Feature Integration Technology Inc.
Fintek
F75373
5.4.3.3 PWMOUT Duty-cycle operating process
In both “FAN SPEED” and “TEMPERATURE” modes, F75373S adjust PWMOUT duty-cycle according to current
fan count and expected fan count. It will operate as follows:
(1). When expected count is FFFFh, PWMOUT duty-cycle will be set to 00h to turn off fan.
(2). When expected count is 0000h, PWMOUT duty-cycle will be set to FFh to turn on fan with full speed.
(3). If both (1) and (2) are not true and KEEP_DROP_DUTY(see INDEX 60h) is set to 0,
(a). When PWMOUT duty-cycle decrease to DROP_DUTY(≠ 00h), obviously the duty-cycle will be 00h next,
F75373S will keep duty-cycle at 00h 3 seconds1. After that, F75373S starts to compare current fan count and
expected count in order to increase or decrease its duty-cycle. This ensures that if there is any glitch during the 3
seconds1 period, F75373S will ignore it.
(b). When PWMOUT duty-cycle increase from 00h to RAISE_DUTY(≠ 00h), F75373S also will keep duty-cycle
at RAISE-DUTY 3 seconds1. After that, F75373S starts to compare current fan count and expected count in order
to increase or decrease its duty-cycle. This ensures that if there is any glitch during the 3 seconds1 period,
F75373S will ignore it.
Note 1: The period can be programmed at INDEX 6Eh.
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V0.25P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
