LB1991V_09 SANYO [Sanyo Semicon Device], LB1991V_09 Datasheet - Page 6

• Manufacturer Part Number: LB1991V_09
• Description: For Fan Motor 3-phase Brushless Motor Driver
• Manufacturer: SANYO [Sanyo Semicon Device]

Overlap Generation and Calculation Method
Calculated center point
Overlap Generation
Overlap Calculation
Absolute voltage
Since the voltage generated in the amplitude control block is, taking the center point as the reference, 2 × <overlap> ×
(1/2 V S − V X ) on one side, the intersection point of the waveform will be <overlap> × (1/2 V S − VX) from the center
point.
To clamp that waveform at (1/2 V S − V X ) referenced to the center point the overlap must be:
A/B × 100 = <overlap> × 100 (%).
• Upper side overlap
• Lower side overlap
Calculated center point: V N =
Since A = Vα − V N , B = V S − V XH − V N , the upper side overlap will be:
Which can be calculated as:
Since C = V N − Vβ, and D = V N − V XL , the lower side overlap will be:
<overlap> =
Which can be calculated as:
<overlap> =
V S V XH
V N
V XL
V S
V
V
0
C
D =
A
B =
=
=
((V S − V XH + V XL )/2) − V XL
(V S − V XH ) + V XL − 2Vβ
2Vα − (V S − V XH ) − V XL
V S − V XH − ((V S − V XH + V XL )/2)
((V S − V XH + V XL )/2) − Vβ
(V S − V XH ) − V XL
(V S − V XH ) − V XL
Vα − ((V S − V XH + V XL )/2)
(V S − V XH − V XL )
Electrical
angle
180
2
A
C
×100(%)
×100(%)
LB1991V
D
×100
+ V XL =
B
×100
(V S − V XH + V XL )
2
Upper side
residual voltage
Lower side
residual voltage
O.L (
V S
V S
Upper side clamp potential
2
Lower side clamp
potential
V XH
Time
V S
2
V XH
V XH )
V S V XH
V XL
V XL
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