This paper presents a novel low power configurable pulse width modulation digital pixel sensor. The pixel can be configured as either an image sensor or an energy harvester. In both configurations, the pixel's photodiode anode is connected to the harvesting bus. Achieving low power consumption and high frame rate features was made possible by utilizing an event generator in place of a conventional comparator. In the proposed structure, a global counter serves as an analog-to-digital converter, and a variable clock frequency is applied to the global counter to non-uniformly quantize integration time. This approach provides the sensor with a high dynamic range. The design was simulated using 1-poly 6-metal 180-nm standard technology. The results demonstrate a dynamic range exceeding 120 dB and a pixel power consumption of 0.917 nW at 500 fps. Also, the harvested power from a 64×64-pixel array was measured to be 17.92 μW.
Abdollahi et al. (Wed,) studied this question.