Epson LX-810 Technical Manual

REV.-A
WWF :
.-.-J---------.---
---------
0{
I
VRS
I
-.-.-- ------- ------- ?------ ------- -
1
Vb :
,
------ : ----- . : - . ---- s -----------------------
Q{
#
VT
1
,
0
----
;-----------------
0
VG
8
0
1
Zvcc --- ~; ‘4
—
0{
,
,
VG
0{
VF
,
1
; 1P
o~
km
o
o{
IWF
o
0
Icc
[
o
. --- L -----------
,
,
,
.
,
,
I
,
----------------
#-
------
------
b
------
t
I
t
I
*
F
t
1
,
1
t
i
I
t
I
I
t
, -----------------
-------
.. -----
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,
1
1
A
,
4
1
I
to tl t2 t3
Figure 2-34. Waveforms
The circuit’s constant current control process is shown above.
.p
. .,
Peak current detection (to-t 1)
(1) When excitation input IN goes ON, so does MOS FET Q 1. The A-coil excitation current I
ON then
flows along route –.
(2)
As I
ON increases, so does the voltage at R30.
(3)
When
R30 voltage exceeds Vref, COMP 1 inverts, and the TD voltage falls to near zero.
(4) When
VTD drops below the COMP2 threshold voltage, COMP2 inverts.
(5)
COMP2 inversion causes Q1 gate voltage to go LOW, and Q1 goes OFF.
Chopper off time (t
l-t2)
(6)
When
Q1 goes OFF, reverse potential is generated in the motor coil, causing the coil current
route to switch from I
ON to IOFF.
2-30

Epson LX-810 Specifications

General

Print Method	Impact dot matrix
Number of Pins	9
Character Sets	96 characters (USASCII)
Line Spacing	1/6 inch
Paper Path	Rear
Interface	Centronics parallel
Noise Level	55 dB (A)