Intel Solo T1300 BX80538756 ユーザーズマニュアル
製品コード
BX80538756
Datasheet
87
Thermal Specifications and Design Considerations
When calculating a temperature based on thermal diode measurements, a number of
parameters must be either measured or assumed. Most devices measure the diode
ideality and assume a series resistance and ideality trim value, although some are
capable of also measuring the series resistance. Calculating the temperature is then
accomplished using the equations listed under
. In most temperature sensing
devices, an expected value for the diode ideality is designed-in to the temperature
calculation equation. If the designer of the temperature sensing device assumes a
perfect diode the ideality value (also called n
trim
) will be 1.000. Given that most diodes
are not perfect, the designers usually select an n
trim
value that more closely matches
the behavior of the diodes in the processor. If the processors diode ideality deviates
from that of n
trim
, each calculated temperature will be offset by a fixed amount. This
temperature offset can be calculated with the equation:
T
error(nf)
= T
measured
X (1 - n
actual
/n
trim
)
Where T
error(nf)
is the offset in degrees C, T
measured
is in Kelvin, n
actual
is the measured
ideality of the diode, and n
trim
is the diode ideality assumed by the temperature
sensing device.
5.1.2
Thermal Diode Offset
In order to improve the accuracy of diode based temperature measurements, a
temperature offset value (specified as Toffset) will be programmed into a processor
Model Specific Register (MSR) which will contain thermal diode characterization data.
During manufacturing each processors thermal diode will be evaluated for its behavior
relative to a theoretical diode. Using the equation above, the temperature error created
by the difference between n
trim
and the actual ideality of the particular processor will
be calculated.
If the n
If the n
trim
value used to calculate Toffset differs from the n
trim
value used in a
temperature sensing device, the T
error(nf)
may not be accurate. If desired, the Toffset
can be adjusted by calculating n
actual
and then recalculating the offset using the actual
n
trim
as defined in the temperature sensor manufacturers' datasheet.
The n
trim
used to calculate the Diode Correction Toffset are listed in the table below
5.1.3
Intel® Thermal Monitor
The Intel Thermal Monitor helps control the processor temperature by activating the
TCC (Thermal Control Circuit) when the processor silicon reaches its maximum
operating temperature. The temperature at which the Intel Thermal Monitor activates
the TCC is not user configurable. Bus traffic is snooped in the normal manner, and
interrupt requests are latched (and serviced during the time that the clocks are on)
while the TCC is active.
With a properly designed and characterized thermal solution, it is anticipated that the
TCC would only be activated for very short periods of time when running the most
power intensive applications. The processor performance impact due to these brief
periods of TCC activation is expected to be minor and hence not detectable. An under-
designed thermal solution that is not able to prevent excessive activation of the TCC in
the anticipated ambient environment may cause a noticeable performance loss, and
may affect the long-term reliability of the processor. In addition, a thermal solution that
is significantly under designed may not be capable of cooling the processor even when
the TCC is active continuously.
Table 28.
Thermal Diode n
trim
and Diode Correction Toffset
Symbol
Parameter
Value
n
trim
Diode ideality used to calculate Toffset
1.01