LB11852FV Datasheet, PDF (8/12 Pages) Sanyo Semicon Device – Monolithic Digital IC For Fan Motor Single-phase Full-wave Pre-driver with Speed Control Function

Description of Speed Control Block
1. Speed control diagram
(RPM)
LB11852FV
The slope is determined by the RC pin constant.
CR time constant small
CR time constant large
Rotational speed
Minimum speed
0%
Determined by LIM pin voltage
Small ← CTL signal (PWMDUTY) → Large
Large ← EO pin voltage (V) → Small
100%
Minimum speed setting rotation
On-duty small
CTL pin
Variable speed
Full speed
On-duty large
5VREG
EO pin
0V
LIM voltage
EO voltage
2. Timing at startup (soft start)
VCC pin
CTL pin
SOFT pin
Stop
Stop
Full speed
Soft start
The slope changes depending on the
capacitance of the SOFT pin
(large capacitance large slope).
Full speed
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