Intel EM64T - Celeron D 336 Boxed Ena User Manual

Acoustic Fan Speed Control
R
54 Thermal/Mechanical Design Guide
Chapter
5 discussed in detail the reference thermal solution, including the target Ψ
CA
, fan speed
and temperatures to ensure that T
C-MAX
is not exceeded for TDP power at a given ambient
temperature. The resulting variable speed fan (VSF) curve is the upper limit on fan speed.
The benefit of this upper limit will become more apparent when the fan speed controller is
responding to the on-die thermal diode temperatures.
Figure 16. Thermistor Set Points
Fan Speed
(RPM)
Fan Inlet
Temperature (°C)
Full
Speed
30
38
Min.
Operating
Variable Speed Fan (VSF) Curve
Fan Speed
(RPM)
Fan Inlet
Temperature (°C)
Full
Speed
30
38
Min.
Operating
Variable Speed Fan (VSF) Curve
6.2.3 Minimum Fan Speed Set Point
The final aspect of thermal solution design is to determine the minimum speed at which the fan
will be allowed to operate. This value can be driven by the cooling requirements for another
portion of the design, such as the processor voltage regulator, or by functional limits of the fan
design.
Per the Fan Specification for 4 wire PWM Controlled Fans, there are three possible options to
consider:
• Type A: The fan will run at minimum RPM for all PWM duty cycle values less than
minimum duty cycle. This would be programmed into the fan controller located on the fan
hub. It can not be overridden by the external fan speed control.
• Type B: The fan will run at minimum RPM for all non-zero PWM duty cycle values less than
minimum duty cycle and the fan will turn off at 0% PWM duty cycle.
• Type C: The fan will stop running when the current provided to the motor windings is
insufficient to support commutation. The fan would turn off at 0% PWM duty cycle input.
For the reference thermal solution, Type A was implemented.

Intel EM64T - Celeron D 336 Boxed Ena Specifications

General

Brand	Intel
Model	EM64T - Celeron D 336 Boxed Ena
Category	Computer Hardware
Language	English