KAI-4021 datasheet(11/56 Pages) ONSEMI

11 / 56 page

KAI-4021 Image Sensor

www.truesenseimaging.com

Revision 1.1 PS-0014 Pg 11

HORIZONTAL REGISTER TO FLOATING DIFFUSION

Figure 4: Horizontal Register to Floating Diffusion Architecture

The HCCD has a total of 2124 pixels. The 2112 vertical shift registers (columns) are shifted into the center 2112 pixels

of the HCCD. There are 12 pixels at both ends of the HCCD, which receive no charge from a vertical shift register. The

first 12 clock cycles of the HCCD will be empty pixels (containing no electrons). The next 28 clock cycles will contain

only electrons generated by dark current in the VCCD and photodiodes. The next 2056 clock cycles will contain photo-

electrons (image data). Finally, the last 28 clock cycles will contain only electrons generated by dark current in the

VCCD and photodiodes. Of the 28 dark columns, the first and last dark columns should not be used for determining the

zero signal level. Some light does leak into the first and last dark columns. Only use the center 26 columns of the 28

column dark reference.

When the HCCD is shifting valid image data, the timing inputs to the electronic shutter (SUB), VCCD (V1, V2), and fast

line dump (FD) should be not be pulsed. This prevents unwanted noise from being introduced. The HCCD is a type of

charge coupled device known as a pseudo-two phase CCD. This type of CCD has the ability to shift charge in two

directions. This allows the entire image to be shifted out to the video L output, or to the video R output (left/right

image reversal). The HCCD is split into two equal halves of 1068 pixels each. When operating the sensor in single

output mode the two halves of the HCCD are shifted in the same direction. When operating the sensor in dual output

mode the two halves of the HCCD are shifted in opposite directions. The direction of charge transfer in each half is

controlled by the H1BL, H2BL, H1BR, and H2BR timing inputs.

H2S

H1S

H1B

H2S

H2B

H1S

Floating

Diffusion

n (burried channel)

p (GND)

n (SUB)

H2B

KAI-4021 Datasheet(PDF) 11 Page - ON Semiconductor