Study on a vision chip based on asynchronous operation

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In the first year we have studied a vision chip based on non-accumulation mode and its application. First of all we have evaluated photo-transistors, which are essential devices to non-accumulation mode. Next by using the non-accumulation mode we have proposed a vision chip which can take image without being affected by surrounding illumination. This chip can extract only modulated signals from reflected light signals. The simulation results have showed a proper operation. The proposed chip consists of photo-sensing part, a demodulation circuit, an averaging circuit, and a sensitivity correction circuit. To detect a small modulated signals on a strong background illumination, Darlington connected photo-transistors have been employed due to their high gain. To suppress the non-uniform gain we have introduced a sensitivity correction circuit. We have designed the circuits and demonstrated their effectiveness by HSPCIE simulation.In the second year we have studied on high performance of photo-sensing circuit. Floating diffusion has been used to improve the sensitivity and suppress the noise. Standard CMOS fabrication process has been applied to make two types of sensor chip ; photo-gate type and photodiode type. The used process is 0.35μm double poly double metal CMOS.We have preliminary showed the fundamental characteristics of photo-gate type sensor.