LiteOn B17AAU, Руководство по обслуживанию, Страница: 4 / 31

Page 1 Circuit Description
B17AAU / B17ANU / B17AAY
1. Audio circuit (Circuit diagrams Main PWB) KT
1.1 Audio input
The audio signal input received from the audio input terminal (P311) is applied to the amplifier I332 of 4 (L-CH)
and 9 (R-CH) through the low-pass filter consisting of R408, R410, R409, R407, C598 and C599.
In this amplifier, controls of Volume, and mute are conducted. The audio signal controlled at the pin 6 deter-
mines the attenuation of output of the amplifiers. Since then, the signal is output to the jack P312.
1.2 Audio output
The audio signal is output from the jack output terminal (P312) of the jack board to the internal speaker system.
2. Power supply (Circuit daigrams MAIN PWB 6/8, 7/8)
2.1 P310 connector
A 5V power supply for LCD module, CPU, and logic is generated from the P310 connector.
2.2 I323:3-terminal regulator
A 3.3V power supply for Scaler IC I315, LVDS IC I319, I320 is generated from the 5V source.
2.3 I324:3-terminal regulator
A 2.5V power supply for Scaler IC I315 is generated from the 5V source.
Q307, I321 ON/OFF control for LCD Module
ON/OFF control is performed for power ON/OFF and also for the power saving sequence.
3. Video input circuit (Circuit diagram MAIN PWB 3/8)
The analog video signal input entered from P304, the AC-coupled video signal is used to clamp the black level at
0V).
4. Definition converter LSI peripheral circuit (Circuit diagram MAIN PWB)
I315 gm5020 is the definition converter LSI.
The analog R, G, B signal input entered from the video input circuit is converted into the digital data of video
signal through the incorporated A/D converter. Based on this conversion, this device performs interpolation
during pixel extension. The source voltage for this device is 3.3V, 2.5V and the system clock frequency is
24MHz. The withstand voltage level for the input signal voltage if I315 is 3.3V and 5V.
5. System reset, LED control circuit (Circuit diagram MAIN PWB 2/8)
5.1 System reset
System reset is performed by detecting the rising and falling of the 5V source voltage at I301.
5.2 LED control circuit
Green / amber is lit with the control signal of the LED GREEN and LED AMBER signal pin 25, 26 from I302
(Circuit diagram MAIN PWB 2/8).
6. E
2
PROM for PnP (Circuit diagram MAIN PWB 3/8)