emc2106 Standard Microsystems Corp., emc2106 Datasheet - Page 30

• Manufacturer Part Number: emc2106
• Description: Emc2106 Dual Rpm-based Linear Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

APPLICATION NOTE: If the FSC Algorithm is active, then it will generate errant SPIN_FAIL interrupts during the 8
Revision 1.74 (05-08-08)
5.4
5.5
5.6
If the fan driver current detects a short-circuit condition for longer than 2 seconds, then the I_SHORT
status bit is set and an interrupt generated. Additionally, the High Side Fan Driver will be disabled for
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 EMC2106 contains an internal linear DAC for use as a fan driver. This DAC output voltage has
8-bit resolution from 0V to 3.3V. The linear DAC fan driver is also capable of sourcing and sinking up
to 1 mA of current.
The Linear DAC Fan Driver is biased from the VDD_5V supply and this voltage must be present for
the DAC driver to operate properly.
The EMC2106 supports up to four (4) PWM output drivers. Each output driver can be configured to
operate as an open-drain (default) or push-pull driver and each driver can be configured with normal
or inverse polarity. Additionally, the PWM frequencies for PWM1, PWM2, and the two optional PWM
drivers PWM3 and PWM4 are independently programmable with ranges from 9.5Hz to 26kHz in four
programmable frequency bands.
The EMC2106 uses a look-up table to apply a user-programmable fan control profile based on
measured temperature to each 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
Linear DAC Fan Driver
PWM Fan Driver
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
Dual RPM-Based Linear Fan Controller with Hardware Thermal Shutdown
30
5.7), then the user must program an RPM target for each
Appendix
B), the fan output will be automatically
SMSC EMC2106
Datasheet