A 2.6mW 2fps QVGA CMOS one-chip wireless camera with digital image transmission function for capsule endoscopes

This paper presents the design and implementation of a one-chip camera device for capsule endoscopes. A prototype image sensor chip which has 320 times 240 effective pixels was fabricated using 0.25 mum CMOS image sensor process. 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). With a 2.0 V power supply, the analog part consumes 950muW 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