Toshiba TLP511U CCD and Drive Circuit, Pre-amp and AD Coversion Circuit, Power Supply Circuit

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 E2PROM (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.

8-1