BU52040HFV_10 Datasheet, PDF (8/13 Pages) Rohm – Bipolar Latch Hall IC

BU52040HFV
Technical Note
Detection of Rotation Direction
1) Mounting angle = Φ/4
Clockwise Rotation
Magnetic field applied to IC A
Magnetic field applied to IC B
Bop
S
rotation angle
N
Brp
Counterclockwise Rotation
Magnetic field applied to IC A
Magnetic field applied to IC B
Bop
S
rotation angle
N
Brp
Hall IC A
output
High
Hall IC A
output
High
Low
Hall IC B
output
High
Low
Hall IC B
output
High
Low
Low
Clockwise turn: Output of IC B is low when
output of IC A becomes high
Counterclockwise turn: Output of IC B is high
when output of IC A becomes high
2) Mounting angle = ¾Φ
Clockwise Rotation
Magnetic field applied to IC A
Magnetic field applied to IC B
Bop
S
S
rotation angle
N
Brp
N
Counterclockwise Rotation
Magnetic field applied to IC A
Magnetic field applied to IC B
Bop
rotation angle
Brp
Hall IC A
output
High
Low
Hall IC A
output
High
Low
Hall IC B
output
High
Low
Clockwise turn: Output of IC B is high when
output of IC A becomes high.
Hall IC B
output _High
Low
Counterclockwise turn: Output of IC B is a low
when output of IC A becomes high.
Because the IC measures changes in magnetic field every 1200 µS, the IC cannot detect changes in rotation at speeds
exceeding this period.
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8/12
2010.01 - Rev.B