Area reduction in CSLA with efficient delay management

Ch Gayatri, D Naveen

Abstract


Adders play a key role in the arithmetic processors. There are many ways to design an adder. The major disadvantage of digital adders are that its speed is limited due to delay occurred in carry propagation.  Carry select adder (CSLA) is one of the fastest adders used in many computational  systems to improve the carry propagation delay by independently generating multiple carries and then select a carry to generate the sum. But the area of CSLA increases with the use of dual RCAs. A CSLA with Binary to Excees-1 Converter (BEC) is designed to reduce the area of the CSLA, but the delay over head  is increasing.  To further decrease the area and to keep the delay constant or equal as basic CSLA, an add one circuit can be used to design a CSLA. This work proposes the design of 8-bit, 16-bit, 32-bit, 64-bit and 128-bit square root CSLA (SQRT CSLA) using BEC with significant reduction in area.


Keywords


CSLA, BEC, processor. SQRT CSLA

References


O. J. Bedrij, “Carry-select adder,” IRE Trans. Electron. Comput.,pp.340–344, 1962. [2] Y. Kim and L.-S. Kim, “64-bit carry-select adder with reduced area,”Electron. Lett., vol. 37, no. 10, pp. 614–615, May 2001.

B. Ramkumar, H.M. Kittur, and P. M. Kannan, “ASIC implementation of modified faster carry save adder,” Eur. J. Sci. Res., vol. 42, no. 1, pp. 53–58, 2010.

T. Y. Ceiang and M. J. Hsiao, “Carry-select adder using single ripple carry adder,” Electron. Lett., vol. 34, no. 22, pp. 2101–2103, Oct. 1998.

Y. He, C. H. Chang, and J. Gu, “An area efficient 64-bit square root carry-select adder for low power applications,” in Proc. IEEE Int. Symp. Circuits Syst., 2005, vol.4, pp. 4082–4085.

B. Ramkumar and Harish M Kittur, “Low-Power and Area-Efficient Carry Select

Adder” IEEE transactions on very large scale integration (VLSI) systems, vol. 20, no. 2, February 2012]

N. Weste and K. Eshragian, Principles of CMOS VLSI Designs: A System Perspective, 2nd ed., Addison-Wesley, 1985-1993.

Morinaka, H., Makino, H., Nakase, Y. et. al, "A 64 bit Carry Look-ahead CMOS adder using Modified Carry Select". Cz/stoin Integrated Circuit Conference, 1995, pages 585-588

Milos D. Ercegovac and Thomas Lang, “Digital arthimetic,” Morgan Kaufmann, Elsevier INC, 2004.

W.Jeong and K.Roy, “robust high- performance low power adder”,proc,of the Asia and South Pacific Design Automatin Conference,pp.503-506,2003

D.C Chen, L. M. Guerra,E. H. Ng, M. Potkonjak, D.P. Schultz and J. M. Rabaey, “An integrated system for rapid prototyping of high performance algorithm specific data paths,” in Proc. Application specific Array Processors, pp.134-148,Aug 1992.

N.Weste and D. Harris, CMOS VLSI Design. Reading, MA: Addison Wesley, 2004.

Z. Chen and I. Koren, “Techniques for yield enhancement of VLSI adders,” in Proc. Int. Conf. Appl. Specific Array Process., Strasbourg, France, Jul. 24–26, 1995, pp. 222–229.


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