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Charge Coupled Device Shift Register Read/Write/Regeneration Circuit

IP.com Disclosure Number: IPCOM000076986D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Terman, LM: AUTHOR

Abstract

Fig. 1 shows a simple circuit which carries out the read, write, and regeneration functions for a charge-coupled device (CCD) shift register. The operation of charge-coupled devices is well known/1/ and will not be discussed, except as it relates to the operation of the arrangement of Fig. 1. Diffusion 2 is connected to a voltage reference Vref, and phi V is a pulsed source. Also, the plate associated with the phi 1' pulsed source is made larger than in previous arrangements.

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Charge Coupled Device Shift Register Read/Write/Regeneration Circuit

Fig. 1 shows a simple circuit which carries out the read, write, and regeneration functions for a charge-coupled device (CCD) shift register. The operation of charge-coupled devices is well known/1/ and will not be discussed, except as it relates to the operation of the arrangement of Fig. 1. Diffusion 2 is connected to a voltage reference Vref, and phi V is a pulsed source. Also, the plate associated with the phi 1' pulsed source is made larger than in previous arrangements.

At the end of phi 2' node N1 is at one of two potentials, depending upon whether a "1" or a "0" was shifted in from phi 2'. When phi 1 and phi 1' are pulsed, charge will be transferred from diffusion 2 into the potential wells under phi 1 and phi 1' if the voltage in N1 is large enough to form a channel under the associated control gate. Because of tolerances, etc., the 1 and 0 potentials at N1 will vary over ranges, as shown in Fig. 2. Diffusion 2 is returned to a potential such that the sum of that potential and the surface threshold lies between the minimum up or 1 level, and the maximum down or 0 level. This allows no charge transfer in the latter case, and charge transfer in the former. Thus the zero level is reset to a no charge condition. For the 1 case, the well under phi 1 can only fill up to the potential or diffusion 2. Therefore, this plate is made larger than other phi 1 plates in the system, such that it can h...