lb11850va Sanyo Semiconductor Corporation, lb11850va Datasheet - Page 12

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

(2) Movement along the Y-axis (resistance divided between CVO and V CC )
(Example) In the case where the characteristics change from ones with the origin point (0%, 0 rpm) to ones where the
With CVO = 4.25V, find the resistances at which CVI = 5V.
The ratio of CVO-CVI: CVI-GND is 0.75V: 7V = 1: 9.3
Based on the above, the resistance is 20kΩ between CVO and CVI and 180kΩ between CVI and V CC .
(Due to the current capacity of the CVO pin, the total resistance must be set to 100kΩ or more.)
Furthermore, the slope changes. (In the case of the example given, since the resistance ratio is 1: 9.3, the slope is now
9.3/10.3 = 0.9 times what it was originally.)
If necessary, change the resistance of the RC pin, and adjust the slope.
Motor
at maximum speed
speed at a duty ratio of 25% becomes 0 rpm:
First, obtain the CVO pin voltage required for the CVI voltage to be 5V at 25%.
CVO = 5-(3×duty ratio) = 5-(3×0.25) = 5-0.75 = 4.25V
(RPM)
0%
R4
R5
V CC
C
LIM
CTL
SOFT
CVI
CVO
LB11850VA
Move in the direction
of the Y-axis
CTL Duty(%)
CTL
VREF
100%
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