The document discusses the Carry Select Adder (CSLA), highlighting its architecture with dual Ripple Carry Adders (RCA) and multiplexers for efficient arithmetic operations. It details the implementation of low power digital designs using Gate Diffusion Input (GDI) techniques, showing comparisons in transistor count, delay, and power consumption between conventional CSLA and GDI designs. Additionally, it references various studies and conferences on advancements in low power and high-speed digital circuit designs.

1. Guided By: Presented By:
Mr. Sandeep Srivastav Dinesh kr Yadav
Nishant Yadav

2.  Carry Select Adder (CSLA) is a fast adder which is
used in the data processing processors for performing fast
arithmetic operations.
 The carry-select adder generally consists of two ripple
carry adders and multiplexers .
 One RCA performs addition by assuming the input
carry is 0 and other RCA performs addition by assuming
the input carry is 1.
 MUX select the output according to the carry from
previous stage

3. 4-BIT CARRY SELECT ADDER(CSLA)

5. • Consider the Following Example
101 101 110
110 111 001
101
+110
101
+111
110
+001
111  0
000  1
100  0
101  1
1  011  0
1  100  1
1 100 100 111

6. Paper Name Publisher Description
Implementation and
comparision of effective
area architecture of CSA.
R. Priya and J. Senthil Kumar “2013
IEEE International Conference on
emerging trends on computing
,communication and nano
technology(ICECCN2013).
This is the main paper in which
conventional CSLA has been
implemented
Low Power Digital design
using modified GDI
method.
Padmanabhan Balasubramanian and
Johince John,2006, IEEE.
This technique allows reducing
power consumption, propagation
delay, and area of digital circuits
GDI Technique : A
Power-Efficient Method
for Digital Circuits
.
Kunal & Nidhi Kedia Department
of Electronics &
Telecommunication Engineering,
Synergy Institute of Engineering &
Technology, Dhenkanal, Odisha
This paper describes the design and
implementation of various digital
circuit using GDI technique

7.  Mentor graphics Pyxis Schematic.
 Technology Used 0.18 um

8. It consist of :-
Ripple Carry Adder
Multiplexer (4T)
Ripple Carry Adder is designed by
Full Adder(12T) connected in series.

17. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 0 0 0 1 1 1 0 1 0 1 0 0 1 0 A
1 0 1 0 1 0 1 0 1 0 1 0 0 0 0 0 B
1 0 1 1 1 0 0 0 1 1 1 1 1 0 0 1 0 Sum
1 1 0 1 0 1 0 1 0 1 0 1 0 0 0 0 A
1 0 1 0 1 0 1 0 1 0 1 0 0 1 0 1 B
1 0 1 1 1 1 1 1 1 1 1 1 1 0 1 0 1 Sum
1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 0 A
0 1 0 1 0 1 0 1 0 1 0 1 1 1 0 1 B
1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 Sum
1 0 1 0 1 0 1 0 1 0 1 0 0 0 0 1 A
0 1 0 1 0 1 0 1 0 1 0 1 1 1 0 1 B
0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 Sum
INPUT AND ITS CORRESPONDING OUTPUT OF THE 16-BIT
CSLA

18. S0 0110
S1 1001
S2 0111
S3 0001
S4 1101
S5 1101
S6 1101
S7 1101
S8 1101
S9 0101
S10 0101
S11 0101
S12 1101
S13 1101
S14 1101
S15 0001
C_OUT 1110
OUTPUT COMBINATION OF THE 16-BIT CSLA

22. 8 Transistor Full adder circuit is used.
MUX of 2 transistor is used.
The MUX and FA circuit is designed by using
GDI(gate diffusion input ) technique.

