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2
.
H and V processor
2.1 Auto Sync Deflection control and B+ control circuit Horizontal and vertical sync through IC401 STV9118
transmit
﹒
Deflection controller IC401 STV9118
:
a
﹒
The control input
(
V-position
﹐
H-position
﹐
V-size
﹐
H-size
﹐
Pincushion
﹐
Pin-Balance
﹐
Trapezoid
﹐
Parallelogram. TOP Corner. Bottom Corner. Zoom, moiré
)
are use I
2
C control
﹒
b
﹒
SYNC
input
:
H-sync
(
pin1
)(
From IC301 pin33
)﹒
V-sync
(
pin2
)(
From IC301 pin32
)
﹒
c
﹒
Output
:
∗
B
+
Driver
(
pin28
)
﹒
∗
H-Driver
(
pin26
)﹒
∗
EW-Driver
(
pin24
)﹒
∗
Focus
(
pin32
)
﹒
∗
V out
(
pin23
)
﹒
2.1.1
Horizontal
input
control
a
﹒
Then take a HFLB pulse from FBT pin5 to IC401 for AFC to make pin 26 H-driver output
control
Horizontal
circuit
﹒
b
﹒
Pin 6 and pin 8
(
C429
﹐
R471
)
control horizontal hold in range
﹒
2.1.2
Vertical
input
control
a.
V-sync outputs from MCU IC301 pin32 to IC401 pin2
﹐
then release V-out from pin23
﹐
pin 13 to
IC501
KA2142
pin1and
pin7
﹒
b.
V-output to vertical hold in range is controlled by pin22
(
C508
)﹒
2.1.3
B
+
input control
Take a pulse from T401 pin 5 and accumulates to become a DC voltage via D423
﹐
C437 and R4408
to IC 401 pin14, pin15 output pulse by pin28 via Q202 to boost converter circuit.
2.2
Vertical
deflection
a
﹒
IC401 pin23 and pin13 output to IC501
(
KA2142
)
pin7 and pin1
﹐
then IC501 pin 6 make vertical
deflection output
﹒
b
﹒
Vertical
blank
:
IC501 pin4 take a blanking pulse
﹐
After passing Q501 buffer can supply video blanking
signal
﹒
2.3
Boost
converter
The Booster converter mainly composes of n-channel MOSFET Q202 chock L201 capacitor C202, C212 and
rectifier diode D204. IC401 pin28 B
+
driver output via Q204, Q205, Q202 to driver Booster converter
and provide a DC-voltage to provide B
+
H-output circuit use
﹐
As H-freq. change
﹐
IC401 pin28 B
+
-driver
will change its output
﹐
Booster converter will also change the B
+
it provides
﹐
H-freq. will varies from
30K
~
96KHz
﹐
B+ will varies from 55V ~ 195V
﹒
2.4 X-RAY radiation protection
FBT pin 5 output one pulse to pass through D417 and C424 integration DC voltage
﹐
and through D418 IC401
pin 25
﹐
when anode voltage abnormal increase
﹐
FBT pin5 and IC401 pin25 voltage to be increased
﹐
too
﹒
As IC401 pin25
≅
8V
﹐
IC401 X-RAY protection circuit immediately active
﹐
H-driver, B-driver and V-out no
output
﹒
The X-RAY radiation protection circuit used in this monitor is a latching type the monitor will shown
down and continue until turn-off the monitor with power switch
﹒
20
ViewSonic
Corporation
Co
nfidential
-
Do
Not
Copy
G90f/B-3
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