1995VLX/VL2X/BLX4.0 DESCRIPTION OF CIRCUIT
The IC501(CPU) will detect polarity and
4.0 DESCRIPTION OF CIRCUITfrequency of input H.V. Sync.. The CPU will
determine the mode of input timing (preset or
1.Power supply circuit
users mode) and load mode data from
The power supply is a serial & universal ACIC502(EEPROM). The output of IC501 were
input switching power supply. The start upconnected to other function circuit (IE. H-size,
circuit (Q101) will provide a DC voltage forH-phase, V-size, V-center?). Also, the user
PWM (Pulse Width Modulation) IC(IC101)can adjust picture from keyboard and the data
when power on. While IC101 works normal,will be saved into IC502 automatically. For the
Q101 will be cut off by the DC voltage. TheO.S.D. mode, when O.S.D. manual is active
IC101 will Auto-detect output voltage of powerCPU will inform the O.S.D IC (IC603) to send
supply from Pin2 and correct the duty cycle ofO.S.D BLK signal to blank the video signal
Pin6 output pulse to compensate the variationfrom VGA card, and the O.S.D. IC will send
of output voltage.O.S.D. R.G.B. Video signal to show the O.S.D.
manual on screen.
The output of IC101 Pin6 connected to power
MOSEFET to drive the power transformer
6.H.V. regulation circuit
T101. When power MOSFET is on, the energy
stored in the primary winding of T101. Once The IC402 is a P.W.M IC, Pin7 is P.W.M
MOSEFET is off, the energy transfer to theoutput which connected to output transistor
secondary and charges the output capacitor toQ401 and Q402 via buffer driver
get the stable DC voltage.Q407,Q409,Q410,Q408. The Q402 is H.V.
output switching transistor, Q401 and D401 are
2.Oscillation circuitdamper device provide the path of damper
current. IC401 is a feedback amplifier, the
The functions H-size, H-phase, V-size, V-
feedback voltage from FBT Pin11 connected to
center, Side-pin, Parallel?.are designed inside
IC401 Pin5, and output is from pin1 which
into IC301. The Pin2 is X-RAY protect input.
connected to IC402 for P.W.M the duty cycle
When H.V output circuit is abnormal (H.V too
control.
high) the X-RAY protect circuit will shut off the
horizontal output, H.V. also will be shut down.
+7.Video output circuit
The Pin6 is B control driver output. The Pin8
is horizontal square wave output drivesVideo circuit consists of video preamplifier
horizontal output. The Pin11 is parabolicIC601 and output cascade amplifier IC604.
output. The Pin12,13 are vertical output. TheIC601 is a video processing IC equipped with
Pin14 & pin15 are V-SYNC & H-SYNC input.three DC amplifiers to pre-amplify R.G.B.
The Pin17 is vertical blanking output. Thesignals from 0.7V to 4.2V.
Pin23,24 for vertical oscillator. The Pin28,29
The R.G.B. GAIN & BIAS control signal are
for horizontal oscillator. The Pin30 is soft start.2
from IC501 via IC-bus to DAC IC601. The
IC601 control to video gain. The output of pin
3.Vertical output circuit
24, 25, 26 are connected to BIAS circuit of
The Pin12 & 13 of IC301 are vertical synceach R.G.B. signal?s amplification and thus
output connected to IC201 (Amplifier), Pin5 ofachieve a well balanceable white picture.
IC201 is vertical amplifier output drives the
The O.S.D. R.G.B. (Pin4, 9,13 of IC601) is the
vertical deflection directly.
input of O.S.D. Video signal. The IC604 is
R.G.B. drive to capable of driving CRT.
4.Horizontal output circuit
+
The DC-DC is to generate a DC voltage (B)
for horizontal output circuit. The CPU(IC501)
controls the H. size adjustment function of
2
IC301 via the IC Bus. The output of IC301
(Pin6) connected to gate of Q311 to make the
Q311 switching. When Q311 is ON, the
energy stored in L305 and the energy released
+
via D313 when Q311 turned OFF. The B
applied to Horizontal Yoke and supply the
power for horizontal deflection. The more the
+
B,will get the bigger the horizontal size.
5.Micon circuit
CTX5 |
ACEC
