Carriage Motor Driver Circuit; Figure 2-23. Carriage Motor Driver Circuit Block Diagram - Epson Stylus 1500 Service Manual

Stylus 1500 Service Manual

2.3.2.3 Carriage Motor Driver Circuit

The SLA7043M carriage motor driver IC (IC15) outputs a constant current to drive the carriage motor in the
printer mechanism. The E05B16 gate array (IC2) determines the motor phase and speed and then sends a
signal to the carriage motor driver IC using the 4-bit serial transmission line.
The first bit indicates the motor rotation direction. The other three bits are current duty data for the motor
speed of each printing sequence. The SLA7043M motor driver can select the reference voltage based on these
three current duty data bits. It also receives these signals by two serial transmission lines for the two motor
phases (A and B). As a result, the carriage motor can drive in micro-step sequences (a minimum of 1/720
inch).
E05B16
(IC2)
X CR CL K
X CR STB
CR AS ERI
CRBSERI
C R V 0
~ C RV 6

Figure 2-23. Carriage Motor Driver Circuit Block Diagram

The SLA7043M motor driver reads the 4-bit data using four clock counters from the E05B16 (IC2) clock.
Each bit is read at the falling edge of these clock pulses. As a result, received serial data is placed in the shift
register and then shifts the latch register. When the strobe pulse becomes active from the E05B16 (IC2)
clock, serial data is moved into the reference voltage selection circuit and the voltage is changed. Therefore,
when the printer is in constant-speed mode, this strobe pulse becomes inactive.
Rev. A
SL A7 0 43 M
81
5
C L K A
16
C L K B
2
80
STBA
13
STBB
101
6
D ATA A
17
102
D ATA B
+5 V
CRV 3
R E FA
14
R E FB
(IC15)
CR Mo tor
1
CR A
A
8
C R _ A
A
11
B CR B
18
C R _ B
B
+42 V
C R C O M
Operating Principles
2-19