EPSON PC500 Service Manual

EPSON

EPSON PhotoPC 500

SERVICE MANUAL

DIGITAL CAMERA

SEIKO EPSON CORPORATION

Rev.A

4006988

NOTICE

All rights reserved. Reproduction of any part of this manual in any form whatsoever

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without SEIKO EPSON’s express written permission is forbidden.

The contents of this manual are subjects to change without notice.

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All efforts have been made to ensure the accuracy of the contents of this manual.

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However, should any errors be detected, SEIKO EPSON would greatly appreciate
being informed of them.

The above notwithstanding SEIKO EPSON can assume no responsibility for any

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errors in this manual or the consequences thereof.

Epson is a registered trademark of Seiko Epson Corporation.

General Notice:

Other product names used herein are for identification purposes only and may be
trademarks or registered trademarks of their respective companies.

Copyright  1996 by SEIKO EPSON CORPORATION
Nagano, Japan

ii

PRECAUTIONS

Precautionary notations throughout the text are categorized relative to 1) personal injury and 2)
damage to equipment.

DANGER

WARNING

The precautioary measures itemized below should always be observed when performing
repair/maintenance procedures.

Signals a precaution which, if ignored, could res ult in ser ious or f atal per sonal injury.
Great caution should be exercised in perfor ming procedures pr eceded by DANGER
Headings.
Signals a precaution which, if ignored, could result in damage to equipment.

DANGER

1. ALWAYS DISCONNECT THE PRODUCT FROM BOTH THE POWER SOURCE AND
PERPHERAL DEVICES PERFORMING ANY MAINTENANCE OR REPAIR PROCEDURES.

2. NO WORK SHOULD BE PERFORMED ON THE UNIT BY PERSONS UNFAMILIER WITH
BASIC SAFETY MEASURES AS DICTATED FOR ALL ELECTRONICS TECHNICIANS IN
THEIR LINE OF WORK.

3. WHEN PERFORMING T ESTING AS DICTAED W ITHIN T HIS MANUAL. DO NOT CONNECT
THE UNIT TO A POW ER SOURCE UNTIL INSTRUCTED TO DO SO. W HEN THE POW ER
SUPPLY CABLE MUST BE CONNECTED, USE EXTREME CAUTION IN WORKING ON
POWER SUPPLY AND OTHER ELECTRONIC COMPONENTS.

WARNING

1. REPAIRS ON EPSON PRODUCT SHOULD BE PERFORMED O NLY BY EPSON CERTIFIED
REPAIR TECHNICIAN.

2. MAKE CERTAIN THAT T HE SOURCE VOLT AGE IS THE SAME AS T HE RATED VOLT AGE,
LISTED ON THE SERIAL NUMBER/RATING PLATE. IF THE EPSON PRODUCT HAS A
PRIMARY AC RATING DIFFERENT FROM AVAILABLE POWER SOURCE, DO NOT
CONNECT IT TO THE POWER SOURCE.

3. ALWAYS VERIFY THAT T HE EPSON PRODUCT HAS BEEN DISCONNECT ED FROM THE
POWER SOURCE BEFORE REMOVING OR REPLACING PRINTED CIRCUIT BOARDS
AND/OR INDIVIDUAL CHIPS.

4. IN ORDER TO PROTECT SENSIT IVEMICROPROC ESSORS AND CIRCUIT RY, USE STAT IC
DISCHARGE EQUIPMENT, SUCH AS ANTI-ST ATIC WRIST ST RAPS, WHEN ACCESSING
INTERNAL COMPONENTS.

5. REPLACE MALFUCNTIONING COMPONENTS ONLY WITH THOSE COMPONENTS BY
THE MANUFACTURE; INTRODUCTION OF SECOND-SOURCE ICs OR OTHER
NONAPPROVED COMPONENTS MAY DAMAGE THE PRODUCT AND VOID ANY
APPLICABLE EPSON WARRANTY.

iii

REVISION STATUS

Revision Issued Data Contents

Rev A October 29,1996 1st issued

EPSON OVERSEAS MARKETING LOCATIONS

EPSON America, Inc

20770 Madrona Avenue,
P.O. Box 2842
Torrance, CA 90509-2842
Phone: [phone]
Fax: [phone]

EPSON UK LTD.

