Abstract
This paper presents the design and implementation of a one-chip camera device for capsule endoscopes. This experimental chip integrates functional circuits required for capsule endoscopes and digital image transmission function. The integrated functional blocks include an image array, a timing generator, a clock generator, a voltage regulator, a 10b cyclic A/D converter, and a BPSK modulator. It can be operated autonomously with 3 pins (VDD, GND, and DATAOUT).
A prototype image sensor chip which has 320x240 effective pixels was fabricated using 0.25μm CMOS image sensor process and the autonomous imaging was demonstrated. The chip size is 4.84mmx4.34mm. With a 2.0 V power supply, the analog part consumes 950μW and the total power consumption at 2 frames per second (fps) is 2.6mW. Error-free image transmission over a distance of 48cm at 2.5Mbps corresponding to 2fps has been succeeded with inductive coupling.
