Charge coupled device output circuit structure

Abstract

This CCD structure comprises a substrate floating diffusion region from which an output signal is taken and a drain diffusion spaced apart from the output diffusion and from which the charge is returned. An electrode to be pulsed is placed immediately preceding the floating diffusion and a plurality of electrodes is interposed between the two diffusions. The first such electrode beyond the output floating diffusion is operated as a reset pulse gate electrode and the last such electrode before the drain diffusion is operated as a drain pulse gate electrode, while the intermediate electrode(s) have phased clock pulses applied thereto in synchronism with such phased clock pulses applied to other electrodes of the overall CCD circuit arrangement. The preceding pulsed electrode serves to extend the lower limit of the potential change of the floating diffusion. The interposed electrodes permit signal charge to be transferred out of the floating diffusion into a gate-induced potential well instead of directly into the drain diffusion, extending the upper limit of potential change of the floating diffusion. Further, the drain gate isolates the drain diffusion from the preceding final CCD stages thereby obviating 'charge sloshing'.