LG LB500K-GL Service Manual page 11

DESCRIPTION OF BLOCK DIAGRAM
1. Scaler One chip IC(GMZAN-2, U201)
GMZAN-2 (U201) is one chip IC which it supports four internal function blocks of Video Amp, PLL,
A/D converter and Video processor.
Video signal (0.7Vp.p) clamped through C207, 208, 209 with matching IC's proper cut off voltage.
This signal is processed as a proper 8 bit digital signal by U201's amplifying, phase locking, A/D converting,
and scaling operations.
U201 outputs 36 bit two channel RGB data and control signals (Clock, Horizontal and Vertical sync, and
Data Enable) as LCD panel's input signals.
2. System Controller (Microprocessor) Circuit
1) Microprocessor (U501) distinguishes polarity and frequency by calculating horizontal and vertical sync input
from signal source.
2) Microprocessor (U501) carries out power control by sending power-down trigger signal to each IC.
3) Microprocessor (U501) communicates with EEPROM (U502), and GMZAN-2 (U201)
through IIC(2 lines) or 4 bit bus line. It makes all devices operated properly.
4) Microprocessor (U501) let User adjust screen by OSD function.
4. DC/DC block
This block is composed of regulators which supplies 2.5V and 3.3V.
Each regulator's source power is 5VR from LIPS(LCD Inverter and Power Supply) block.
U806 supplies 2.5VD and 2.5VA and U802 supplies 3.3VD, 3.3V_AD, and 3.3V_PL powers to GMZAN-2's
internal PLL, ADC, Pre-amp, and scaler by dropping down 5VR.
U805 supplies MODPWR-3.3V for LCD module's operation by dropping down 5VR.
5. LIPS Block (LCD Inverter and Power Supply)
This block supplies DC voltages of 5VS to interface board and 12V to inverter by converting AC input voltage
of 100~240Vac.
Converting method is SMPS(Switching Mode Power Supply).
Inverter on/off signal from microprocessor makes inverter turned on or off .
DIMADJ signal from microprocessor does inverter's current adjustment for Brightness control.
(AUO Module)
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