Charge coupled device ripple adder with nearly instantaneous carry propagation
US4464728A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 18, 1981 |
| Grant date | Aug 7, 1984 |
| Priority date | — |
| Expiry date | Sep 18, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2207/4808
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A ripple adder is implemented as a charge coupled device in such a manner that each carry bit propagates between succeeding full adder stages substantially simultaneously as each stage computes the sum of its two bits, so that the addition in each full adder stage may be carried out in parallel rather than in succession. The i.sup.th one of the CCD full adder stages includes charge transfer means for receiving two bits of charge, namely the i.sup.th bits of the two n-bit words which are to be summed. First and second charge storage means are provided, each having the capacity to store one bit of charge only, so that excess charge will cause an overflow. Means for sensing overflow charge stored in the second charge storage means is connected to a carry bit charge injector in the i.sup.th +1 adder stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.