Multiple sensor thermal management for electronic devices

• US 20080123238A1
• Filed: 08/30/2006
• Published: 05/29/2008
• Est. Priority Date: 08/30/2006
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Campos, Marcelo de Paula, Silva Junior, Edevaldo Pereira da, Nascimento, Ivan Carlos Ribeiro do
• Granted Patent: US 7,887,235 B2
• Time in Patent Office: Days
• US Class Current: 361/103
• CPC Class Codes: G01K 3/005 Circuits arrangements for indicating a predetermined temperature fire detection G08B17/00
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A device includes a current source circuit to separately provide a first current and a second current and a thermal detection device coupleable to the output of the current source circuit. The device further includes a voltage detection circuit to provide a first indicator of a first voltage representative of a voltage at the thermal detection device in response to the second current and a second indicator of a second voltage representative of a voltage difference between the voltage at the thermal detection device in response to the second current and a voltage at the voltage detection device in response to the first current. The device further includes a temperature detection circuit to provide an over-temperature indicator based on the first indicator and the second indicator, wherein an operation of a circuit component of the device can be adjusted based on the over-temperature indicator.

Claims

1. A method comprising:

determining a first voltage across a first thermal detection device disposed at a first location of an electronic device in response to a first current at the first thermal detection device at a first time;

determining a second voltage across the first thermal detection device in response to a second current at the first thermal detection device at a second time;

determining a first thermal characteristic of the first location of the electronic device based on a comparison of a third voltage representative of the second voltage to a fourth voltage representative of a difference between the second voltage and the first voltage; and

adjusting, based on the first thermal characteristic and a threshold, an operation of a first circuit component of the electronic device associated with the first location.

2. The method of claim 1, wherein adjusting an operation of the first circuit component comprises at least one of:

disabling an enabled operation of the first circuit component in response to the first thermal characteristic being greater than the threshold; and

enabling a disabled operation of the first circuit component in response to the first thermal characteristic being less than the threshold.

3. The method of claim 1, further comprising:

selecting at least one of the first current and the second current from a plurality of currents so as to adjust the threshold.

4. The method of claim 1, further comprising:

determining the third voltage based on an attenuation of the second voltage by an adjustable attenuation factor, wherein the threshold is based on the adjustable attenuation factor.

5. The method of claim 1, further comprising:

determining the fourth voltage based on an amplification of the difference between the second voltage and the first voltage by an adjustable gain factor, wherein the threshold is based on the adjustable gain factor.

6. The method of claim 1, further comprising:

determining a fifth voltage across a second thermal detection device disposed at a second location of the electronic device in response to a third current at the second thermal detection device at a third time;

determining a sixth voltage across the second thermal detection device in response to a fourth current at the second thermal detection device at a fourth time;

determining a second thermal characteristic of the second location of the electronic device based on a comparison of a seventh voltage representative of the sixth voltage and an eighth voltage representative of a difference between the sixth voltage and the fifth voltage; and

adjusting, based on the second thermal characteristic, an operation of a circuit component of the electronic device associated with the second location.

7. The method of claim 1, further comprising:

determining a fifth voltage across the first thermal detection device in response to a third current at the first thermal detection device at a third time subsequent to the first time and the second time;

determining a sixth voltage across the first thermal detection device in response to a fourth current at the first thermal detection device at a fourth time subsequent to the first time and the second time; and

determining a second thermal characteristic of the first location based on a comparison of a seventh voltage representative of the sixth voltage to a eighth voltage representative of a difference between the sixth voltage and the fifth voltage; and

enabling a disabled operation of a circuit component of the electronic device associated with the first location in response to the second thermal characteristic being less than the threshold.

8. The method of claim 1, wherein the third voltage is the second voltage and wherein the fourth voltage is the difference between the second voltage and the first voltage.

9. The method of claim 1, wherein the first thermal detection device comprises a p-n junction.

10. The method of claim 9, wherein determining the first voltage across the first thermal detection device comprises:

providing the first current to a p-type region of the p-n junction via a first interconnect and a second interconnect at the first time; and

providing a third current to an n-type region of the p-n junction via a third interconnect at the first time, wherein the third current is substantially equal to a current at the second interconnect at the first time and wherein a resistance of the third interconnect is substantially equal to a resistance of the second interconnect.

11. The method of claim 10, wherein determining the second voltage across the first thermal detection device comprises:

providing the second current to the p-type region via the first interconnect and the second interconnect at the second time; and

providing a fourth current to the n-type region via the third interconnect at the second time, wherein the fourth current is substantially equal to a current at the second interconnect at the second time.

