Inverter Circuit - Acer P221W Service Manual

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protection, goes into U102(RTD2120) #5.
- Signal DDC_SDA (series data) inputs via CN103#12, and then passes through EP104 for ESD
protection, goes into U102(RTD2120) #8.
- Signal TTL vertical sync. (Vsync) inputs via CN103 #14, and then clamped by EP102, passes
through R164, and then goes into IC U103 (RTD2553VH) #40.
- Signal TTL horizontal sync. (Hsync) inputs via CN103 #13, and then clamped byEP103, passes
through FB104,R166, and then goes into IC U103 (RTD2553VH) #39.
- CN103#5 is defined as cable detect pin, this detector realize passes through R159 Pull hight, go into
U102#24.
- U103 power is supplied by PC via CN103#9, or supplied by Monitor self.
- U105 is an EEPROM IC which is memory and OSD data saved in it.
3 .2.2 Buttons Control
- Button "Power" on right side bezel connects to U102(RTD2120) #9 through R105, via CN101#8.
- Button "Left" "Right "is ADC key,when press "Left" key, U102(RTD2120)#21 detect about
1.0~1.5V, then U102(RTD2120) know it is "Left" been pressed; when press "right" key,
U102(RTD2120)#21 detect 0V, then U102(RTD2120) know it is "Right" been pressed;
"MENU" "AUTO" on left side bezel connects to U102(RTD2120) #14,#22 through R110,R201, via
CN101 #1, #3.
- LED Indicator on Front Bezel
a. When press button "power", U102(RTD2120) #1 sends out a low potential, via R106, flow to
CN901#4 on keypad, LED amber on until "ACER" logo over,then U102(RTD2120) #1 sends out
a high potential, LED amber off .and then U102(RTD2120) #48 sends out a low potential,LED
green on.
b. When in "Suspend" mode, U102(RTD2120) #1 sends out a low potential, via R106, flow to
CN901#4 on keypad ,LED amber on.
3.2.3 Realtek CHIP U103 (RTD2553VH)& U102(RTD2120)
- U103 (RTD2553VH) #73~#82 output 8 bit even LVDS digital data to panel control circuit through
CN105.
- U103 (RTD2553VH) #85~#94 output 8 bit odd LVDS digital data to panel control circuit through
CN105.
- U102(RTD2120) #44 outputs Brightness "PWM" signals to control CCFL brightness.
- U102(RTD2120) #39 output PPWR "H" potential to make Q114 conducted, and then make Q112
conducted, +5V flow to CN105#1~#3 as Panel VDD .
- U102(RTD2120) #46 output CCFL_ON/OFF "L" or "H" potential to control Inverter on/off.
- TCLK by Crystal 24MHz input to U102(RTD2120) #15,#16.
Please refer to RTD2120 Pin Assignments table in page.
3.2.4 Regulator Circuit
- +5V is from switching mode power supply for Panel used.
- +3.3V generates from +5V through C102 and C104 filtering and U101 which is output +3.3V LDO
for U102&U103 and U105 used.
- +1.8V generates from 3.3V through C101 and C103 filtering and Q106&Q107 which is output
+1.8V, for U103 used.
3.2.5 Audio circuit
- Audio Signal R,L,GND input through P701,#2,#5,#1, Stop DC via C704, C706, and then enter into
U701 (TDA8496L) analog input terminal #5,#1.
- U701 (TDA8496L) #14,#12 output R,L audio data to Speaker through CN701.
- U102(RTD2120) #47 output MUTE "H" potential to control U701on/off.
- U102(RTD2120) #45 outputs Volume "PWM" signals to control U701 Volume.

4. Inverter circuit

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Service Manual