In this paper, a CMOS image sensor for auto exposure control and local brightness adaptation is proposed. Asynchronous address event representation readout scheme is used to find and reset a pixel that requests to be readout. By finding a pixel that has the lowest photo diode voltage among pixel arrays, one cycle of the photo diode reset and readout is completed. This readout scheme makes output request rates of the pixel array to be exposure controlled request rates by adapting the integration voltage to the brightness of the scene. The integration voltage represents voltage variation range at the photo diode before the pixel requests to be reset and readout. For enhancing sensor dynamic range, local brightness adaptation is achieved by distributing sensor readout bandwidth to the pixels in the selected window kernel. To implement proposed readout scheme, PMOS source follower (Loser-Follower), Loser-Take-All circuit, and feedback reset are used to find the address of the pixel that has lowest photo diode voltage and reset with pixel FPN reduction. HSPICE simulation results estimate that 350ns duration is needed to readout a pixel. Proposed readout scheme is verified by programming the sensor operation with Visual C++. The dynamic range of proposed sensor with local brightness adaptation is expected to be 75dB at uniform brightness and 24dB reflectance at 30fps.