Campus 100, Maylands Avenue,
Hemel Hempstead, Herts, HP2 7TJ
U.K.
Phone: [phone]
Fax: [phone]

EPSON IBERICA, S.A.

Avda. de Roma, 18-26
08290 CERDANYOLA DEL VALLES
Balcerona, Spain
Phone: [phone]
Fax: [phone]

EPSON AUSTRALIA PTY. LIMITED

1/70 Gibbes Street,
Chatswood 2067 NSW
Australia
Phone: [phone]
Fax: [phone]

EPSON HONG KONG LTD.

20/F, Harbour Centre,
25 Harbour Road, Wanchai, HONG KONG

Phone: [phone]
Fax: [phone]

SEIKO EPSON CORPORATION
Imaging & Information Products Division

EPSON DEUTCHLAND GmBH

Zülpicher Straße 6, 4000 Düsseldorf 11
F.R. Germany

Phone: [phone]
Fax: [phone]

EPSON FRANCE S.A.

68 bis, rue Marjolin 92300,
Levallois-Perret
France
Phone: [phone]
Fax: [phone]

EPSON ITALIA S.p.A.

V. le F. lli Casiraghi, 427
20099 Sesto S. Giovanni (MI)
Italy
Phone: [phone]
Fax: [phone]

EPSON SINGAPORE PTE. LTD.

NO.1 Raffles Place #26-00
OUB Centre
Singapore 0104
Phone: [phone]
Fax: [phone]

EPSON TAIWAN TECHNOLOGY &
TRADING LTD.

10F, No. 287 Nonking E. Road, Sec. 3,
Taipei, Taiwan, R.O.C.
Phone: [phone]
Fax: [phone]

80 Harashinden, Hirooka, Shiojiri-Shi, Nagano-Ken 399-07 JAPAN
Phone: [phone]
Fax: [phone]

iv

As of July, 1996

v

HAPTER

C

1. P

RODUCT DESCRIPTION

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...............................................................................................................1.2. Specifiation2

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..........................................................................................................1.2.2. Environmental conditions4

...............................................................................................................1.2.3. Electrical Specification4

..........................................................................................................1.2.4. Safety Standards and EMI4

.....................................................................................................................................1.2.5. Reliability5

.................................................................................................................1.2.6. Operating Conditions5

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....................................................................................................................................1.4.2. LCD Panel9

...............................................................................................................................1.4.3. LED Indicator10

......................................................................................................1.4.4. Buttons on the LCD monitor11

.......................................................................................................................1.4.5. Functional Setting12

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1.2.1. General specification2

1.3. Interface Specification5

1.3.1. Cable Specification6

1.4. Camera Operation8

1.5. Main Component13

1.1. Features1

1.4.1. Control buttons8

.1.

.2. Features

PhotoPC 500 is the digital still camera that has high image quality but inexpensive for its high
performance.
The major camera features are;

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* The Table 1-1 shows printable photos with optional memories and the figure below shows exterior view
of PhotoPC 500.

High Image Quality

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VGA (640 x 480 pixels, 24bit color)
Sensor

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Color Area CCD (Progressive Scan type)
Focus

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Fixed
Exposure

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Automatic
Internal memory

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2MB (for image and firmware)
Built-in-Flash

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4 mode : Auto/No-red eyes Auto/Off/Forced flash
Power

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AA-size batteries (Alkaline/Ni-Cadium/Lithium)
Size

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20% Smaller than CP-100
Interface

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High Speed Serial interface : 19200bps (min.)1 15.2Kbps (max.)
Option

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Expand Memory 2/4MB (See Table 1-1)

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AC adapter

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LCD monitor
Camera control is available from the PC.
Various filters and lenses for 37mm video camera can be attached to the front lens.

Table 1-1. Optional Units

Unit Model No.

Expansion Memory module (2MB) B808201

Expansion Memory module (4MB) B808211

Figure 1-1. Exterior of PhotoPC 500

PHOTOPC 500 SERVICE MANUAL Service Manual

.3. Specifiation

This section describes detailed specifications of the camera.

1.

