RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
5.7.3
Internal HW_SHDN Signal
The HW_SHDN output from the Critical/Thermal Shutdown Monitor is a logical indicator of the
temperature state of the chosen external diode channel. HW_SHDN is an internal signal routed as an
input to the Thermal / Critical Shutdown logic.
The HW_SHDN output is set to logic ‘1’ when the indicated temperature exceeds the temperature
threshold (TP) established by the TRIP_SET input pin (as shown in Figure 5.5) for a number of
consecutive measurements defined by the fault queue. If the HW_SHDN output is asserted and the
temperature drops below TP, then it will be set to a logic ‘0’ state.
Temperature drops
to TP or below
Temperature
Exceeds TP
Measurements End
TP
Temperature
HW_SHDN
not defined
th
After 4 measurement,
HW_SHDN set
Figure 5.5 HW_SHDN Operation
SMSC EMC2102
Revision 1.95 (10-19-06)
DATA2S9HEET
SMSC [ SMSC CORPORATION ]
