TC211

192-

× 165-PIXEL CCD IMAGE SENSOR

SOCS008B – JANUARY 1990

2-2

POST OFFICE BOX 655303

functional block diagram

Serial Register

1

192

Clear Gate

165

12 Dark Pixels

192 Image Pixels

6 Dummy Pixels

ABG

ADB

OUT

VSS

1

3

4

2

6

5

1

IAG

SRG

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

ABG

1

I

Antiblooming gate

VSS

2

Amplifier ground

ADB

3

I

Supply voltage for amplifier drain bias

OUT

4

O

Output signal

SRG

5

I

Serial-register gate

IAG

6

I

Image-area gate storage

functional description

The image-sensing area consists of 165 horizontal image lines each containing 192 photosensitive elements

(pixels). Each pixel is 13.75

µm (horizontal) by 16.00 µm (vertical). As light enters the silicon in the

image-sensing area, free electrons are generated and collected in potential wells (see Figure 1). During this

time, the antiblooming gate is activated by applying a burst of pulses every horizontal blanking interval. This

prevents blooming caused by the spilling of charge from overexposed elements into neighboring elements. The

antiblooming gate is typically held at a midlevel voltage during readout. The quantity of charge collected in each

pixel is a linear function of the incident light and the exposure time. After exposure and under dark conditions,

the charge packets are transferred from the image area to the serial register at the rate of one image line per

each clock pulse applied to the image-area gate. Once an image line has been transferred into the serial register,

the serial-register gate can be clocked until all of the charge packets are moved out of the serial register to the

charge detection node at the amplifier input.

There are 12 dark pixels to the right of the 192 image pixels on each image line. These dark pixels are shielded

from incident light and the signal derived from them can be used to generate a dark reference for restoration

of the video black level on the next image line.