A Novel PWM Digital Pixel Sensor with In-pixel Memory Structure

in this paper, by using an event generator instead of conventional comparator a PWM pixel with in-pixel memory is proposed. A control unit is used for providing the global counter with variable frequency in order to compensate the reverse relationship between the integration time and the photocurrent, in addition to the nonlinearity forced by the event generator. Simulations have been done in a one-poly, six-metal 180nm standard technology. The results show that the proposed pixel achieves more than 140dB dynamic range while the power consumption of the pixel is 3.507nW at 33fps.