Sensor Based Thermal Specification Design Guidance
8Sensor Based Thermal Specification Design Guidance
The sensor based thermal specification presents opportunities for the system designer to optimize the acoustics and simplify thermal validation. The sensor based specification utilizes the Digital Thermal Sensor information accessed via the PECI interface.
This chapter will review thermal solution design options, fan speed control design guidance & implementation options and suggestions on validation both with the TTV and the live die in a shipping system.
Note: A new fan speed control implementation scheme is called DTS 1.1 introduced in Section 8.4.1.
8.1Sensor Based Specification Overview (DTS 1.0)
Create a thermal specification that meets the following requirements:
•Use Digital Thermal Sensor (DTS) for
•Single point of reference for thermal specification compliance over all operating conditions.
•Does not required measuring processor power and case temperature during functional system thermal validation.
•Opportunity for acoustic benefits for DTS values between TCONTROL and
Thermal specifications based on the processor case temperature have some notable gaps to optimal acoustic design. When the ambient temperature is less than the maximum design point, the fan speed control system (FSC) will over cool the processor. The FSC has no feedback mechanism to detect this over cooling, this is shown in the top half of Figure
The sensor based specification will allow the FSC to be operated at the maximum allowable silicon temperature or TJ for the measured ambient. This will provide optimal acoustics for operation above TCONTROL. See lower half of Figure
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