[ Recorded Image]

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High resolution 30 65 100
Standard resolution 60 130 200

General specification

Internal memory : 2MB (including approx.300KB Program Area)
Expandable Memory : Expandable Memory Module 2MB/4MB(Same as CP-100)
Compression : JPEG
File Format : JPEG. Including thumbnail (H80xV64 pixels), Date and time

information

Resolution : High resolution 640 x 480 pixels

: Standard resolution 320 x 240 pixels
White Balance : Automatic adjustment
Sensitivity : ISO 130 equivalent
Color : 24bit Full Color (8bit pixel x3)
Processing Time : High resolution Approx. 6 sec

Standard resolution Approx. 2 sec

* Red LED on side of viewfinder will flash during processing.
Number of images with Expandable Memory Module (see below Table 1-2)

Table 1-2. Printable photos with memory

Default +2MB +4MB

[CCD]

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[Lens]

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[Viewfinder]

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[Shutter]

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While connecting to PC, you can adjust from Application. But it
returns to Automatic mode after disconnecting from PC.

[Iris]

Feature : 1/3» ICX084AK (SONY) Square pixel
Total Pixels : 692(H) x 504(V) Approx. 350K pixels
Available Pixels : 659(H) x 494(V) Approx. 330K pixels
Transfer : Progressive scan type

Focus Distance : 6mm equivalent to 43mm lens on a 35mm camera
Aperture Ratio : 1:2.8
Focus range : 60cm infinity (Flash available by 3.0m)

20cm infinity (available with LCD monitor)
Structure : 5 set 5 pieces

Type : Optical Virtual Image
Magnification : x0.65
Indicator in Viewfinder : Guide Frame

Method : Electronic shutter
Exposure : Automatic 1/30 1/10000 sec.

2

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3

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Method

is

[Exposure Control]

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Method : Exposure control by iris-Shutter change program (Automatic)

[Measurement]

Chapter 1 Product Description

:

Fixed mechanical iris F2.8/F8 (When the optional LCD monitor

installed, F8 is fixed at close distance photo mode)

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Method : Center-prioritized light measurement
Sensor : As both for CCD image capturing sensor

[Built-in Flash]

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Type : Fixed Built-in Flash
Mode : Auto/ No red-eyes Auto/Off/Forced flash

Exposure Control Method : Automatic Luminance Control by Pre-flash
Color temperature : 5500K degree
Distance : 0.45m3m
Guide number : G No 8.4 (ISO100 Equivalent) G No 9.6 (ISO130 Equivalent)

[Self-Timer]

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Time : 10 sec. (cancelable by pushing timer switch)

[Power]

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Main power supply : AA Alkaline x 4 or

Battery Life : > 200 pictures (without LCD monitor, 50% flash, Alkaline
AC adapter : Optional

: Auto/ No red-eyes Auto:Auto flashing against low brightness and

backlight

AA Ni-cd x 4 or
AA Ni- MH x 4 or
AA Lithium x4
* Mixing different type of batteries are not acceptable.
* Can not charge Ni-Cd or Ni-MH by camera.
* Battery life indicator is useful only on Alkaline Battery.

Battery)

[External interface]

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DC input : NewEIAJ Type3, 5.5mm diameter, center plus
Output : RS232C, Mini Din 8pin
LCD monitor adapter terminal : yes

[Date/Time]

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Recording Method : Digital data recorded in file

(year/month/day/time/minute/second)

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Date/Time Setting : Only adjustable from PC
Back up : Date and Time will be cleared when batteries are dead or

after the batteries are replaced exchanging.

[Erase]

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All Erase : Camera: Erase+Selftimer button

PC : From Application

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Erase one image : Camera: Erase for last image

LCD Monitor attached allows to erase selected one.
PC : Selected image erasable from Application

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Erase Time : All erase <10 sec. (When no Expand Memory)

Erase one image < 0.5 sec.

Rev. A

PHOTOPC 500 SERVICE MANUAL Service Manual

4

[Sound]

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[Auto Shut Off]

PhotoPC 500 goes to Power Save mode under following conditions.

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Camera only : Default 1min (Adjustable from PC Application)
Connecting with PC : Default 5min (Not adjustable)
Using AC adapter : No power saving

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[Others]

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Beep sound : After picture is taken and during image processing. (Once:pi)

Error beep sound occur when pushing shutter during image

processing. (Twice:pipi)

Without LCD Monitor

With LCD Monitor
View Mode : Camera On as same as camera only

Camera Off Turn Off 10 sec. after warming sign
Playback Mode : Default 5min (Not adjustable)
To return from Power saving : Push the Shutter button

Screw for tripod : Yes
37mm thread for additional lens or filter available

[Exterior]

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2.

