RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
The EMC2102’s RPM based Fan Control Algorithm has programmable configuration settings for
parameters such as ramp-rate control and spin up conditions. The fan driver automatically detects and
attempts to alleviate a stalled/stuck fan condition while also asserting the ALERT# pin. The EMC2102
works with fans that operate up to 16,000 RPMs and provide a valid tachometer signal. The fan
controller will function either with an externally supplied 32.768KHz clock source or with it’s own
internal 32.768KHz oscillator depending on the required accuracy.
Set TACH Target
Count
Measure Fan Speed
Spin Up
Required
?
Yes
Perform Spin Up
Routine
No
TACH
Reading =
TACH
Yes
Maintain Fan Drive
Target?
No
TACH
Reading <
TACH
Ramp Rate Control
No
Yes
Target?
Reduce Fan Drive
Increase Fan Drive
Figure 5.2 RPM based Fan Control Algorithm
Revision 1.95 (10-19-06)
SMSC EMC2102
DATA2S2HEET
SMSC [ SMSC CORPORATION ]
