Performance-temperature optimization by cooperatively varying the voltage and frequency of a circuit

• US 6,047,248 A
• Filed: 10/19/1998
• Issued: 04/04/2000
• Est. Priority Date: 04/29/1996
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Kirkpatrick, Edward Scott, Larsen, Thor Arne, Georgiou, Christos John
• Primary Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US09/226,097
• Time in Patent Office: 533 Days
• Field of Search: 702/132, 713/320, 713/322, 713/323, 713/324, 713/330, 327/513
• US Class Current: 702/132
• CPC Class Codes: G05D 23/1913 delivering a series of pulses
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor
• 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 1/3296 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

A system and method using thermal feedback to cooperatively vary a voltage and frequency of a circuit to control heating while maintaining synchronization. Preferably, on-chip thermal sensors are used for feedback. A system having features of the invention includes: a thermal sensor coupled to the circuit, the thermal sensor generating a temperature signal which is a function of a temperature associated with the functional unit; a temperature decoder having an input and an output, the input coupled to the thermal sensor for decoding the temperature signal; a comparator having one input coupled to the decoder for comparing a decoded temperature signal with a predetermined temperature threshold signal coupled to a second input, the comparator enabling a voltage/clock control signal as a function of the decoded temperature signal and the predetermined temperature threshold; an adjustable voltage regulator coupled to the voltage/clock control signal; and a clock selector coupled to the voltage/clock control signal; wherein the voltage regulator and the clock selector are adapted to cooperatively vary the voltage and the frequency of the circuit to a predetermined voltage-frequency pair, responsive to the voltage/clock control signal.

Claims

1. A method of using thermal feedback to cooperatively vary a voltage and a frequency applied to a synchronous circuit to control heating while maintaining synchronization, said method comprising the steps of:

characterizing said circuit over a range of voltages and corresponding clock frequencies, and generating one or more voltage-frequency pairs capable of satisfying worst case propagation delays for critical timing paths in said circuit;

generating a temperature signal which is a function of a temperature associated with the circuit;

comparing the temperature signal with a predetermined temperature threshold signal; and

cooperatively varying the voltage and the frequency of the circuit to a predetermined voltage-frequency pair, responsive to said step of comparing, whereby the voltage-frequency pair is selected according to said characterization of said critical timing paths.

2. A method of using thermal feedback to cooperatively vary a voltage and a frequency applied to a synchronous circuit to control heating while maintaining synchronization, wherein the circuit comprises a plurality of functional units for processing data in a data processing system, the method comprising the steps of:

characterizing each said functional unit over a range of voltages and corresponding clock frequencies, and generating one or more voltage-freauency pairs associated with the functional unit capable of satisfying worst case propagation delays for critical timing paths in said circuit;

generating a temperature signal for a functional unit, the temperature signal being a function of a temperature associated with the functional unit;

identifying the functional unit associated with the temperature signal, responsive to said generating step;

comparing the temperature signal with a predetermined temperature threshold signal; and

cooperatively varying the voltage and the frequency of the functional unit to a predetermined voltage-frequency pair, responsive to said step of comparing, whereby the voltage-frequency pair is selected according to said characterization of said critical timing paths.