Carriage Motor Driver Circuit; Table 2-11. Connection Between Input And Output Signals - Epson Stylus 820 Service Manual

Stylus Color IIs / Stylus 820

2.3.2.3 Carriage Motor Driver Circuit

Carriage motor driver IC A2919 (IC12) outputs a constant current to drive the carriage motor. Gate
array E05B08 (IC1) decides the motor phase and speed, and then sends a signal to the carriage motor
driver IC using a 2-bit signal transmission line. (In the Stylus Color printer, 4-bit serial data was
transmitted from the gate array to the driver IC.)
The carriage motor is controlled using a 1W1-2 phase method. 1W1-2 phase is
Stylus Color printer, the carriage motor was controlled using 2W1-2 phase.) The table below shows the
motor drive method along with the micro steps.
Table 2-10. Motor Drive Method (Clockwise Direction)
Step
1
^
^
^
2
^
^
^
3
^
^
^
4
^
^
^
Note:
One feature of driver IC A2919 is that it can gain constant torque by small movements of the
carriage motor if 1/3 × 1TRIP (TRIP = established current). Therefore, the driver sequence
reflects that coefficient in the above table.
Also, the phase drive signal uses only two ports of IC A2919. The table below shows the connection
between the input and output signals.

Table 2-11. Connection Between Input and Output Signals

Phase (Input Port)
H
L
Note:
As shown above, two output signals are decided by only one input signal.
Rev. A
Phase A
+2/3
+1/3
0
–1/3
–2/3
–1
–1
–1
–2/3
–1/3
0
+1/3
+2/3
+1
+1
+1
OUT A
H
L
Operating Principles
⁄
1
the 2-2 phase. (In the
4
Phase B
+2/3
+1
+1
+1
+2/3
+1/3
0
–1/3
–2/3
–1
–1
–1
–2/3
–1/3
0
+1/3
OUT B
L
H
2-23