Epson 2180 - LQ B/W Dot-matrix Printer, Service Manual

Page: 28 / 56

LQ-2180 Revision A
Operating Principles Control Circuit 28
2.1.4 CR Motor Driver Circuit
The CPU (IC4) directly controls the phase change of the CR motor.
SLA7024M (IC11), the driver IC for the CR motor, performs bi-polar
constant current drive to detects the amount of current flowing into the
motor and chops the current supplied. With this operation, current
flowing into the motor coil is regulated.
The CR motor driver circuit is as shown below:
Figure 2-5. CR Motor Driver Circuit
2.1.5 PF Motor Driver Circuit
The gate array (IC3) manages the PF motor control. The driver IC for
the PF motor, which enables the constant current drive, receives the
phase change signal directly from the gate array and determines the
phase to which current flows.
The PF motor driver circuit is as shown below:
Figure 2-6. PF Motor Driver Circuit
C P U ( I C 4 )
P G O 0
P G O 1
P G O 2
P G O 3
1
2
3
4
6
5
1 7
1 6
I N A
I N - A
I N B
I N - B
A
- A
B
- B
S L A 7 0 2 4 M ( I C 1 1 )
C N 1 1
C R A
C R - A
C R B
C R - B
E 0 5 B 4 2 ( I C 3 )
P F I 0 A
P F I 1 A
P F I 0 B
P F I 1 B
1
2
3
4
C N 1 1
C R A
C R - A
C R B
C R - B
P H A S E A
P H A S E B
1 2 2
1 1 9
2
1
2 3
2 4
I N A
I N - A
I N B
I N - B
A
- A
B
- B
A 2 9 1 7 ( I C 1 2 )
4 3
2 6
6
3
1 8
2 1