4-Wire Pulse Width Modulation (PWM) Controlled Fans Specification

Fan Speed Control
17
Figure 6 Type C, Operation below Minimum RPM, Min, RPM = Starting RPM
Speed vs. PWM Duty cycle
0
5
10
15
20
25
30
35
0 5 10 15 20 25 30 35
PWM Duty Cycle
Example Min.
RPM
Example Min.
PWM
% of full spe e d
The minimum fan
speed specified is
also the minimum
fan starting speed.
The fan may
continue to run at
speeds below the
minimum speed,
but will not start at
that speed.
Fan speed as PWM duty
cycle is being reduced
Fan speed
as PWM
duty cycle
is being
increased
§