lb11850va Sanyo Semiconductor Corporation, lb11850va Datasheet - Page 8

• Manufacturer Part Number: lb11850va
• Description: For Fan Motor Single-phase Full-wave Pre-driver With Speed Control Function
• Manufacturer: Sanyo Semiconductor Corporation

Description of Speed Control Block
1) Speed control diagram
2) Timing at startup (soft start)
Minimum speed
Rotation speed
CTL pin
(RPM)
EO pin
5VREG
SOFT pin
V CC pin
CTL pin
0%
0V
ON-Duty small
Minimum speed
setting rotation
CR time constant small
The speed slope is determined by the constant of the RC pin.
Stop
Stop
Small ← CTL signal (PWMDUTY) → Large
Large ← EO pin voltage (V) → Small
Full speed
LB11850VA
Soft start
The slope changes according to the capacitance of SOFT pin.
(Large → Large slope)
Full speed
Variable speed
Determined by LIM pin voltage
CR time constant large
Full speed
ON Duty large
100%
EO voltage
LIM voltage
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