Intel Pentium D 945 HH80553PG0964MN Manuel D’Utilisation
Codes de produits
HH80553PG0964MN
Datasheet
87
Thermal Specifications and Design Considerations
As a bi-directional signal, PROCHOT# allows for some protection of various components
from over-temperature situations. The PROCHOT# signal is bi-directional in that it can
either signal when the processor (either core) has reached its maximum operating
temperature or be driven from an external source to activate the TCC. The ability to
activate the TCC via PROCHOT# can provide a means for thermal protection of system
components.
Bi-directional PROCHOT# (if enabled) can allow VR thermal designs to target maximum
sustained current instead of maximum current. Systems should still provide proper
cooling for the VR, and rely on bi-directional PROCHOT# only as a backup in case of
system cooling failure. The system thermal design should allow the power delivery
circuitry to operate within its temperature specification even while the processor is
operating at its Thermal Design Power. With a properly designed and characterized
thermal solution, it is anticipated that bi-directional PROCHOT# would only be asserted
for very short periods of time when running the most power intensive applications. An
under-designed thermal solution that is not able to prevent excessive assertion of
PROCHOT# in the anticipated ambient environment may cause a noticeable
performance loss. Refer to the Voltage Regulator-Down (VRD) 10.1 Design Guide for
Desktop Socket 775 for details on implementing the bi-directional PROCHOT# feature.
5.2.4
FORCEPR# Signal
The FORCEPR# (force power reduction) input can be used by the platform to cause the
processor (both cores) to activate the TCC. If the Thermal Monitor is enabled, the TCC
will be activated upon the assertion of the FORCEPR# signal. The TCC will remain active
until the system deasserts FORCEPR#. FORCEPR# is an asynchronous input.
FORCEPR# can be used to thermally protect other system components. To use the VR
as an example, when the FORCEPR# pin is asserted, the TCC circuit in the processor
(both cores) will activate, reducing the current consumption of the processor and the
corresponding temperature of the VR.
Note that assertion of the FORCEPR# does not automatically assert PROCHOT#. As
mentioned previously, the PROCHOT# signal is asserted when a high temperature
situation is detected. A minimum pulse width of 500 µs is recommend when the
FORCEPR# is asserted by the system. Sustained activation of the FORCEPR# pin may
cause noticeable platform performance degradation.
One application is the thermal protection of voltage regulators (VR). System designers
can create a circuit to monitor the VR temperature and activate the TCC when the
temperature limit of the VR is reached. By asserting FORCEPR# (pulled-low) and
activating the TCC, the VR can cool down as a result of reduced processor power
consumption. FORCEPR# can allow VR thermal designs to target maximum sustained
current instead of maximum current. Systems should still provide proper cooling for the
VR, and rely on FORCEPR# only as a backup in case of system cooling failure. The
system thermal design should allow the power delivery circuitry to operate within its
temperature specification even while the processor is operating at its Thermal Design
Power. With a properly designed and characterized thermal solution, it is anticipated
that FORCEPR# would only be asserted for very short periods of time when running the
most power intensive applications. An under-designed thermal solution that is not able
to prevent excessive assertion of FORCEPR# in the anticipated ambient environment
may cause a noticeable performance loss. Refer to the Voltage Regulator-Down (VRD)
10.1 Design Guide for Desktop Socket 775 for details on implementing the FORCEPR#
feature.