W83L786NR Datasheet, PDF (19/50 Pages) Winbond – H/W Monitoring IC

W83L786NR/ W83L786NG
7.6.2 Fan Speed Control
The W83L786NR/NG provides two sets for PWM/DC fan speed control. The duty cycle of PWM or the
output voltage of DC can be programmed by a 4-bit register. There are four mode to control fan speed
which are set by programming CR80 [3:2] and CR [5:4], and default are FAN_SET mode.
7.6.2.1. Default Fan Speed Setting
There is a pin to set the default value for fan speed control by adjusting external serial resistors. After
power up, the default value will be stored in CR90 (FAN_SET mode). The figure and table are shown
below.
VCC
Ra
FA N _SET
Rb
SECTION
3
2
1
0
FAN SPEED RATE
100﹪
81﹪
62﹪
43﹪
Figure 8 OFFSET Setting
RA
9.1K
4.7K
9.1K
×
RB
×
9.1K
4.7K
9.1K
7.6.2.2. PWM Mode
Duty − cycle(%) = ^{Programmed 4 - bit Register Value} ×100%
16
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