W83637HF Winbond Electronics Corp America, W83637HF Datasheet - Page 36

• Manufacturer Part Number: W83637HF
• Description: Description = LPC I/o Plus H/w Monitor, Smart Fan Control, Smart Card (PC/SC) Reader, Memory Stick Reader I/F, Sd/mmc Card Reader I/f ;; Package = QFP 128
• Manufacturer: Winbond Electronics Corp America

6.4.2 Fan speed control
The W83637HF provides maximum 3 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 Index 01h, Index 03h and Index 11h.
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 Index 00h, Index 02h and
Index 10h. The application circuit is shown as follows.
Duty cycle
PWM Clock Input
−
(%)
=
G
Programmed 8 - bit Register Value
D
S
R1
NMOS
Figure 6.5
- 31 -
+12V
R2
255
Publication Release Date: June 25, 2003
+
-
PNP Transistor
C
×
FAN
100%
W83637HF
Revision 1.3