W83783S_07 WINBOND [Winbond], W83783S_07 Datasheet - Page 19

• Manufacturer Part Number: W83783S_07
• Description: Winbond H/W Monitoring IC
• Manufacturer: WINBOND [Winbond]

6.4.2 Fan speed control
W83783S provides four sets for fan PWM speed control. The duty cycle of PWM can be programmed
by a 8-bit registers which are defined in the Bank0 CR5A and CR5B. The default duty cycle is set to
100%, that is, the default 8-bit registers is set to FFh. The expression of duty can be represented as
follows.
The PWM clock frequency also can be program and defined in the Bank0 CR5C. The application
circuit is shown as follows.
Connector
Connector
Figure 13-1. Fan with Tach Pull-Up to +5V
Figure 13-3. Fan with Tach Pull-Up to +12V
FAN
FAN
FAN Out
FAN Out
and Zener Clamp
+12V
+12V
GND
+12V
GND
+12V
diode
Duty
diode
−
3.9V Zener
cycle
Fan Input
Fan Input
+5V
Pull-up resister
Pull-up resister
4.7K Ohms
(%)
> 1K
Pin 18/19/20
Pin 18/19/20
W83783S
W83783S
=
Programmed 8 - bit Register Value
- 15 -
Connector
Connector
FAN
Figure 13-2. Fan with Tach Pull-Up to +12V, or Totem-Pole
Figure 13-4. Fan with Tach Pull-Up to +12V, or
FAN
255
FAN Out
FAN Out
+12V
GND
+12V
GND
Totem-Pole Putput and Zener Clamp
+12V
+12V
Publication Release Date: August 21, 2007
Output and Register Attenuator
diode
diode
3.9V Zener
×
> 1K
Pull-up resister
4.7K Ohms
14K~39K
100%
Pull-up resister < 1K
or totem-pole output
Fan Input
Fan Input
10K
W83783S
Revision 1.0
Pin 18/19/20
Pin 18/19/20
W83783S
W83783S