PixArt Imaging Inc.

PAS109B

CMOS Image Sensor IC

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3

PixArt Imaging Inc.

V1.1, Mar. 2002

2. Block Diagram

CS

PXCK

VSYNC

HSYNC

Reference

Voltage

Interface

control

D0..D7

b0..b9

Gain code

Time

Ex posure

Gen.

Clock

ADC

10- Bit

ReadOut

CDS +

Row drive

Column &

(164x124)

Imager

Control

Timing

Decision

AEC/AGC

PGA

Block Diagram

Control register

I2C

SCL

SDA

Edge detect

Data packing

Data companding

DAC 9-bit

Fig 2.1 – Block diagram of PAS109

As the block diagram of PAS109 is shown in Figure 1. By pulling the CSB pin to low, the 164x124 sensor

starts to produce a signal according to the amount of the light integrated in pixels. An entire raw data is then fed

to a CDS readout array to reduce FPN noise and reset noise. A differential signal is then read out serially and fed

to a programmable gain amplifier (PGA) followed by a 10-bit A/D converter.

Voltage reference block generates all necessary voltage and current for sensor array and analog circuit.