EMC6D103-CK SMSC [SMSC Corporation], EMC6D103-CK Datasheet - Page 36

• Manufacturer Part Number: EMC6D103-CK
• Description: FAN CONTROL DEVICE WITH HIGH FREQUENCY PWM
• Manufacturer: SMSC [SMSC Corporation]

Revision 0.4 (04-04-05)
Override all PWM
duty cycle except if
outputs to 100%
disabled or in
manual mode
*See
When in Auto Fan Control Operating Mode the hardware controls the fans directly based on monitoring
of temperature and speed.
To control the fans:
Set the minimum temperature that will turn the fans on. This value is programmed in Registers 67h-
69h: Zone x Low Temp Limit (Auto Fan Mode Only).
The speed of the fan is controlled by the duty cycle set for that device. The duty cycle for the minimum
fan speed must be programmed in Registers 64h-66h: PWMx Minimum Duty Cycle. This value
corresponds to the speed of the fan when the temperature reading is equal to the minimum
temperature LIMIT setting. As the actual temperature increases and is above the Zone LIMIT
temperature and below the Absolute Temperature Limit, the PWM will be determined by a linear
function based on the Auto Fan Speed Range bits in Registers 5Fh-61h.
Time Elapsed?
Spin Up
(5C-5E)
No
Registers 5C-5Eh: PWM Configuration on page 65
Set Fan Output to
Beg in Fan Spin-Up
100%
Figure 7.1 Automatic Fan Control Flow Diagram
Yes
Yes
Yes
End Fan Spin Up
Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
Yes
Set fan speed based on
Temp >= Limit
Auto Fan Rang e
Alg orithm*
Fan Output
(66~68)
Temp >=
AbsLimit
At 0%?
(69~6B)
Yes
No
No
Fan Spinning Up?
End Polling Cycle
DATASHEET
No
Beg in Polling
Cycle
36
No
Auto Fan Mode
Off/Min set to 1?
Set fan to min
Initiated
PWM
(62)
Yes
for details.
No
Set Fan Output to
Hyst Temp
Fan Output
Temp >=
(6C~6D)
At 0%?
0%
No
Yes
SMSC EMC6D103
minimum speed.
Set fan output to
auto fan mode
(63~65)
No
Datasheet
Yes