In
Figure
75W the fans will be ~ 1600 RPM keeping the Tj at ~ 89C. Blue line represent DTS 1.0
with ambient sensor. The fans with DTS 1.0 will be roughly at the same speed
~ 1650 RPM resulting in Tj at ~ 88 C. The Golden line represents the fan speed control
option where fan ramps to keep the Tj at T
case with overcooling to CPU to Tj of ~ 81 C. Below T
fan speed to minimum or as desired by other system cooling needs.
Figure 8-9.
Fan Response Comparison with Various Fan Speed Control Options
Notes:
1.
Tj is the CPU temperatuers and can be calulated from relative DTS value (PECI) and TjMax register.
Tj = DTS + TjMax(register)
8.5
System Validation
System validation should focus on ensuring the fan speed control algorithm is
responding appropriately to the DTS values and T
well as any other device being monitored for thermal compliance.
Since the processor thermal solution has already been validated using the TTV to the
thermal specifications at the predicted T
chassis is not necessary.
Once the heatsink has been demonstrated to meet the TTV Thermal Profile, it should be
evaluated on a functional system at the boundary conditions.
76
8-9, the red line represents the DTS 1.1 fan speed control implementation. At
Sensor Based Thermal Specification Design Guidance
. Fan will be running full speed in this
CONTROL
, the designer can set the
CONTROL
data in the case of DTS 1.0 as
AMBIENT
, additional TTV based testing in the
AMBIENT
Thermal/Mechanical Specifications and Design Guidelines