Output Weighting Matrix; Proportional-Integral-Derivative (Pid); Figure 7-1. Intel ® Qst Overview - Intel E6700 - Core 2 Duo Dual-Core Processor Design Manual

®
Figure 7-1. Intel
Temperature sensing
7.1.1

Output Weighting Matrix

Intel QST provides an Output Weighting Matrix that provides a means for a single
thermal sensor to affect the speed of multiple fans. An example of how the matrix
could be used is if a sensor located next to the memory is sensitive to changes in both
the processor heatsink fan and a 2
matrix additional, the Intel QST could command the processor thermal solution fan
and this 2
small changes can result in a smaller change in acoustics than having a single fan
respond to this sensor.
7.1.2

Proportional-Integral-Derivative (PID)

The use of Proportional-Integral-Derivative (PID) control algorithms allow the
magnitude of fan response to be determined based upon the difference between
current temperature readings and specific temperature targets. A major advantage of
a PID Algorithm is the ability to control the fans to achieve sensor temperatures much
closer to the T
Figure 7-2 is an illustration of the PID fan control algorithm. As illustrated in the
figure, when the actual temperature is below the target temperature, the fan will slow
down. The current FSC devices have a fixed temperature versus PWM output
relationship and miss this opportunity to achieve additional acoustic benefits. As the
actual temperature starts ramping up and approaches the target temperature, the
algorithm will instruct the fan to speed up gradually, but will not abruptly increase the
fan speed to respond to the condition. It can allow an overshoot over the target
temperature for a short period of time while ramping up the fan to bring the actual
64
QST Overview
and response
Calculations
(PID)
PECI / SST
Temperature
Sensors
nd
fan to both accelerate a small amount. At the system level these two
.
CONTROL
Intel® Quiet System Technology (Intel® QST)
®
Intel QST
Fan to sensor
Relationship
(Output Weighting Matrix)
System Response
nd
fan in the system. By placing a factor in this
Thermal and Mechanical Design Guidelines
Fan Commands
(PID)
PWM
Fans