M54687FP Mitsubishi, M54687FP Datasheet - Page 5

• Manufacturer Part Number: M54687FP
• Description: Bi-DIRECTIONAL MOTOR DRIVER WITH GOVERNOR
• Manufacturer: Mitsubishi

Speed Control Method
(1) Speed Control Method I (See the application circuit drawing.)
(2) Speed Control Method II (to increase the motor rotation number)
In the external circuit above, the voltage across motors is almost
determined by the ratio of ‘RS+RT’ to ‘RT’ and, therefore, a value
set for the voltage across motors is not so large.
As method (1) of speed control I, the rotation number can be
controlled.
However, the following relations must be satisfied:
RT
RS+RT
For PLAY/REV
Rotation number can be expressed by the following formula:
N=
Where:
Motor generation constant: Ka, Motor armature resistance: Ra,
Rotation number: N
K: Current proportional constant, IB: PSC pin bias current,
Ia:motor current
RT, RS: External resistance
In addition, to set the rotation number with RS, external
resistance RT is generally set as follows:
RT
For FF/REW
Note that the rotation number is basically controlled with the
same expression as formula (1) but different reference voltage
V
However, V
ref
RT+RS
Ka
1
and different bias current IB are to be used.
PSC1
K x Ra
{IB
R
RT
Control signal
•
RT+V
ref
O
=
L
1
RT
5VR+0.5
ref
(1+
RS
M
S
RT+RS
RT
O
2
)+la(
RT
PSC2
RT
K
-Ra)}
L-G
V
• • • • • •
R
(1)
V
P-G
CC
Bi-DIRECTIONAL MOTOR DRIVER WITH GOVERNOR
(3) Speed Control Method III (to increase the precision of forward
The above two applications cannot make fine adjustments in
forward rotation and reverse rotation (because the external
resistance is shared with the forward rotation and reverse rotation).
Fine adjustments can be made for each of forward rotation and
reverse rotation if the external circuit is set as shown in the drawing
above.
This external circuit is also available to change the speed of
forward and reverse rotation.
The control method adopts the same formula as formula (1).
However, the following relations must be satisfied:
RT+RS
RT
rotation and reverse rotation)
RT1 or RT2
PSC1
R
RS1 or RS2
Control signal
MITSUBISHI <CONTROL / DRIVER IC>
O
L
1
RS1
RT2
M
S
RS2
RT1
O
2
PSC2
M54687FP
L-G
V
R
V
P-G
CC