Buffered Direct Injection of Photocurrents into Charge-Coupled Devices

In this paper we introduce a new and novel method for improving the coupling between photovoltaic IR detectors and CCD signal processors. This new coupling scheme, buffered direct injection (BDI), is a method for improving the direct injection of a signal current into a CCD. The buffered direct injection structure is formed by incorporating a simple amplifier into the conventional direct injection structure. The new structure formed is amenable to LSI technology and offers significant improvements over conventional injection. Improvements in noise, injection efficiency, injection bandwidth and dc offset realized by the BDI approach over conventional coupling structures (e.g., direct injection) are discussed. Experimental evidence is presented to corroborate the analysis.