APPARATUS AND METHOD FOR REDUCING POWER CONSUMPTION BY AN INTEGRATED CIRCUIT

• US 20090289615A1
• Filed: 05/20/2008
• Published: 11/26/2009
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: Advanced Micro Devices, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Foley, Denis
• Granted Patent: US 8,051,312 B2
• Time in Patent Office: Days
• US Class Current: 323/318
• 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 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An integrated circuit includes an energy controller that generates a power supply voltage level for the integrated circuit based on a desired target frequency value for the integrated circuit. The energy controller configures a programmable hardware process sensor based on the power supply voltage level such that the programmable hardware process sensor is capable of mimicking the electrical characteristics of a predetermined critical path associated with the integrated circuit when operating at the power supply voltage level. By monitoring the frequency of the programmable hardware process sensor over a period of time, the energy controller can compare the monitored frequency to an expected value and determine whether the power supply voltage level can be adjusted or whether it should be maintained.

Claims

1. An integrated circuit for use in determining a power supply voltage level for the integrated circuit, comprising:

an energy controller operably coupled to a programmable hardware sensor, wherein the energy controller is operative to configure the programmable hardware process sensor based on a power supply voltage level,

wherein the programmable hardware process sensor is operative to generate a sensor count value that represents a frequency of operation of the configured, programmable hardware process sensor after having been driven at the power supply voltage level for a predetermined period of time, and

wherein the energy controller is operative to compare the sensor count value with an expected count value to determine whether the power supply voltage level can be adjusted to alter power consumption by the integrated circuit.

2. The integrated circuit of claim 1, further comprising one or more functional logic blocks capable of performing operations on data, wherein the one or more functional blocks are operative to set a target frequency value of operation for the integrated circuit based on the requirements of a particular operation to be performed by the one or more functional blocks.

3. The integrated circuit of claim 2, wherein the energy controller is further operative to determine the expected count value based on the target frequency value.

4. The integrated circuit of claim 2, further comprising memory operably coupled to the energy controller and operative to store a plurality of expected count values, wherein each expected count value is associated with a corresponding particular target frequency value, and wherein each association was previously determined based on empirical analysis of the programmable hardware process sensor and the one or more functional logic blocks over a spectrum of operating conditions.

5. The integrated circuit of claim 1, wherein the energy controller is further operative to request a power supply voltage at the power supply voltage level from a power regulator operably coupled to the integrated circuit, and is further operative to provide the received power supply voltage to the integrated circuit.

6. The integrated circuit of claim 1, wherein:

the energy controller is further operative to determine the power supply voltage level,

the power supply voltage level is initially determined to be a predetermined voltage level to ensure proper operation of the integrated circuit; and

thereafter, the power supply voltage level is determined based on the results of the comparison of the sensor count value and the expected count value.

7. The integrated circuit of claim 1, the energy controller is further operative to configure the programmable hardware process sensor such that the configured, programmable hardware process sensor mimics the electrical characteristics of a predetermined critical path associated with the integrated circuit when operating at the power supply voltage level.

8. The integrated circuit of claim 7, wherein the programmable hardware process sensor comprises:

a programmable ring oscillator comprising a predetermined number of paths, wherein each path comprises a predetermined number of path sections, wherein each path section is associated with a particular path is capable of mimicking a corresponding predetermined electrical characteristic of a critical path associated with the integrated circuit, wherein the energy controller is operative to configure the programmable hardware process sensor by configuring the programmable ring oscillator such that the programmed ring oscillator mimics the electrical characteristics of the predetermined critical path associated with the integrated circuit when operating at the power supply voltage level.

9. The integrated circuit of claim 8, wherein each of the predetermined electrical characteristics account for critical path behavior associated with at least one of:

transistor process;

relative performance of different threshold devices;

metal layers of the integrated circuit;

p-dominated and n-dominated circuits in a CMOS device; and

paths that are wire dominated.

10. The integrated circuit of claim 8, wherein the programmable hardware process sensor further comprises a counter that is operative to count the frequency of operation of the programmable ring oscillator.

11. The integrated circuit of claim 1, wherein:

the energy controller is operative to adjust the power supply voltage level by lowering the power supply voltage level by a predetermined amount when the sensor count value is greater than one of;

the expected count value, and

the expected count value plus a predetermined threshold amount; and

the energy controller is operative to maintain the power supply voltage level when the sensor count value is equal to one of;

the expected count value; and

the expected count value plus a predetermined threshold amount.

12. A method for determining a power supply voltage level for an integrated circuit, comprising:

configuring a programmable hardware process sensor located on the integrated circuit based on a power supply voltage level; and

comparing a sensor count value of the configured programmable hardware process sensor with an expected count value to determine whether the power supply voltage level can be adjusted to alter power consumption by the integrated circuit, wherein the sensor count value represents a frequency of operation of the configured, programmable hardware process sensor after having been driven at the power supply voltage level for a predetermined period of time.