[Acceptable environment]

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3.

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Max.: DC 8V

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4.

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EN61000-3-3,
EN55082-1
IEC801-2

Dimensions : 141.2 (W) x 81 (H) x 52.6 (D) mm (Camera only)

221.5 mm x 81mm x 60.6 mm ( With the optional LCD monitor )

Weight : Under 300g (Without batteries, without LCD monitor)

Environmental conditions

Temperature Operating : 0 to 40 degree

Storage : -20 to 60 degree

Humidity Operating : 30 to 90% no condensation

Storage : 10t o 90% no condensation

Electrical Specification

Requirement of supply voltage for DC input (AC adapter)

Min.: DC 6.3V

Absolute maximum supply voltage for DC input

Max.: DC 10V

Safety Standards and EMI

USA : FC Class B
Europe : EN55022 Class B,

EN61000-3-2,

IEC801-3
IEC801-4

Rev. A

Chapter 1 Product Description

5.

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6.

Place : Ordinary home, office or outside

Reliability

FLASH memory life : 10K cycle write for FLASH memory

Operating Conditions

.4. Interface Specification

PhotoPC 500 can be connected to the PC only by the serial interface(RS-232C compatible).
The minimum s peed requirem ent of serial inter fac e of PC is 19200bps . T his sec tion descr ibes the use of
serial interface and cable.

[Serial Interface]

Data format: RS-232C
Communication method: Asynchronous. 8bit, Non Parity
Speed: 19200,38400,57600,115200 bps

Rev. A

5

PHOTOPC 500 SERVICE MANUAL Service Manual

6

1.

This section describes DOS/V connector cable and conversion connector for Mac.

3

[Cable/connector description 1: DOS/V Cable]

The following figure shows the connection diagram of DOS/V cable.

Cable Specification

7

6

4

8

5

2

1

Figure 1-2. Cable for PC

1
2

3

4
5

6
7
8
9

Figure 1-3. Connection for diagram for DOC/V cable

Rev. A

[Cable/Connector description 2: MAC adapter]

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6

4

3

8

5

2

1

Figure 1-4. Mac adapter

Chapter 1 Product Description

1
2

3

4
5

6
7
8
9

The following figure shows the connection diagram of MAC Cable.

Figure 1-5. Connection for Mac cable

Rev. A

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PHOTOPC 500 SERVICE MANUAL Service Manual

8

.5. Camera Operation

This section describes LCD panel display and its functions.

1.

The LCD panel consist of 5 buttons and displays the camera operation. The power s witch is loc ated under
the lens and move along with the closing and opening movement of shutter. The following Figure1-6
shows
these 5 buttons on the LCD Panel and their functions.

Control buttons

Figure 1-6. Control buttons

Button A

*

Button B:

*

Button C:

*

Button D:

*

Button E:

*

: Shutter Button. Photo shooting.

Erase button. Function is different according to the following conditions.
*Without LCD monitor : erase last image
* With LCD monitor :

Playback mode : erase displayed image
Off or View mode : erase last image

*All images erase : push Self-Timer button while pressing Erase button
Flash mode button. Flash mode will be changing cyclically as following;

AutoNo red-eyes autoOffForced flashAuto
Resolution button. Change resolution alternatively between High resolution and

Standard resolution.
Self-timer button. When pushing, Self-timer indicator will flash. Under this condition

picture will be taken after 10 seconds from pushing shutter.

Rev. A

Chapter 1 Product Description

9

2.

The camera operation mode is displayed on the LCD. The following figure 1-7 shows its exterior and
its 8 displays.

Display A :

LCD Panel

Figure 1-7. LCD Panel

The number of pictures taken is indicated. If the camera is controlled by the PC,
the frame around the numbers flashes.

Display B :

S: Standard Resolution
Hi: High Resolution

Display C :

Display D:
Display E:

will flash and then turn off the power.

Display F:

Display G:
Display H:

communication with PC.

The present resolution type is indicated.

