Sensor Based Thermal Specification Design Guidance
8.3.2Thermal Design and Modelling
Based on the boundary conditions, the designer can now make the design selection of the thermal solution components. The major components that can be mixed are the fan, fin geometry, heat pipe or air duct design. There are cost and acoustic
To aide in the design process Intel provides TTV thermal models. Please consult your Intel Field Sales Engineer for these tools.
8.3.3Thermal Solution Validation
8.3.3.1Test for Compliance to the TTV Thermal Profile
This step is the same as previously suggested for prior products. The thermal solution is mounted on a test fixture with the TTV and tested at the following conditions:
•TTV is powered to the TDP condition
•Maximum airflow through heatsink
•TAMBIENT at the boundary condition from Section 8.3.1
The following data is collected: TTV power, TTV TCASE and TAMBIENT. and used to calculate ΨCA which is defined as:
ΨCA = (TTV TCASE - TAMBIENT) / Power
This testing is best conducted on a bench to eliminate as many variables as possible when assessing the thermal solution performance. The boundary condition analysis as described in Section 8.3.1 should help in making the bench test simpler to perform.
8.3.3.2Thermal Solution Characterization for Fan Speed Control
The final step in thermal solution validation is to establish the thermal solution
performance,ΨCA and acoustics as a function of fan speed. This data is necessary to allow the fan speed control algorithm developer to program the device. It also is needed to asses the expected acoustic impact of the processor thermal solution in the system.
The fan speed control device may modulate the thermal solution fan speed (RPM) by one of two methods. The first and preferred is pulse width modulation (PWM) signal compliant to the
The alternative is varying the input voltage to the fan. As a result the characterization data needs to also correlate the RPM to PWM or voltage to the thermal solution fan. The fan speed algorithm developer needs to associate the output command from the fan speed control device with the required thermal solution performance. Regardless of which control method is used, the term RPM will be used to indicate required fan speed in the rest of this document.
8.4Fan Speed Control (FSC) Design Process
The next step is to incorporate the thermal solution characterization data into the algorithms for the device controlling the fans.
As a reminder the requirements are:
Thermal/Mechanical Specifications and Design Guidelines | 69 |