Toshiba TLP511E - Manual (Page 43)

8-1
8. CCD CAMERA CIRCUIT
(For TLP511)
8-1. Outline
The camera section of the unit employs the color board
camera with 3 times zoom lens. The camera video circuit
is assembled in one PC board and composed of the CCD
and drive circuit, pre-amp and AD converting circuit
(CDS, AGC and AD), video signal process circuit (DSP,
MICON) and power supply circuit.
Fig. 8-1-1 shows a block diagram of CCD camera circuit.
8-1-1. CCD and Drive Circuit
The CCD (Q101) circuit employs 1/3 inch 480,000 pixels
IT-CCD. The horizontal transmission pulse (H1, H2 and
RG) and vertical transmission pulse (øV1 – øV4 and
SUB) are supplied through the drive signal generation
circuit and vertical drive IC (Q103 and Q202) inside DSP
(Q203) by 28.5 MHz clock signal output from the
oscillator (Z201).
8-1-2. Pre-amp and AD Coversion Circuit
(CDS, AGC, AD)
The video signal developed from CCD (Q101) enters the
pre-amp IC (Q201) through the buffer (Q102).
After the signal is processed the noise reduction process
(CDS) inside the IC and amplified (AGC), the signal is
converted to AD, and then output as 10 bits digital data.
8-1-3. Video Signal Process Circuit
(DSP, MICON)
The video signal, which became 10 bits digital data,
enters the DSP (Q203) for video signal process. After the
signal is separated into the luminance and color signals,
the signal process is carried out on the luminance and
color signals respectively and DA-converted.
The luminance signal adds the sync signal and passes
through 7 MHz low pass filter. The color signal is
developed through the video driver IC (Q206) after
passing 4.43 MHz band pass filter.
All kinds of parameters on DSP (Q203) are set up by the
microprocessor (Q303) and picture quality adjustment,
etc. are carried out.
These parameters are memorized in the E 2 PROM
(Q306). Also, the zoom, focus, etc. controls of lens are
carried out by communicating with the external device
through RS-232C driver IC (Q304).
8-1-4. Power Supply Circuit
The power supply circuit generates DC voltages (+15V,
+5V, +3.3V, –8.2V) necessary to the camera signal
process and power supply voltage (+9V, +5V) for lens.
Lens +9V, develops the power supply voltage (+9V)
entered from outside directly and for lens +5V, input +9V
is developed through the regulator IC (Q801).
The signal process +5V develops the power supply
voltage (+5V) entered from outside directly and the
signal process +3.3V, the input +5V is developed through
the regulator IC (Q802). The DC voltage of +15V, –8.2V
are developed from the constant voltage circuit through
the change pump circuits of Q804 – Q806.