Erase indicator. This indicator flashes while the camera is deleting a picture.
Self-timer indicator. Indicator will flash when selftimer enable.

Battery life indicator. This indicates the 7 battery levels. When empty, indicator

Flash mode. Auto/No red-eyes auto/Forced flash/ Off. Refer to the
following figure. (See figure 1-8.)

Number of pictures remaining. This depends on the resolution setting you have chosen.
Connecting to PC. Line around the number of pictures taken will flash under
Line under the number of pictures taken will appear when cable is connected to

PhotoPC 500.

Rev. A

PHOTOPC 500 SERVICE MANUAL Service Manual

0

Auto

3.

PhotoPC 500 has two indicators located on beside viewfinder and one on the left side above
of lens. The followings describe the location of indicators and description of these indicators.

LED Indicator

No red-eyes auto

Figure 1-8. Flash mode

Forced flash

Off

Figure 1-9. LED indicator

Indicator A:

*Red LED Red flashing: Photo shooting not available under following

conditions;
Image Processing/ Changing Flash/ Processing after Power ON

Red light : Full memory

Indicator B:
*

Stand -by Green LED Green light : Photo shooting available

Indicator C:

*Selftimer LED (red) After you set the self-timer;

0-7sec. light7-10 sec.flashing10 sec. Photo shooting

1

Rev. A

Chapter 1 Product Description

4.

[Type]

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Buttons on the LCD monitor

Size/LCD 1.8» TFT Color LCD
Of Pixels 61,000pixels H279 x V220

Power/Mode switch

Figure 1-10. Exterior view of LCD monitor

+ button

- button

MACRO button

MULTI button

[View (Recording) Mode]

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[Playback Mode]

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Monitor Display image from CCD in real time, display ratio: 1/30 sec.

Freezing image during processing

Brightness Adjustable with ‘+,-’ switch in only VIEW mode

Display level of brightness in adjustment (disappear in 3 sec.)

On-Screen Display Brightness level in VIEW mode

Macro mode
Close-up Function Macro switch (from 0.45cm)
Other If switch is set to VIEW mode under Power OFF, display warning message

in 10 sec. and then LCD power goes to OFF.

Playback Display Default: Full screen display for last picture

Selectable with ‘+,-’
On-Screen Display Image Number (disappear in 10 sec.)

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PHOTOPC 500 SERVICE MANUAL Service Manual

No image icon

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[ERASE]

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* After erasing, image number will be renumbered.

Slide Show 4sec./image

Start slide show by keep pushing ‘+’
Recycling all images
(Power save will be effective after one cycle of slide show)

Multi-Screen Multi-Screen in playback mode 9 image on screen using

thumbnail data

Other When PLAYBACK mode, control panel shows «LCD».

Even if camera’s Power switch is OFF, the camera can go to
PLAYBACK mode.

When LCD monitor is;

OFF : Erase last image by pushing Erase button
VIEW mode : Erase last image by pushing Erase button
PLAYBACK mode : Erase displayed image by pushing Erase button

(e.g. if #10 image erased, #11 will become #10 image)

[When connecting to PC]
[Button on LCD monitor]

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5.

PhotoPC 500 has 2 methods in order to set or change the various functions ; either by the method
directly from the body or by using utility soft from the PC.
The following describes functions that can be set from the camera body or from the PC.

Power/mode switch OFF : LCD monitor power OFF

+button VIEW mode : Brightness control of LCD monitor

-button VIEW mode : Brightness control of LCD monitor
MACRO button Change mode alternately between MACRO recording mode

MULTI button Change mode alternately between 9 image display mode

Functional Setting

LCD monitor will be OFF, when connecting to PC.

(See figure1-10)

VIEW :VIEW mode
PLAYBACK :PLAYBACK mode

PLAYBACK mode: display next image
PLAYBACK mode: display previous image
and Normal recording mode.

This button is effective only VIEW mode.
Power ON default is Normal mode.

and Normal display mode.
This button is effective only PLAYBACK mode.
Power ON default is Normal mode.