12. A device comprising:

a current source circuit having an output to separately provide a first current and a second current;

a first thermal detection device disposed at a first location of the device, the first thermal detection device coupleable to the output of the current source circuit;

a voltage detection circuit comprising an input coupleable to the first thermal detection device and an output to provide;

a first indicator of a first voltage representative of a voltage at the first thermal detection device in response to the second current; and

a second indicator of a second voltage representative of a voltage difference between the voltage at the first thermal detection device in response to the second current and a voltage at the first thermal detection device in response to the first current; and

a temperature detection circuit having an input coupled to the output of the voltage detection circuit and an output to provide a first over-temperature indicator based on the first indicator and the second indicator.

13. The device of claim 12, wherein the temperature detection circuit is configured to:

provide a first state indicator in response to the second voltage being greater than the first voltage; and

provide a second state indicator in response to the second voltage being less than the first voltage.

14. The device of claim 12, wherein the voltage detection circuit comprises at least one of:

an attenuation circuit having an input to receive the voltage at the first thermal detection device in response to the second current and an output to provide the first voltage, wherein an attenuation factor of the attenuation circuit is programmable; and

an amplification circuit having an input to receive the voltage difference and an output to provide the second voltage, wherein a gain factor of the amplification circuit is programmable.

15. The device of claim 12, further comprising:

a second thermal detection device disposed at a second location of the device, the second thermal detection device coupleable to the output of the current source circuit; and

wherein the input of the voltage detection circuit is coupleable to the second thermal detection device;

wherein the output of the voltage detection circuit further is to provide;

a third indicator of a third voltage representative of a voltage at the second thermal detection device in response to the second current; and

a fourth indicator of a fourth voltage representative of a difference between a voltage at the second thermal detection device in response to the second current and a voltage at the second thermal detection device in response to the first current; and

wherein the output of the over-temperature detection circuit further is to provide a second over-temperature indicator based on the third indicator and the fourth indicator.

16. The device of claim 15, wherein an operation of a second circuit component of the device is enabled or disabled based on the second over-temperature indicator

17. The device of claim 12, wherein the voltage detection circuit comprises:

a capacitive element having a first electrode and a second electrode, the first electrode coupleable to the first electrode of the first thermal detection device;

a transistor having a control electrode, a first current electrode coupled to the second electrode of the capacitive element and a second current electrode coupled to the first voltage reference; and

wherein the transistor is configured to be enabled when the current source circuit provides the first current and disabled when the current source provides the second current.

18. The device of claim 17, wherein the temperature detection circuit comprises:

a comparator circuit having a first input coupled to the first electrode of the capacitive element, a second input coupled to the second electrode of the capacitive element, and an output to provide an output voltage based on a comparison of the third voltage to the fourth voltage, wherein the output voltage is representative of the first over-temperature indicator.

19. The device of claim 12, wherein the first thermal detection device comprises a p-n junction.

20. The device of claim 19, wherein:

the p-n junction comprises a p-type region coupleable to the current source circuit via a first interconnect and a second interconnect and an n-type region coupleable to the current source circuit via a third interconnect, wherein a resistance of the third interconnect is substantially equal to a resistance of the second interconnect;

the current source circuit is configured to provide the first current to the p-type region via both the first electrode and the second electrode concurrent with a third current provided to the n-type region via the third electrode, wherein the third current is substantially equal to a current at the second electrode; and

the temperature detection circuit is coupleable to the second interconnect and the third interconnect, wherein the temperature detection circuit is configured to determine the first voltage and the second voltage via the second interconnect and the third interconnect.

21. The device of claim 12, wherein an operation of the first circuit component of the device is enabled or disabled based on the first over-temperature indicator.

22. The device of claim 12, wherein the device comprises an integrated circuit comprising the current source circuit, the first thermal detection device, the voltage detection circuit, and the temperature detection circuit.

24. The method of claim 18, further comprising:

adjusting an operation of a circuit component associated with the location of the device based on the thermal characteristic.

23. In a device comprising a p-n junction disposed at a location of the device, the p-n junction having a p-type region with a first interconnect and a second interconnect coupled thereto and an n-type region with a third interconnect and a fourth interconnect coupled thereto, a method comprising:

during a first phase;

providing a first current to the p-type region via the first interconnect, a second current to the p-type region via the second interconnect, and a third current to the n-type region via the third interconnect, wherein the second current is substantially equal to the third current; and

determining a first voltage across the second interconnect and the third interconnect in response to providing the first current, the second current and the third current; and

during a second phase;

providing a fourth current to the p-type region via the first interconnect, a fifth current to the p-type region via the second interconnect, and a sixth current to the n-type region via the third interconnect, wherein the fifth current is substantially equal to the sixth current; and

determining a second voltage across the second interconnect and the third interconnect in response to providing the fourth current, the fifth current, and the sixth current; and

determining a thermal characteristic of the location of the electronic device based on a comparison of a third voltage representative of the second voltage to a fourth voltage representative of a difference between the second voltage and the first voltage.