Abstract
In this work we present a sub-1V pulse-width-modulation (PWM) CMOS image sensor. Ultra-low power consumption is achieved through the sub-threshold pixel bias, time-to-digital conversion and the array-level asynchronous counter. The 2-step readout scheme is adopted to improve the frame rate up to 68fps. The prototype chip with 64×64 array has been fabricated in a 0.18μm 1P6M CMOS process. Minimum functional analog supply of 0.36V can be achieved, and the whole chip consumes only 1.14μW at 13fps, or 21.4pW/frame-pixel. The dynamic range and FPN are measured to be 70dB and 0.49% respectively.
