Sony DSC-D700 Service Manual page 102

A low-temperature polysilicon type of 180,000 pixels is used for the 2.5-inch liquid-
crystal display panel of this time so as to display a clear picture with horizontal
resolution of more than 400 lines. This liquid-crystal display panel and IF-717
board are connected through the flexible board by connector CN708. A drive signal
for the liquid-crystal display is produced by IC702 CXA2543R.
IC702 is a drive circuit exclusively used for color liquid-crystal display panel
DCX501. In IC702, the RGB decoder function of a video signal, a drive function,
and a panel drive timing pulse generator are put in one chip to reduce the number of
parts and circuits required for driving the liquid-crystal display panel. Moreover,
each mode setting or adjustment is directly controlled from the system
microcomputer using an internal serial interface circuit and electronic volume.
Major functions are described below.
1. Internal drive circuit for color liquid-crystal display panel DCX501
2. NTSC/PAL system compatible
3. Y/C input compatible
4. Internal serial interface circuit
5. Internal electronic volume (D/A converter)
6. Internal BPF, TRAP, and DL
7. Internal sharpness function
8. Internal two-point gamma correction circuit
Crystal oscillator X701 connected to pins 56 and 57 of IC702 generates a subcarrier
frequency. A crystal oscillator of 3.58 MHz is mounted for NTSC, and a crystal
oscillator of 4.43 MHz is mounted for PAL.
The trap frequency of a chroma signal is formed at pin 1 of IC702. The frequency is
changed for NTSC and PAL by connecting LC to the outside.
A system clock of IC702 is generated and input at pins 14 and 15 of IC702. The
input video sync signal is synchronized using an internal PLL circuit. A PLL circuit
is adjusted by controlling the potential of a D/A converter.
A chroma signal is input through Q725 to pin 59 of IC702 and a video Y signal
(described later) is input to pins 3 and 61 of IC702. At that time, a picture appears
on the liquid-crystal display panel.
Pins 33 to 35 of IC702 are used as the serial interface of IC702. Pin 33 to 35 are
connected to the system controller board via connector CN701 and used to set the
operating mode or adjustment value of IC702.
IC707 is a 10-channel D/A converter. Pins 14 to 17 of IC707 are used as a serial
interface. Pins 14 to 17 are connected to the system controller board via connector
CN701. A D/A output signal is changed from the system controller by
communication data to control the adjustment or on/off operation of each circuit.
The main items to be adjusted are a Y signal, a chroma signal level value, SIG CET,
BLNK, LIM, and PICTURE of a liquid-crystal display panel drive signal, a COM
voltage, and a PSIG signal. A PLL circuit is adjusted from this D/A converter.
(Refer to section 3 ELECTRICAL ALIGNMENT)
4-14 DSC-D700 (UC,CE)