23. BASIC FUNCTIONS USING GDI
CELL
COMPARISON OF TRANSISTOR
COUNT OF GDI AND STATIC CMOS
N p G Outpu
t
Function
0 1 A A’ INV
0 B A A’B F1
B 1 A A’+B F2
1 B A A+B OR
B 0 A AB AND
C B A A’B+AC MUX
B’ B A A’B+B’
A
XOR
B B’ A AB+A’B
’
XNOR
fUNCTIO
N
GDI CMOS
INV 2 2
F1 2 6
F2 2 6
OR 2 6
AND 2 6
MUX 2 14
XOR 4 12
XNOR 4 12
NAND 4 4
NOR 4 4

24. 1.The GDI cell contains three
inputs :
-G (common gate input of
nMOS and pMOS),
-P (input to the source/drain of
pMOS), and
-N (input to the source/drain of
nMOS).
2. Bulks of both nMOS and
pMOS are connected to GND
and VDD respectively.
3. Basic GDI Cell

40. CONVENTIONAL
CSLA
CSLA USING GDI
TECHNIQUE
(WITHOUT BUFFER)
CSLA USING GDI
TECHNIQUE
(WITH BUFFER)
NUMBER OF
TRANSISTO
R
408 186
(54.41 % Saved
186+64=250 (In
worst case)
(38.72 %Saved)
DELAY 430.45 pS 217.35 pS
(49.50% Faster)
318.18 pS
(26.08 % Faster)
POWER 29.82 mW 27.169 mW 28.035 mW

41. 0
100
200
300
400
500
Conventional
CSLA
CSLA Using GDI CSLA using GDI
with buffer
No. of transitors
No. of transitors
0
50
100
150
200
250
300
350
400
450
500
Conventional CSLA CSLA using GDI CSLA using GDI with Buffers
Delay
Delay

42. 0
5
10
15
20
25
30
35
Conventional CSLA CSLA using GDI CSLA using GDI with Buffers
Power
Power
0
2000
4000
6000
8000
10000
12000
14000
Conventional CSLA CSLA using GDI CSLA using GDI with Buffers
PDP
Power
Delay

43. The Wallace tree has three steps:
o Partial Product Generation.
o Wallace Tree Implementation.
o Addition using RCA.

44. BLOCK DIAGRAM OF WALLACE TREE
MULTIPLIER

45. WALLACE TREE MULTIPLIER

46. SCHEMATIC OF WALLACE TREE MULTIPLIER
USING CMOS

47. SYMBOL OF WALLACE TREE MULTIPLIER USING
CMOS

48. A3
=1
A2
=1
A1
=1
A0
=1
B3
=1
B2
=1
B1
=1
B0
=1
1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 0 0 0 0 1
P7 P6 P5 P4 P3 P2 P1 P0
A=1111
B=1111 P=11100001
A=1000
B=1000 P=01000000
A=0001
B=0001 P=00000001

49. O/P WAVEFORM OF WALLACE TREE MULTIPLIER
USING CMOS

50. CONTD……………..

51. SCHEMATIC OF WALLACE TREE MULTIPLIER
USING GDI

54. CONVENTIONAL
WALLACE TREE
MULTIPIER
WALLACE TREE USING
GDI TECHNIQUE
NUMBER OF
TRANSISTOR
352 276
(21.5 % Saved)
DELAY 570.60 pS 1.413 nS (Slower)
POWER 9.89 mW 8.23mW

55.  Arithmetic Logic Unit
 High Speed Multiplications
 Advanced Microprocessors

56. 1 Design of a Low Power, High Speed, Energy Efficient Full Adder Using
Modified GDI and MVT Scheme in 45nm Technology International
Conference on Control, Instrumentation, Communication and
Computational Technologies (ICCICCT)
2 “Low Power Digital design using modified GDI method” Padmanabhan
Balasubramanian and Johince John,2006, IEEE.
3 Low-Power and High Speed CPL-CSA Adder
“N V Vijaya Krishna Boppana, Saiyu Ren, Henry Chen” Department of
Electrical Engineering, Wright State University, Dayton, Ohio, USA
4 Implementation and comparision of effective area architecture of CSA, R.
Priya and J. Senthil Kumar “2013 IEEE International Conference on
emerging trends on computing ,communication and nano technology
ICECCN2013

57.  “Multipliers using low power adder cells using 180nm Technology” Jyoti
Gupta,Amit Grover, Garish Kumar Wadhwa, 2013 International Symposium
on Computational and Business Intelligence
 “Implementation of Low Power 8-Bit Multiplier using Gate Diffusion Input
Logic” B.N. Manjunatha Reddy, H. N. Sheshagiri, Dr.B.R.VijayaKumar,
2014 IEEE 17th International Conference on Computational Science and
Engineering

58.  THANK YOU