Dynamic voltage reference for sampling delta based temperature sensor

• US 9,347,836 B2
• Filed: 11/15/2011
• Issued: 05/24/2016
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: ATI Technologies ULC (Advanced Micro Devices, Inc.)
• Original Assignee: ATI Technologies ULC (Advanced Micro Devices, Inc.)
• Inventors: Temkine, Grigori, Chekmazov, Filipp, Edelshteyn, Paul, Drapkin, Oleg, Au, Kristina
• Primary Examiner(s): Verbitsky, Gail Kaplan
• Application Number:
  US13/296,804
• Publication Number:
  US 20130120930A1
• Time in Patent Office: 1,652 Days
• Field of Search: 374170-173, 374/178, 374/183, 374/185, 374/4, 374/5, 374/141, 374/1, 702/130, 702/99, 327/512, 327/513
• US Class Current: 1/1
• 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

Abstract

A system and method for measuring integrated circuit (IC) temperature. An integrated circuit (IC) includes a thermal sensor and data processing circuitry. The thermal sensor utilizes switched currents provided to a reference diode and a thermal diode. The ratios of the currents provided to each of these diodes may be chosen to provide a given delta value between the resulting sampled diode voltages. At a later time, a different ratio of currents may be provided to each of these diodes to provide a second given delta value between the resulting sampled diode voltages. A differential amplifier within the data processing circuitry may receive the analog sampled voltages and determine the delta values. Other components within the data processing circuitry may at least digitize and store one or both of the delta values. A difference between the digitized delta values may calculated and used to determine an IC temperature digitized code.

Claims

1. A temperature measurement circuit comprising:

circuitry configured to;

generate a temperature dependent first reference voltage, responsive to a reference current flowing through a reference diode at a first point-in-time;

generate a temperature dependent second reference voltage, responsive to a reference current flowing through the reference diode at a second point-in-time after the first point-in-time;

generate a temperature dependent first thermal voltage, responsive to a first thermal current flowing through a thermal diode at the first point-in-time;

generate a temperature dependent second thermal voltage, responsive to a second thermal current flowing through the thermal diode at the second point-in-time, wherein the second thermal current is different from the first thermal current;

determine a first difference between the first thermal voltage and the first reference voltage at the first point-in-time using a differential amplifier;

determine a second difference between the second thermal voltage and the second reference voltage at the second point-in-time using the differential amplifier;

determine an indication of a temperature based at least in part on the first difference and the second difference; and

output the indication of the temperature.

2. The temperature measurement circuit as recited in claim 1, wherein the circuitry is further configured to:

generate the first thermal voltage and the first reference voltage at a given area of an integrated circuit at the first point-in-time; and

generate the second thermal voltage and the second reference voltage at the given area at the second point-in-time, wherein any difference between the first reference voltage and the second reference voltage at the given area is based on a temperature difference that occurs between the first point-in-time and the second point-in-time.

3. The temperature measurement circuit as recited in claim 2, wherein the circuitry is further configured to:

digitize using an analog-to-digital converter within a digital digitizer each of the first difference and the second difference; and

determine using a comparator a third difference between the digitized first difference and the digitized second difference.

4. The temperature measurement circuit as recited in claim 3, wherein a reference current density is a ratio of the reference current to a cross-sectional area of the reference diode through which the reference current flows, wherein each of a first and a second thermal current density is a ratio of a respective first or second thermal current to a cross-sectional area of the thermal diode through which the respective first or second thermal current flows at a respective first or second point-in-time, and wherein a first ratio of the reference current density to the first thermal current density provided at the first point-in-time is a square root of a second ratio of the second thermal current density provided at the second point-in-time to the first thermal current density.

5. The temperature measurement circuit as recited in claim 4, wherein a ratio of the reference current density to the second current density provided at the second point-in-time is an inverse of the first ratio.

6. The temperature measurement circuit as recited in claim 4, wherein the reference diode is smaller than the thermal diode.

7. The temperature measurement circuit as recited in claim 3, wherein the circuitry is further configured to:

convert using a temperature data converter the third difference to a temperature digital code; and

use the temperature data converter to send the temperature digital code to the thermal cooling controller configured to select a lower performance-power state.

