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BLOCK DIAGRAM
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POWER CORD
15-pin D-SUB SIGNAL CABLE
POWER
SUPPLY
CONTROL PCB
INVERTER PCB
MAIN LOGIC
PCB
LCD MODULE
System Block Diagram
Page 2
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BLOCK DIAGRAM FOR Flatron LCD 577LM/ 577LH/ 576LU
24bit
Video
Digital
Video Processor
MX88L284
R
G
B
HS/VS
Dot clock
System Controll er
MC68HC05BD48
Power Connector
DC/DC
Converter
(L4973D5.1)
REG
REG
REG
REG
REG
Analog
Switch
+5V
+5V Module
I2C
Control
EEPROM
(24LC08B)
Link Connector
P anel Link
Transmitter
( Sil 100 )
Control
Signal
TMDS
SDA/SCL
15PIN
3 ROW
D-SUB
PRE AMP+ ADC
+PLL
TDA8752B
8 BIT
8 BIT
8 BIT
H-sync
Clamp
Buffer
+24V
GND
+5VST
+5VPLL
+3.3VD2
+3.3VD
+5V
+5V
+5VPLL
+5VANA
5VST
+3.3VD
+3.3VD
V-sync
ADDR
DA TA
/RD
/WR
MEMORY
2M Byte * 3
I2C
+3.3VD2
H-sync
V-sy nc
Control
Communication
8bit
16
10
DC/DC
Converter
(L4973D5.1)
USB HUB IC
(TUSB2046B)
UPSTREAM
DOWN STREAM * 4
< MAIN >
+24V
+5V
DATA
REG
+3.3V
< USB >
DC/DC
Converter
(L4973D5.1)
AUDIO AMP
TDA7496L
+13.3V
Audio
signal
input
L
R
MUTE
V+
V-
SHUT
DOWN
< AUDIO >
- Option
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DESCRIPTION OF BLOCK DIAGRAM FOR 577LM/ 577LH/ 576LU
1. Video Amp & PLL & A/D Converter Circuit
TDA8752 (U1) is one chip IC which it supports three function block of Video Amp, PLL and A/D converter.
Video signal (0.7Vp.p) clamped through C6, 7, 16 inputs to U18’s R, G, and B pins. The signal level is 0.7Vac added
3Vdc. This signal is processed as a proper 8 bit digital signal for input of MX88L284 (U5) by U1’s amplifying, phase
locking, and A/D converting operation.
U1 generates clock and horizontal sync for MX88L284 (U5) with D-sub (J1)’s input horizontal sync signal.
MX88L284 (U5)’s clamp output makes U1 keep video signal’s black level constantly regardless of various input video
signals.
2. Macronix Circuit (Scaler chip)
The MX88L284 (U5) gets the video signal converted analog to digital from U1, and carries out four function of image
processing that interpolates input signal less than 1024x768 resolution to that of 1024x768 resolution, displays one to
one image without interpolation, mixes OSD(On Screen Display) signal by interfacing with internal OSD IC, and
controls two memories(U6, 7) as frame converter. U5 outputs signals of HSYNC-OUT, VSYNC-OUT, DEN, CLKAODD, and each 8 bit R, G, B to transmitter IC (U16).
3. Memory Circuit
2M byte SDRAM(U6, 7) is used as a frame converter for supporting up to 85 Hz frame rate and controlled by
MX88L284(U5). The control signals are CKA, CLK, UDOM, LDOM, /WE, /CAS, /RAS, /CS, /BA.
4. Panel-Link Circuit
Panel link transmitter (U16) delivers digital signal to the receiver inside LCD module by method of abstraction.
The abstracted signals are pairs of TX0+-, TX1+-, TX2+-, TXC+- of which voltage swing is 0.5V each.
Its swing is similar to LVDS (Low Voltage Differential Signal).
Transmitter (U16) gets signals of HSYNC-OUT, VSYNC-OUT, DEN, CLKA-ODD from U5, and outputs TMDS
(Transition Minimized Differential Signal) through TX pins.
When PD pin’s input is low, transmitter goes to power down mode.
5. System Controller (Microprocessor) Circuit
1) Microprocessor (U4) distinguishes polarity and frequency by calculating horizontal and vertical sync input from
signal source.
2) Microprocessor (U4) carries out power control by sending power-down trigger signal to each IC.
U1, U5, U16, and U13 has PD(Power-down) pin which operates at active-low or high.
It also outputs signal to turn inverter on and off for lamp control.
3) Microprocessor (U4) communicates with EEPROM (U3), TDA8752 (U1), and MX88L284 (U5 through IIC(2 lines) or
8 bit bus line. It makes all devices operated properly with communication channel.
4) Microprocessor (U4) let User adjust screen by each OSD function.
6. DC/ DC Converter
This circuit supplies DC power for each device needing DC voltage of+3.3VD, +3.3VD2, +5V, 5VPLL, and 5VST.
L4973D5.1(U13) , the DC/DC controller IC converts input 24Vdc into +5Vdc and +3.3Vdc with peripheral circuit
composed of Transformer (TRANS1), condensing components (ZD5, D6, C201, C26, C72, C73) and Regulators
(U17, U2, U24). 5VST is supplied for Microprocessor through regulators (U11, U22).
+5VMOD for LCD module power are switched by U12, switching FET, controlled by Microprocessor.
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