EMC2300-AZC-TR SMSC, EMC2300-AZC-TR Datasheet - Page 32

• Manufacturer Part Number: EMC2300-AZC-TR
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC2300-AZC-TR

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 0.32 (06-23-08)
*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 activate the Automatic Fan control algorithm. 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.
Registers 5C-5Eh: PWM Configuration on page 59
duty cycle except if
Override all PWM
outputs to 100%
disabled or in
manual mode
Time Elapsed?
(5C-5E)
Spin Up
No
Figure 7.1 Automatic Fan Control Flow Diagram
Set Fan Output to
Begin Fan Spin-Up
100%
Yes
Yes
Yes
End Fan Spin Up
DATASHEET
Yes
32
Fan Control Device with High Frequency PWM and Temperature Monitors
Set fan speed based on
Fan Spinning Up?
Auto Fan Range
End Polling Cycle
T emp >= Low
Begin Polling
Algorithm*
Min PWM
Temp >=
(67~69)
AbsLimit
(6A~6C)
Yes
at 0%?
Cycle
Limit
No
No
No
for details.
No
Auto Fan Mode
Initiated
Set fan to min
(64~ 66)
PWM
SMSC EMC2300
Datasheet