, on the ambient temperature of the environment.

9. The method of claim 8, wherein the temperature stimulus is a charging operation.

10. The method of claim 9, wherein the charging operation is an inductive charging operation.

11. The method of claim 9, further comprising adjusting a current supplied by the charging operation based on the determined ambient temperature of the environment.

12. The method of claim 9, further comprising enabling the device to reach the adjusted peak temperature during the charge operation.

13. The method of claim 12, further comprising determining a time period to apply the temperature stimulus based, at least in part, on the determined ambient temperature of the environment.

14. The method of claim 12, wherein the determined time period to apply the temperature stimulus is based, at least in part, on a temperature curve associated with the device.

15. A device, comprising:

a processing unit;

a thermistor; and

a memory coupled to the processing unit, the memory for storing instructions which, when executed by the processing unit, performs a method for controlling the temperature of a device, the method comprising;

determining, using the thermistor, an initial temperature of the device;

applying a temperature stimulus to the device;

determining, using the thermistor, when the temperature of the device reaches a first temperature threshold as a result of the applied temperature stimulus;

causing the device to cool for a predetermined amount of time by removing the temperature stimulus;

determining a change in temperature of the device upon expiration of the predetermined amount of time;

determining the ambient temperature of an environment in which the device is operating based, at least in part, on the change in temperature; and

adjusting a peak temperature of the device based, at least in part, on the ambient temperature of the environment.

16. The device of claim 15, wherein the temperature stimulus is a charging operation.

17. The device of claim 16, wherein the charging operation is an inductive charging operation.

18. The device of claim 16, further comprising instructions for adjusting a current supplied by the charging operation based on the determined ambient temperature of the environment.

19. The device of claim 15, further comprising instructions for determining a time period to apply the temperature stimulus based, at least in part, on the determined ambient temperature of the environment.

20. The device of claim 19, wherein the determined time period to apply the temperature stimulus is based, at least in part, on a temperature curve associated with the device.

21. A method for determining an ambient temperature of an environment in which a device is operating, comprising:

determining an initial temperature of the device;

determining when the temperature of the device reaches a first temperature threshold;

causing the device to cool for a predetermined amount of time; and

determining a change in temperature of the device upon expiration of the predetermined amount of time, wherein the change in temperature is used to determine the ambient temperature of the environment in which the device is operating.

22. The method of claim 21, further comprising charging a battery of the device upon determining the initial temperature of the device.

23. The method of claim 22, wherein causing the device to cool comprises ceasing to charge the device.

24. The method of claim 21, further comprising adjusting a peak allowable temperature of the device based on the determined ambient temperature of the environment in which the device is operating.

25. The method of claim 24, further comprising enabling the device to reach the adjusted peak temperature during a charge operation.