8. A method comprising:

generating a temperature dependent first reference voltage, responsive to a reference current flowing through a reference diode at a first point-in-time;

generating a temperature dependent second reference voltage, responsive to a reference current flowing through the reference diode at a second point-in-time after the first point-in-time;

generating a temperature dependent first thermal voltage, responsive to a first thermal current flowing through a thermal diode at the first point-in-time;

generating a temperature dependent second thermal voltage, responsive to a second thermal current flowing through the thermal diode at the second point-in-time, wherein the second thermal current is different from the first thermal current;

determining a first difference between the first thermal voltage and the first reference voltage at the first point-in-time using a differential amplifier;

determining a second difference between the second thermal voltage and the second reference voltage at the second point-in-time using the differential amplifier;

determining an indication of a temperature based at least in part on the first difference and the second difference; and

outputting the indication of the temperature.

9. The method as recited in claim 8, further comprising:

generating the first thermal voltage and the first reference voltage at a given area of an integrated circuit at the first point-in-time; and

generating the second thermal voltage and the second reference voltage at the given area at the second point-in-time, wherein any difference between the first reference voltage and the second reference voltage at the given area is based on a temperature difference that occurs between the first point-in-time and the second point-in-time.

10. The method as recited in claim 9, wherein the method further comprises:

digitizing using an analog-to-digital converter within a digital digitizer each of the first difference and the second difference; and

determining using a comparator a third difference between the digitized first difference and the digitized second difference.

11. The method as recited in claim 10, wherein a reference current density is a ratio of the reference current to a cross-sectional area of the reference diode through which the reference current flows, wherein each of a first and a second thermal current density is a ratio of a respective first or second thermal current to a cross-sectional area of the thermal diode through which the respective first or second thermal current flows at a respective first or second point-in-time, and wherein a first ratio of the reference current density to the first thermal current density provided at the first point-in-time is a square root of a second ratio of the second thermal current density provided at the second point-in-time to the first thermal current density.

12. The method as recited in claim 11, wherein a ratio of the reference current density to the second current density provided at the second point-in-time is an inverse of the first ratio.

13. The method as recited in claim 10, wherein the reference diode is smaller than the thermal diode.

14. The method as recited in claim 12, further comprising sending the indication of the temperature to the thermal cooling controller configured to perform at least one of the following:

select a lower performance-power state and increase a speed of a fan.

15. A computer system comprising:

an integrated circuit (IC) comprising a temperature monitor to;

generate a temperature dependent first reference voltage, responsive to a reference current flowing through a reference diode at a first point-in-time;

generate a temperature dependent second reference voltage, responsive to a reference current flowing through the reference diode at a second point-in-time after the first point-in-time;

generate a temperature dependent first thermal voltage, responsive to a first thermal current flowing through a thermal diode at the first point-in-time;

generate a temperature dependent second thermal voltage, responsive to a second thermal current flowing through the thermal diode at the second point-in-time, wherein the second thermal current is different from the first thermal current; and

determine a first difference between the first thermal voltage and the first reference voltage at the first point-in-time using a differential amplifier;

determine a second difference between the second thermal voltage and the second reference voltage at the second point-in-time using the differential amplifier;

determine an indication of a temperature based at least in part on the first difference and the second difference using a temperature data converter; and

a thermal cooling controller to;

receive the indication of the temperature from the temperature data converter; and

change a condition of operation for the IC in response to determining the temperature exceeds a given threshold.

16. The computer system as recited in claim 15, wherein the temperature monitor comprises circuitry to further:

generate the first thermal voltage and the first reference voltage at a given area of an integrated circuit at the first point-in-time; and

generate the second thermal voltage and the second reference voltage at the given area at the second point-in-time, wherein any difference between the first reference voltage and the second reference voltage at the given area is based on a temperature difference that occurs between the first point-in-time and the second point-in-time.

17. The computer system as recited in claim 16, wherein changing the condition of operation by the thermal cooling controller comprises at least one of the following:

selecting a lower performance-power state and increasing a speed of a fan.

18. A temperature monitor comprising:

a reference diode to;

generate a temperature dependent first reference voltage responsive to a reference current flowing through the reference diode at a first point-in-time; and

generate a temperature dependent second reference voltage responsive to the reference current flowing through the reference diode at a second point-in-time after the first point-in-time;

a thermal diode to;

generate a temperature dependent first voltage, responsive to a first current flowing through a thermal diode at the first point-in-time; and

generate a temperature dependent second voltage, responsive to a second current flowing through the thermal diode at the second point-in-time, wherein the second current is different from the first current;

a differential amplifier to;

determine a first difference between the first thermal voltage and the first reference voltage at the first point-in-time; and

determine a second difference between the second thermal voltage and the second reference voltage at the second point-in-time; and

a temperature data converter to output an indication of a temperature, wherein the indication of the temperature is based at least in part on the first difference and the second difference.