AK8778B Datasheet, PDF (6/12 Pages) Asahi Kasei Microsystems – HALL EFFECT IC FOR PULSE ENCODERS

[AK8778B]
Behaviors of internal signal A,B and output signal F, D when a rotating magnetic field is applied on AK8778B
F signal (pulse) is correspond to the result of EX-OR operation of internal signal A and B. And signal D (direction)
is calculated by the state of internal signal A and B.
Direction changed
Direction changed
BopV
Vertical M.F.D.
0
BrpV
t
BopH
Horizontal M.F.D.
0
BrpH
t
Supply voltage V_DD
0
t
Internal signal A
(Vertical)
t
Internal signal B
(Horizontal)
t
F (Pulse)
0
t
D (Direction)
0
t
Undefined (High or Low)
Signal F, D is determined.
Figure 4. Behaviors of internal signal A,B and signal F, D when a
rotating magnetic field is applied on AK8778B
*M.F.D. is Magnetic Flux Density.
Note) Signal D is determined after one signal F pulse is sent out. The indeterminate output state appears only in the
powering up of this device.
MS1466-E-00
September 2012
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