emc2105 Standard Microsystems Corp., emc2105 Datasheet - Page 27

• Manufacturer Part Number: emc2105
• Description: Emc2105 Rpm-based High Side Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

RPM-Based High Side Fan Controller with Hardware Thermal Shutdown
Datasheet
APPLICATION NOTE: If the FSC Algorithm is active, then it will generate errant SPIN_FAIL interrupts during the 8
SMSC EMC2105
5.4
8 seconds. After this 8 second time has elapsed, it will be allowed to restart invoking the Spin Up
Routine before returning to its previous drive setting.
The EMC2105 uses a look-up table to apply a user-programmable fan control profile based on
measured temperature to the fan driver. In this look-up table, each temperature channel is allowed to
control the fan drive output independently (or jointly) by programming up to eight pairs of temperature
and drive setting entries.
The user programs the look-up table based on the desired operation. If the RPM based Fan Speed
Control Algorithm is to be used (see
temperature setting of interest. Alternately, if the RPM based Fan Speed Control Algorithm is not to be
used, then the user must program a drive setting for each temperature setting of interest.
If the measured temperature on the External Diode channel meets or exceeds any of the temperature
thresholds for any of the temperature columns (see
set to the desired setting corresponding to the exceeded temperature. In cases where multiple
temperature channel thresholds are exceeded, the highest fan drive setting will take precedence.
When the measured temperature drops to a point below a lower threshold minus the hysteresis value,
the fan output will be set to the corresponding lower set point.
Figure 5.3
channel.
See
Fan Control Look-Up Table
Appendix B
second time that the fan driver is held off.
shows an example of this operation using temperature - drive setting pairs for a single
for examples of the Look Up Table operation.
DATASHEET
Section
27
5.5), then the user must program an RPM target for each
Appendix
B), the fan output will be automatically
Revision 1.74 (05-08-08)