Temperature sensing circuit

• US 20050099752A1
• Filed: 11/08/2003
• Published: 05/12/2005
• Est. Priority Date: 11/08/2003
• Status: Active Grant

• Current Assignee: ThinkLogix, LLC (Ascend Innovation Management, LLC)
• Original Assignee: Andigilog, Inc. (Microchip Technology Incorporated)
• Inventors: Aykroyd, Craig M., McLin, Jonathan Daniel, Liepold, Carl F.
• Granted Patent: US 7,857,510 B2
• Time in Patent Office: Days
• US Class Current: 361/103
• CPC Class Codes: G01K 17/06 Measuring quantity of heat conveyed by flowing media, e.g. in heating systems G01K17/02, G01K17/04 take precedencee.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device
• CPC Class Codes: G01K 3/005 Circuits arrangements for indicating a predetermined temperature fire detection G08B17/00

Abstract

A temperature sensor, in accordance with the principles of the invention comprises a silicon substrate. The silicon substrate includes a bandgap, an offset circuit for providing calibration offsets, and a gain block for providing an output that varies substantially linearly with changes in temperature of the substrate.

Claims

1. A temperature sensor, comprising:

a silicon substrate, said silicon substrate having formed thereon;

a bandgap;

an offset circuit for providing calibration offsets; and

a gain block for providing an output that varies substantially linearly with changes in temperature of said substrate.

2. A temperature sensor in accordance with claim 1, comprising:

first and second terminals formed on said substrate;

a transistor coupled between said first and second terminals and having a control input coupled to said gain block.

3. A temperature sensor in accordance with claim 1, comprising:

a current source formed on said silicon substrate for providing current to said bandgap and to said gain block.

4. A temperature sensor in accordance with claim 1, wherein:

said offset circuit comprises one or more resistance values and fusible links for permanently selecting one of said resistance values.

5. A temperature sensor in accordance with claim 1, wherein:

said offset circuit comprises a calibration circuit, said calibration circuit being operable to set said offset circuit to a desired offset.

6. A temperature sensor in accordance with claim 1, comprising:

first and second terminals formed on said substrate;

said gain block and said bandgap being coupled to said first and second terminals; and

a third terminal formed on said substrate;

said gain block having an output coupled to said third terminal.

7. A temperature sensor in accordance with claim 1, wherein:

said offset block comprising a plurality of resistors formed in said silicon substrate, and a programmable link structure configurable to provide a predetermined offset such that said temperature sensor is permanently calibrated.

8. A temperature sensor in accordance with claim 3, comprising:

one or more resistors formed in said substrate, said one or more resistors comprising a pinched well configuration, said pinched well configuration comprising a well and a layer formed on said well;

said well comprising a first polarity material formed in said substrate;

said layer comprising a second polarity material formed on said well; and

said layer being in electrical cascade connection with said well.

9. A temperature sensor, comprising:

a silicon substrate, said silicon substrate having formed thereon a bandgap, an offset circuit for providing calibration offsets; and

a gain block;

said offset block comprising a plurality of resistors formed in said silicon substrate, and a programmable link structure configurable to provide a predetermined offset such that said temperature sensor is permanently calibrated.

10. A temperature sensor in accordance with claim 9, wherein:

said programmable link structure comprises selectable fusible links.

11. A temperature sensor in accordance with claim 9, comprising:

a startup circuit operable to control operation of at least one of said band gap and said gain block to provide controlled operation of said temperature sensor when power is applied to said temperature sensor.

12. A temperature sensor in accordance with claim 9 comprising:

a current source for providing current to said bandgap and to said gain block.

13. A temperature sensor in accordance with claim 9, comprising:

a buffer disposed between said bandgap and said gain block.

14. A temperature sensor in accordance with claim 9, comprising:

first and second terminals disposed on said substrate; and

a load coupled between said first and second terminals, said gain block controlling said load in dependence on the temperature of said substrate.

15. A temperature sensor in accordance with claim 9, comprising:

first and second terminals disposed on said substrate; and

a field effect transistor coupled between said first and second terminals and controlled by said gain block.

16. A temperature sensor in accordance with claim 9, comprising:

first, second and third terminals disposed on said substrate;

said first and second terminals providing power to said temperature sensor and said third terminal providing a temperature indicating output.

17. A temperature sensor in accordance with claim 9, wherein:

one or more of said plurality of resistors of said offset block comprises a pinched well configuration formed in said substrate.

18. A temperature sensor in accordance with claim 16, wherein:

said pinched well configuration comprises a well;

said well comprising a first polarity material formed in said substrate;

said layer comprising a second polarity material formed on said well;

19. A temperature sensor in accordance with claim 18, comprising:

a current source, said current source comprises one or more second resistors, each said one or more second resistors comprising a pinched well second configuration resistor formed in said substrate.

20. A temperature sensor in accordance with claim 19, wherein:

said pinched well second configuration comprises a well and a layer formed on said well;

said well comprising a first polarity material formed in said substrate;

said layer comprising a second polarity material formed on said well;

said layer being in electrical cascade connection with said well.

21. A temperature sensor, comprising:

a silicon substrate, said silicon substrate having formed thereon a bandgap, an offset circuit for providing calibration offsets; and

a gain block;

said bandgap block providing an electrical output that substantially linearly changes with changes in temperature of said substrate;

said offset block comprising a plurality of resistors formed in said silicon substrate, and a programmable link structure configurable to provide a predetermined offset such that said temperature sensor is permanently calibrated.