[Available functions from the body]

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[Available functions from the PC]

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Resolution : Available either High Resolution or Standard Resolution
Flash : auto/forced flash/off by one button
Self-timer : On/Off
Shooting : Available
Power : On/Off
Erase one image : Erase for the last image
Erase all images : Erase button + Self timer button

Shutter speed : Available among Auto,1/30, 1/60, 1/125, 1/250, 1/1000.1/2000,

1/4000,1/10000 sec.
* In case of Auto, range will be set automatically from 1/30 to 1/10000.

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Chapter 1 Product Description

3

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* When you down load the taken image data to the PC from the camera, the LCD on the camera indicate
« Low battery». Although this status appears even when the new batteries are installed, it is inevitable
phenomenon since it is done by voltage from battery detection.

Resolution : Available either High Resolution or Standard Resolution
Flash : auto/ forced flash/ off by one button
Self-timer : On/Off
Erase : Erase for the last image. Erase button + Self timer button erase all

images.

Date/Time : Set the same time as PC has. Available

year/month/date/time/second

setting.
Continuos image transfer
Communication speed 19200/38400/57600/115200 bps (This speed varies according to

the PC, O/S and application software.)

.6. Main Component

The followings are the main component of PhotoPC 500. Please refer to Chapter 2 for its location
and function.

1) SY1 Board 4) CA2 Board 7) Camera mechanism

2) CA1 Board 5) PW1 Board 8) TB2 Board

3) TB1 Board 6) ST1 Board 9) Housing

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C

2. O

PERATING PRINCIPLES

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............................................................................... 2.1.1.1. IC Function on CA1 Board2

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......................................................................................................................2.1.3. Circuit Description11

.............................................................................................................2.1.4. PW1 Circuit Description12

..............................................................................................................2.1.5. SY1 Circuit Description13

............................................................................ 2.1.5.1. Internal Communication Bus14

.................................................................................................... 2.1.5.2. Power Supply Control14

..........................................................................................

............................................................................................. 2.1.6.1. Charging Circuit15

.................................................................................................... 2.1.6.2. Light Emission Circuit16

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2.1. Operating Principles1

2.1.1. CA1 Circuit Description2

2.1.2. Outline of Operation11

2.1.6. ST1 Circuit Description15

2.1.7. LCD Block16

.1.

.2. Operating Principles

This section desc ribes operation principle of c amera. Since the PhotoPC 500 is s till digital camera, there
is no complicated mechanism and most of the operation is done by the control of electric circuit. The
figure below explains location of each major electric circuit.

TB2 board

SY1 board

CA1 board

TB1 board

PW1 board

ST1 board

Figure 2- 1. PhotoPC 500 Board Location

PhotoPC 500 Service Manual

1.

CA1 Circuit Description

The followings explain operating features on the CA1 board.

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Independent storage and retrieval for each pixel

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Square pixel unit cell

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VGA compatible

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R,G,B primary color mosaic filter

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Continues variable speed electric shutter function

1.

IC Function on CA1 Board

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IC903 (ICX084AK) CCD imager

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IC902 (MC74HC04) H driver

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IC904 (CXD1267AN) V driver

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IC905 (CXA1690Q) CDS/AGC

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IC906 (CXD2311AR) A/D converter

[1. IC903 (CCD)]

**Structure**

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Interline type CCD image sensor

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Optical size 1/3 inch

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Effective pixels 659(H) x 494(V)

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Pixels in total 692(H) x 504(V)

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Chip size 5.84mm (H) x 4.94mm (V)

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Unit cell size 7.4m(H) x 7.4 (V)

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Optical black Horizontal (H) direction:

Front 2pixels, Rear 2pixels1
Vertical(V) direction:
Front 8pixels, Rear 2pixels

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Dummy bit number Horizontal: 16

Vertical : 5

2

V

Pin 9

Pin 1

H

2

8

31

Figure 2- 3. Optional Black

Location

Note:

Photo sensor

Figure 2- 2. CCD Block Diagram

2

Rev. A

3

The following shows CCD Pin Description (IC903).

