Browse Prior Art Database

Optimized Performance Feedback

IP.com Disclosure Number: IPCOM000117762D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 101K

Publishing Venue

IBM

Related People

Matsushima, S: AUTHOR [+4]

Abstract

Disclosed is a hardware implementation and control method for acquiring the maximum performance for the overheat-protection function of a Large Scale Integrated circuit (LSI) device by controlling the clock or operation speed thereof. The subject invention is applicable especially to a Micro Processing Unit (MPU) that is used in a Personal Computer (PC) or Workstation for the purpose of power saving during the overheat condition.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Optimized Performance Feedback

      Disclosed is a hardware implementation and control method for
acquiring the maximum performance for the overheat-protection
function of a Large Scale Integrated circuit (LSI) device by
controlling the clock or operation speed thereof.  The subject
invention is applicable especially to a Micro Processing Unit (MPU)
that is used in a Personal Computer (PC) or Workstation for the
purpose of power saving during the overheat condition.

Fig. 1 shows the hardware implementation for the subject invention:
  1.  A register to set the value of the MPU speed.  Speed control
       can be done from 1 to 1/(2n) by the pitch of 1/(2n) by n-bit
       register.
  2.  An external interface for controlling the value of this
register
       (Direction and Clock).  Control can be done independently from
       the system software.
  3.  A Logic circuit for controlling the speed according to the
value
       of register (1).  The logic circuit (3) controls the clock
       itself, or a special signal for speed controller (4).  It
depends
       on the functions of the MPU or the LSI devices.  (For example,
a
       STPCLK# signal of the Intel MPU can be used for this purpose.)

      The following control can be done by using the above hardware.
Monitor the MPU/LSI device (5) temperature by a sensor (6), and
define a threshold under the maximum operational temperature.  Then
give a negative feedback to the MPU speed so that MPU temperature is
go below the threshold.  A feedback control logic circuit (7)
controls the register value so that increment when temperature is
under the threshold, and decrement when temperature is over the
threshold with a constant period.  The feedback control logic circuit
(7) may be simply a comparator logic circuit, or a microcontroller
which monitors the sensor output and control the register.  The MPU
temperature is reduced as much as required when heat generation
becomes higher, and returns to the normal speed when a large heat
generation is over.

Fig. 2 shows how MPU temperature is controlled:
  1.  The MPU speed is given a negative feedback so that the MPU
       temperature is go closer to the threshold.
  2.  The MPU temperature is under the threshold so that the MPU
speed
       becomes maximum.
  3.  The MPU starts a large load operation.  The MPU's heat
generation
       becomes l...