LG StudioWorks 560LS, Service Manual, Page: 12 / 34

DESCRIPTION OF BLOCK DIAGRAM
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1. Scaler One chip IC(GMZAN1, U3)
GMZAN1 (U3) 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 C44, 45, 191 with matching IC’s proper cut off voltage.
This signal is processed as a proper 8 bit digital signal by U3’s amplifying, phase locking, A/D converting,
and scaling operations.
U3 generates Clock, Horizontal and Vertical sync, Data Enable signals as LCD Panel’s input signals.
2. 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.
3) Microprocessor (U4) communicates with EEPROM (U1), and GMZAN1 (U3)
through IIC(2 lines) or 6 bit bus line. It makes all devices operated properly.
4) Microprocessor (U4) let User adjust screen by OSD function.
3. DC/ DC Converter
This circuit supplies DC power for each device needing DC voltage of 3.3VD, 3.3V_AD, 3.3V_PL, and 5VS.
L4973D5.1(U13) , the DC/DC controller IC converts input 24Vdc into 5VS and 3.3Vdc with peripheral circuit
composed of Inductor (L11), condensing components (ZD5, C72), and Regulators(U2, U7, U24).
MODPWR(3.3V) for LCD module power is switched by U12, switching FET, controlled by Microprocessor.
3.3VD, 3.3V_AD, and 3.3V_PL for GMZAN1 (U3) is switched by U5, switching FET, controlled by
Microprocessor for Power saving.