Chapter 2 Operating Principles

Figure 2- 4. IC903(CCD) Pin Description

Rev. A

PhotoPC 500 Service Manual

4

[2. H-Driver (IC902) and V-Driver (IC904)]

An H driver (IC902) and V driver (IC904) are necessary in order to generate the clocks (vertical transfer
clock, horizontal transfer clock and electronic shutter clock) which drive the CCD.
IC902 is an inverter IC which drives the horizontal CCDs(H1 and H2). In addition the XV1-XV3 signals
which are output from Pins(39)-(41) of IC102 on the CA2 circuit board are the vertical transfer clocks, and
the XSG signal which is output from Pin(43) of IC102 is superimposed onto XV2 and XV3 at IC904 in
order to generate a ternary pulse. In addition, the XSUB signal which is output from Pin(42) of IC102 is
used as the sweep pulse for the electronic shutter, and the RG signal which is output from Pin(38) of
IC102 is the reset gate clock.

Figure 2- 5. IC902 Block Diagram

Figure 2- 6. IC904 Block Diagram

Rev. A

Chapter 2 Operating Principles

[3.IC905 (CDS/AGC Circuit)]

The video which is output from the CCD is input to Pins (25) and (26) of IC905. There are S/H blocks
inside IC905. There are S/H blocks inside IC905 generated from the XSHP and XSHD pulses, and it is
here that CDS (correlated double sampling) is carried out.
After passing through the CDS circuit, the signals pass through the AGC amplifier, LPF (low-pass
filter), S/H, blanking processing circuit, driver and clamper, after which they are sent to IC906.
The PWM voltage at Pin(18) is output from Pin(65) of IC102 and passes through the AND buffer of
IC907, after which it is smoothed, and this voltage controls the AGC amplifier gain.

Figure 2- 7. IC905 Block Diagram

[4. IC906 (A/D Converter)]

The video signal which is output from Pin(7) of IC905 and input to Pin(39) of IC906 is A/D-converted
to 10-bit signals inside this IC, and are then input to IC102.
A/D conversion is synchronized with the clock at Pin(22), and the reference voltages VRT(approximately

4.0V) and VRB(approximately 2.0V) are supplied from IC905.

Rev. A

Figure 2- 8. IC906 Block Diagram

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PhotoPC 500 Service Manual

6

[5. Vertical Transfer Operation of the V Register]

The V register has three different electrodes which are designated as V1, V2 and V3. In step , the
potential at V2 is high and the potentials at V1 and 3 are low, so that there is a well at V2 for the
signal’s electric charge. In step , the potential at V1 becomes high, and so the well becomes wider
to include both V1 and V2. In step , the potential at V2 becomes low, causing the charge to accumulate
in the well at V1.The charge has thus been transferred by one electrode compared to the condition in
step . The condition at step represents a transfer of one pixel from the condition in step .

Direction of
transfer

V3 V2

1

V1

V3

V3

V2

V1V2

2

1

V1

V2

V3

4

3

5

6

7

Figure 2- 10. V1,V2 and V3

During the Horizontal Blanking

Period

2

3

4

5

6

7

Figure 2- 9. 3-Phase Drive Model Chart

Rev. A

Chapter 2 Operating Principles

[6. V Register Read Operation from Photo Sensor]

This system employs the 3-value drive V register as shown in figure2-11.
During transfer of the V register, the applied voltage at the V register electrode is low. Therefore, the
electric charge for the signal cannot be output from the photo sensor section. However, since the
applied voltage during reading becomes high, the electric charge for the signal is transferred to the
V register.

Applied voltage

During transfer

During read
operation

V register(during transfer)

V3

V2

V1

V3

V2

V1

Direction of transfer

V register electrode

Light beam

Sensor electrode

Signal electric
charge

When reading P-Si

Photo sensor
section

During read
operation

A more detailed explanation is given below.
The transfer operation from the photo sensor
section to the V register is shown in Figure 2-12.
In Figure 2-12, V1 to V3 change as shown in
to . When V1(to V3) is -7.5V, the potential of the
V register becomes a barrier, and it becomes a
well when they are 0V. The potentials of V2 and
V3 and that of the sensor gate become the lowest
well under the condition at. Thus the signal
electric charges from the sensor section move to
V2 and V3 respectively, and are transferred as
shown in to.

Rev. A

Figure 2- 11. Read Out by 3-Value Drive

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PhotoPC 500 Service Manual

8

[7. Transfer of
Electric Charge by V
Register]

The H register sets H2
to a low potential
during H blanking, and
switches to a state of
waiting for a signal
from the V regis ter, as
shown in figure 2-13.
On the other hand,
during H blanking, the
V register

Light receiving section

V register

-7.5V
+15V

-7.5V

+15V

-7.5V

0V

0V

0V

which stopped during
the H scanning period
after switching V2 to

Figure 2- 12. Read Timing at the Sensor Section

low potential makes a
transfer
operation for one line based on 3-phase drive as shown by to in the figure.

