Download realization of ternary-logic based shift up, shift down using mosfet

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ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 4, Issue 4, July-August, 2013, pp. 240-247
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IJECET
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REALIZATION OF TERNARY-LOGIC BASED SHIFT UP, SHIFT DOWN
USING MOSFET
Virang Jhaveri1, Yash Jain2, Vishesh Kamdar3, Shanay Kothari4
1
(EXTC, D.J. Sanghvi College of Engineering, Mumbai, India)
(EXTC, D.J. Sanghvi College of Engineering, Mumbai, India)
3
(EXTC, D.J. Sanghvi College of Engineering, Mumbai, India)
4
(EXTC, D.J. Sanghvi College of Engineering, Mumbai, India)
2
ABSTRACT
In this paper, we discuss the practical realization of basic shift up and shift down ternary
based logic gates. Current bit based circuitry limits the number of gate design. The present CMOS
technology does not use depletion mode transistors. The prime objective in our work is to minimize
the number of transistors used whilst retaining functionality, eliminate the use of resistors to lower
the power consumption and reduce delay propagation. The reduction in the number of transistors is
main focus as that enabled a more compact design.
Keywords: Basic Gates, Integrated Circuit, MOSFET, Multi-Value Logic Design, Shift Up Down,
Ternary Logic
I.
INTRODUCTION
When we view ternary logic from a mathematically perspective it becomes apparent that
there are twenty seven possible gate designs. Whereas when we consider a binary system for a dual
bit input there is only the possibility of constructing four gates. Hence, it is apparent that the lack of
hitherto unseen logic gates in the field of ternary logic has hampered further research in it. The use of
new gates permits us to radically redesign familiar elements such as adders, subtractors,
multiplexers, demultiplexers, encoders and decoders. Current ternary based design research is
focused in the field of increasing the efficiency of previously designed ternary gates and ‘porting’
existing binary systems with ternary ones.
Theoretically, the advantages offered are shorter decimal representation; ternary logic
representation offers us a novel way of dealing with recurring decimals since it uses a base 3.
Although we compromise accuracy for better computation the loss of data is minimal.
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ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August
August (2013), © IAEME
II. TERNARY LOGIC
Ternary logic functions are those functions where Kleene logic augments the conventional
true and false of Boolean logic with a third value; unknown, indeterminate, irrelevant, or both. In this
paper, the assignments of different numerical equivalents to these values are as follows: 0, 1, and 2
represent false, undefined,
fined, and true, respectively. [1]
Any n variable {X1,...,Xn}
..,Xn} ternary function f (X) is defined
defined as a logic function mapping
{0,1,2} n to {0, 1, 2}, where X {X1,...,Xn}. The basic operations of ternary logic can be de
defined as
follows, where
Xi, Xj= {0, 1, 2} [13]:
Xi+ Xj= max{Xi, Xj}
Xi• Xj= min{Xi, Xj}
Xi`= 2− Xi
where the operations +,•,` and are referred to as the OR, AND, and NOT in terna
ternary logic,
respectively. The fundamental gates in the design of digital systems are the inverter, the NOR gate,
and the NAND gate. The assumed logic symbols are shown in Table
Table I. The ternary gates are
designed according to the convention de
defined by (1).
Table (1)
Voltage
-5
0
5
Symbol
0
1
2
III. STEP DOWN GATE
Step down gate is divided in two sections.
(i)
Limiting Circuit
ircuit
(ii)
Inverter Circuit
Limiting circuit for step down gate
Fig (1) – Simulated on LTSPICE
Fig.
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
Working – Limiting Circuit
The limiting circuit is designed on the fact that the pmos conducts when the gate voltage is less than
its Drain voltage and nmos conducts when the gate voltage is greater than its Drain voltage.
When -5v is supplied via V2 The gate voltage of pmos(-5v) is less than its drain voltage (5v) and
The gate voltage of
nmos(-5v)is less than its drain voltage therefore pmos conducts and nmos doesn’t conduct .The
output is 5v
When 0v is supplied via V2 The gate voltage of pmos(0v) is less than its drain voltage (5v) and The
gate voltage of nmos is same as its drain voltage therefore pmos conducts and nmos doesn’t
conduct. The output is 5v
When 5v is supplied via V2 The gate voltage of pmos(5v) is same as its drain voltage (5v) and The
gate voltage of nmos(5v) is greater than its drain voltage(0v) therefore nmos conducts and pmos
doesn’t conduct.The output is 0v
The table(2) shows the truth table of the limiting circuit where the input and output are represented in
their respective logic states.
Table (2)
Input
0
1
2
Output
2
2
1
The Graph (1) shows the simulation of limiting circuit where the blue line is the output and
the green line is the input. The input varies from -5V to 5V and the o/p varies from 5v to 0 V
Graph(1)
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
The limiting circuit is the connected to a inverter circuit which is represented by Table (3)[2]
Table (3)
Input
0
1
2
Output
2
1
0
Fig. (2) (Step Down Gate)
Truth Table (Step Down Gate)
IN
0
1
2
Step Down(IN)
0
0
1
Working – Step Down
The M2 and M4 complement the the trits provided by M1 and M3 present in the first stage..