13. The method of claim 12, further comprising:

associating a plurality of expected count values with a plurality of target frequency values based on empirical analysis of the programmable hardware process sensor and the one or more functional logic blocks of the integrated circuit over a spectrum of operating conditions; and

determining the expected count value based on a target frequency value of operation for the integrated circuit.

14. The method of claim 12, further comprising setting a target frequency value of operation for the integrated circuit based on the requirements of a particular operation to be performed by the one or more functional blocks.

15. The method of claim 12, determining the power supply voltage level such that the power supply voltage level is one of:

determined to be a predetermined voltage level to ensure proper operation of the integrated circuit; and

based on the results of the comparison of the sensor count value with the expected count value.

16. The method of claim 12, further comprising requesting a power supply voltage at the power supply voltage level.

17. The method of claim 12, wherein the configured, programmable hardware process sensor is configured to mimic the electrical characteristics of a predetermined critical path associated with the integrated circuit when operating at the power supply voltage level.

18. The method of claim 17, wherein each of the predetermined electrical characteristics account for critical path behavior associated with at least one of:

transistor process;

relative performance of different threshold devices;

metal layers of the integrated circuit;

p-dominated and n-dominated circuits in a CMOS device; and

paths that are wire dominated.

19. The method of claim 12, further comprising:

lowering the power supply voltage level by a predetermined amount when the sensor count value is greater than one of;

the expected count value, and

the expected count value plus a predetermined threshold amount;

maintaining the power supply voltage level when the sensor count value is equal to one of;

the expected count value; and

the expected count value plus a predetermined threshold amount.

20. An integrated circuit for use in determining a power supply voltage level for the integrated circuit, comprising:

an expected count determinator operative to determine an expected count value of a configured programmable oscillator for a target frequency value of operation for the integrated circuit;

a voltage determinator operative to determine a power supply voltage level and to provide a power supply voltage set at the determined power supply voltage level to the integrated circuit;

a programmable ring oscillator controller operative to generate a programmable ring oscillator control signal based on the determined power supply voltage and to configure a programmable ring oscillator based on the programmable ring oscillator control signal, a comparator operative to read a sensor count value at the conclusion of a predetermined period of time and to compare the sensor count value with the expected count value, wherein the sensor count value represents the frequency of operation of the configured, programmable ring oscillator, and

wherein the voltage determinator is operative to adjust or maintain the power supply voltage level based on the comparison of the sensor count value with the expected count value.

21. A method for determining a power supply voltage level for an integrated circuit, comprising:

determining an expected count value of a configured programmable ring oscillator for the target frequency value;

determining a power supply voltage level;

configuring a programmable ring oscillator of the programmable hardware process sensor based on the determined power supply voltage level;

providing a power supply voltage set at the determined power supply voltage level to the integrated circuit;

reading a sensor count value at the conclusion of a predetermined period of time, wherein the sensor count value represents the frequency of operation of the configured, programmable ring oscillator;

comparing the sensor count value with the expected count value;

adjusting or maintaining the power supply voltage level based on the comparison of the sensor count value with the expected count value.

22. The method of claim 21, wherein the power supply voltage level is initially determined to be a predetermined voltage level to ensure proper operation of the integrated circuit for operation at least substantially at a target frequency value of operation of the integrated circuit.

23. The method of claim 21, wherein configuring a programmable ring oscillator of the programmable hardware process sensor based on the determined power supply voltage level comprises determining a programmable ring oscillator control signal based on the determined power supply voltage level.

24. The method of claim 21, wherein reading a sensor count value at the conclusion of a predetermined period of time, comprises:

waiting a first predetermined period of time following the configuration of the programmable ring oscillator to allow the programmable ring oscillator to stabilize;

resetting a counter associated with the programmable ring oscillator;

running the counter for another predetermined period of time and reading the sensor at the conclusion of the another predetermined period of time, thereby yielding the sensor count value.

25. A device comprising:

an integrated circuit for use in determining a power supply voltage level for the integrated circuit, wherein the integrated circuit comprises;

an energy controller operably coupled to a programmable hardware sensor, wherein the energy controller is operative to configure the programmable hardware process sensor based on a power supply voltage level,

wherein the programmable hardware process sensor is operative to generate a sensor count value that represents a frequency of operation of the configured, programmable hardware process sensor after having been driven at the power supply voltage level for a predetermined period of time, and

wherein the energy controller is operative to compare the sensor count value with an expected count value to determine whether the power supply voltage level can be adjusted to reduce power consumption by the integrated circuit.

26. Memory storing executable instructions and capable of being executed by one or more processors such that when executed by the one or more processors the executable instructions are capable of designing logic that, when manufactured, is configured to:

configure a programmable hardware process sensor located on the integrated circuit based on a power supply voltage level; and

compare a sensor count value of the configured programmable hardware process sensor with an expected count value to determine whether the power supply voltage level can be adjusted to alter power consumption by the integrated circuit, wherein the sensor count value represents a frequency of operation of the configured, programmable hardware process sensor after having been driven at the power supply voltage level for a predetermined period of time.

27. The memory of claim 26 wherein the stored executable instructions comprise hardware description language instructions.