Shaded section : Well
Other : Barrier

(Potential variations of H register during
the hrozontal blanking period.)

Figure 2- 13. Ve rtical Transfer of CCD and Application of Electric Charge

to the H Register

Because the H1 potential is lower than
the V2 potential, electric charges move
to H1 of the register.

Rev. A

Chapter 2 Operating Principles

9

[8. Transfer of Electric Charge by the H Register]

The transfer system for the horizontal CCD employs a 2-phase drive method.
The electric charges sent to the final stage of the horizontal CCD are transferred to the floating
diffusion, as shown in figure 2-14. RG is turned on by the timing (1), and the floating diffusion is charged
to the potential of PD. The RG is turned off by the timing in (2). In this condition, the floating diffusion is
floated at high impedance.
The H1 potential becomes shallow by the timing in (3), and the electric charge now moves to the
floating diffusion.
Here, the electric charges are converted into voltages at the rate of V=Q/C by the equivalent capacitance
C. RG is then turned on again by the timing in (1) when the H1 potential becomes deep.
Thus, the potential of the floating diffusion charges in proportion to the quantity of transferred electric
charge, and becomes CCD output after being received by the source follower. The equivalent circuit
for the output circuit is shown in figure 2-15.

H1

H2

H2 H1

H1

H1

H1

H2

H1

H2

H2

H1

H1

H1

H2

HOG

HOG

HOG

RG

RG

RG

PD

PD

CCD OUT

CCD OUT

H1

H2

RG

CCD OUT

(1) (2) (3)

5V
0V

5V
0V

5V

0V

RG pulse leak signal

Signal voltage

Black level

Figure 2- 14. Horizontal Transfer of CCD Imager and Extraction of Signal Voltage

Rev. A

PhotoPC 500 Service Manual

0

Reset gate
pulse

Direction of transfer

H Register

Electric
charge

Floating diffusion gate is
floated at a high impedance.

C is charged
equivalently

+B 15V Pre-charge
drain bias (PD)

Figure 2- 15. Theory of Signal Extraction

Operation

Voltage output

[9. Vertical Overflow Drain (VOFD)]

The CCD of this system is configured as shown in Figure 2-16. An imager which has OFD(SUB) provided
in the vertical direction(in the direction of depth) of a CCD chip is referred to as a CCD with a vertical
overflow drain (VOFD) construction. When the potential along the dotted line(A-A’) is seen from (a), it
appears as (b). The height of the potential barrier is decided by applying DC bias to the OFD from
outside.
This is the same as deterring the saturated electric amount Qs (equals the dynamic range) at the sensor.
Although a larger Qs is preferable, a Qs which is too large causes blooming (a phenomenon where the
electric charge becomes too large and leaks into other picture elements), which causes the picture

quality to deteriorate. Therefore, it is necessary to

V register

CS

A

ROG

Sensor

CS

apply a well-balanced DC bias.

[10. Electric Shutter]

During normal operations, read-out of the signal
charge can be made once for each field. Thus, the
storage time for the electric charge is 1/30 sec.

(a)

N-Si

A'

SUB(OFD)

However, the actual storage time can be shortened
by throwing away the electric charge during storage.
(Refer to figure2-17.) The electric shutter needs
this kind of electric charge throwaway operation.
The electric charge throw-away operation necessar y
for the electronic shutter in this system is controlled

V register

Sensor

SUB(OFD)

by the DC bias applied to the SUB.
Actually, the throwaway operation is done during the
horizontal blanking period in order to keep the
picture free from any noise that may appear. Under

(b)

Qs

VSUB=V1

normal conditions, the DC bias of the SUB is
overlapped by pulse. (Refer to figure2-18.)
In theory, it is possible to use the above system
to control an electric shutter with a storage time of

VSUB=V2

1/30 sec to 1/10000 sec, in units of 1/15750.

VSUB=V3

V1<V2<V3

Figure 2- 16. VOFD and Potential Chart

1

Rev. A