When IN is 0V , M3 is activated therefore the output at mid stage is 5V and then it goes thru the
NOT gate and the output is -5V which is the required output
When IN is -5V , M3 is activated therefore the output at mid stage is 5V and then it goes thru the
NOT gate and the output is -5V which is the required output
When IN is 5V , M1 is activated therefore the output at mid stage is 0V and then it goes thru the
NOT gate and the output is 0V which is the required output.
The graph (2) shows the the simulation of the shift down gate.The red line is the zero
reference line, the green line is the input line which starts at -5 V and the increases towards 5 V. The
blue line is the output line.
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
Graph (2)
IV. STEP UP GATE
Step Up Gate is divided in two sections.
(i). Limiting Circuit
(ii). Inverter Circuit
Limiting circuit for step up gate
Fig. (3) – Simulated Using LTSPICE
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
Working – Limiting Circuit
The limiting circuit makes is designed on the fact that the pmos conducts when the gate voltage is
less than its Drain voltage and nmos conducts when the gate voltage is greater than its Drain voltage.
When -5v is supplied via V2 The gate voltage of pmos(-5v) is less than its drain voltage (0v) and
The gate voltage of nmos (-5v)is same as its drain voltage therefore pmos conducts and nmos
doesn’t conduct.The output is 0v
When 0v is supplied via V2 The gate voltage of pmos(0v) is same as its drain voltage (5v) and The
gate voltage of nmos (0v) is greater than its drain voltage(-5v) therefore nmos conducts and pmos
doesn’t conduct.The output is -5v .
When 5v is supplied via V2 The gate voltage of pmos(5v) is greater than its drain voltage (0v) and
The gate voltage of nmos(5v) is greater than its drain voltage(-5v) therefore nmos conducts and
pmos doesn’t conduct.The output is -5v
The table(4) shows the truth table of the limiting circuit where the input and output are represented in
their respective logic states.
Table (4)
Input
0
1
2
Output
1
0
0
The graph (3) shows the simulation of limiting circuit where the blue line is the output and
the green line is the input.the i/p varies from -5v to 5v and the o/p varies from 0 V to -5 V.
Graph (3)
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
The limiting circuit is the connected to a inverter circuit which is represented by table (5)[2]
Table (5)
Input
0
1
2
Output
2
1
0
Fig. (4) (Step Up Gate)
Truth Table (step up gate)
IN
0
1
2
Step Up (IN)
1
2
2
Working – Step Up Gate
The M2 and M4 complement the the trits provided by M1 and M3 present in the first stage..
When IN is -5 V , M3 is activated therefore the output at mid stage is 0V and then it goes thru the
NOT gate and the output is 0V which is the required output
When IN is 0 V , M1 is activated therefore the output at mid stage is -5V and then it goes thru the
NOT gate and the output is 5V which is the required output
When IN is 5 V , M1 is activated therefore the output at mid stage is -5V and then it goes thru the
NOT gate and the output is 5V which is the required output
The graph (4) shows the simulation of the shift down gate. The red line is the zero reference line,
The green line is the input line which starts at -5 V and the increases towards 5 V. The blue line is
the output line.
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International Journal of Electronics and Communication Engineering & Technology (IJECET),
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 4, July-August (2013), © IAEME
Graph (4)
V. IMPLEMENTATIONS
The above circuits have been implemented and simulated in LT Spice.
VI. APPLICATION S
The immediate forseeable applications of the shift up and shift down ternary gates are their
use to develop new designs for traditional combinational circuits like adders and subtractors. The shift
up and shift down gate design can be used to realize other still unknown gate designs.
VII. FUTURE SCOPE
Since the data usage by simple as well as complex circuitry goes on increasing, we are
reaching a point where the limitations of Moores law become self apparent. Hence there is an
immediate real world need to replace our ‘bit’ based systems with the ‘trit’ based system. The use of
these gates is to build the combinational circuits required to build a ternary ALU.
VIII. REFERENCES
1. Standard Ternary Logic by by Douglas W. Jones THE UNIVERSITY OF IOWA Department of
Computer Science http://homepage.cs.uiowa.edu/~jones/ternary/logic.shtml.
2. Implementation of Ternary Based Logic Gates. Virang Jhaveri, Shanay Kothari, Yash Jain
ISBN No. 9789382880233.
3. Amit Nigam, “Enrichment Towards the Design of Efficient 4 Bit Reversible Subtractor using
TR Gate: A Low Power Application”, International Journal of Electronics and Communication
Engineering & Technology (IJECET), Volume 4, Issue 4, 2013, pp. 1 - 12, ISSN Print:
0976- 6464, ISSN Online: 0976 –6472.
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