Epson LQ-2550 Technical Manual page 83

2 . 2 . 7 + 3 5 V C u r r e n t L i m i t i n g a n d V o l t a g e R e g u l a t o r C i r c u i t s
Figure 2-30 shows the +35 V current limiting and voltage regulator circuits. This circuits is controlled "+;""
by switching regulator IC TL594*1 (IC2).
waveform from the oscillator section, using a PWM comparator, and turns on TR 1 and TR2 only when
the sawtooth waveform is larger than the outputs from both amlifiers.
Refence voltage for
comparison detection
section
— — . — — . .
\
I I Current
,
I section
%
I
I
I
I
1690
I
1%
I
C30 ,
1 Kfl
Figure. 2-30. +35 V Current Limiting
Voltage detection
section
.—— —— — — - 1 0 3 5
f
T
R41
R42
- — — —— —.
—
T2
"3
5 "
8
\ *
I
+35
—
I
16 15 14
I
EA1
1 2
C27
10OPF
100K(I
1%
C26 ,
-
C 2 9
0. IuF
and Voltage Regulator Circuits
2-36
+ 1 2
A
13 12 11 10
C
'
GND
3 4 5 6 7
C 2 8 R32
1%
2.1 Kfl
1%
9
8
—
I