Optimizing techniques for charge injection effect of pixels in CMOS image sensor

Analysis on the charge injection effect of the pixels in CMOS image sensor is discussed and the optimizing techniques for the effect is proposed in this paper. The pixel consists of a Pinned-Diode and several MOS switches with large size, which causes severe charge injection during normal pixel operations. Analysis on the dynamic range of the Pinned- Diode (PD), node reset, exposure signal-reading aiming at charge injection effect is implemented, based on which, optimizing techniques for the effect by employing appropriate time sequence and suitable voltages/controlling signals are proposed. The dynamic range of PD is improved by 26% and the charge injection effect on FD (Floating-Diffusion) node is suppressed by 80%.