Novel Logarithmic Active Pixel Sensor with High Dynamic Range and High Output Swing

The logarithmic response complementary metal oxide semiconductor(CMOS) image sensor provides a wide dynamic range, but its drawback is the lack of simple fixed pattern noise(FPN) cancellation scheme. Designed is a novel logarithmic active pixel sensor(APS) with high dynamic range and high output swing. Firstly, the operation principle of mixed-model APS is introduced. The pixel can work in three operation modes by choosing the proper control signals. Then, FPN sources of logarithmic APS are analyzed, and double-sampled technique is implemented to reduce FPN. Finally, according to the simulation results, layout is designed and has passed design rule check(DRC), electronic rule check(ERC) and layout versus schematic(LVS) verifications, and the post-simulation results are basically in agreement with the simulation results. Dynamic range of the new logarithmic APS can reach about 140dB; and the output swing is about 750mV. Results show that by using double sampled technique, most FPN is eliminated and the dynamic range is enhanced.