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School of Aeronautics (Neemrana) provides platform and environment for open discussions and interactions between the faculty and students and is designed to ignite and serve the urge to explore and learn beyond boundaries.


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Low Power Techniques in VLSI

PHYSICS Posted on Mon, January 11, 2016 15:12:32

Certain class of logic circuits
called adiabatic logic deals
the probability of further decreasing the energy dissipated during the
switching activity, and the possibility of reusing or recycling, some amount of
the energy drawn from the power supply. To undertake this goal, the circuit
topology and the operation principles should have to be modified, sometimes
significantly. The amount of energy recycling achievable using adiabatic
techniques is also determined by the fabrication technology, the voltage swing
and switching speed.

List of adiabatic logic families in approximate
chronological order

1. Recovered energy logic (REL)

2. Charge recovery logic (CRL)

3. Split level charge recovery logic
(SCRL)

4. Adiabatic dynamic logic (ADL)

5. Clocked adiabatic logic (CAL)

6. Improved clocked adiabatic logic
(ICAL)

7. Efficient charge recovery logic
(ECRL)

8. 2N-2N2P adiabatic logic

9. Positive feedback adiabatic logic
(PFAL)

10. Charge recycling differential
logic (CRDL)

11. Half rail differential logic
(HRDL)

12. Pass transistor adiabatic logic
(PAL)

13. Quasi static energy recovery
logic (QSERL)

14. NMOS energy recovery logic (NERL)

15. Bootstrapped charge recovery
logic (BCRL)

16. High efficient energy recovery logic (HERL)

Out of these, there are four families such as ECRL, 2N-2N2P, CAL and
ICAL that gives a clarification for the goodness of such circuts in terms of Energy Saving Factors, Static Power Dissipation and Delay: (Under 180 nm Technogy)

Adiabatic
type

ESF

CAL with
ICAL

1.075

CAL with
2N-2N2P

1.071

ECRL with
CAL

2.570

2N-2N2P with
ICAL

1.008

Adiabatic Types

Static power
Dissipation

CAL

49.08 pW

ICAL

2.4 µW

2N-2N2P

32.2 pW

ECRL

33.0 µW

Voltage (V)

CAL XOR (ns)

ICAL XOR (ns)

2N-2N2P XOR (ns)

0.9

0.69

0.15

1.95

1.0

0.65

0.62

1.83

1.2

0.61

0.58

1.72

1.3

0.59

0.57

1.69



Demand of Low Power in VLSI

PHYSICS Posted on Mon, January 11, 2016 14:55:35

In the earlier, the main concerns
of very large scale integration (VLSI) designer were cost, area, reliability
and performance; power consideration was generally secondary importance. In the
earlier few eras ago, the electronics productiveness has been experiencing an
exceptional issue in growth, thanks to the use of integrated circuits (IC) in
computing, telecommunications and user electronics. We have come a long way
from the single transistor years in 1958 to the current day Ultra Large Scale
Integration (ULSI) systems with more than 60 million transistors in a single
chip.
Power dissipation of VLSI integrated circuits is
traditionally a neglected subject. In earlier, the device packing density and
operating frequency were low enough that it was not a constraint in the
integrated circuits. This leads the steady growth of the operating frequency
and processing capacity per ICs, resulting in increasing power dissipation. A
need of low power VLSI design arises from such evaluation forces of ICs.

Another chief demand for low power integrated circuits and systems
comes from the environmental concerns. Modern offices are now furnished with
office automation equipment that consume large amount of power. A study by American Council for an Energy-Efficient
Economy estimated that office equipment account for 5% for the total US
commercial energy usage in 1997 and could rise to 10% by the year 2004 if no
actions are taken to prevent the trend
Ref.
1. A. P. Chandrakasn, S.
Sheng, and R. W. Broad, “Low Power CMOS Digital Design,” IEEE Journal of Solid-state Circuits,
Vol. 27, No. 04, pp. 473-484, April 1999.

2.J. M. RABAEY, AND M. PEDRAM, “Low Power Design Methodologies,” Kluwer Academic Publishers,
2002.



GaAs Single electron Transistor for high frequency

PHYSICS Posted on Tue, November 17, 2015 22:30:52

Semiconductor based electronic devices are being
scaled into nano-meters of dimension. Present electronics demands the better
material which will be reliable than the previous used semiconductor materials
such as silicon. Silicon has now the less capability and also not optimum in
all respect. Gallium Arsenide is now emerging good choice the other semiconductor like silicon and germanium. This
work presents the basic physics of the single electron transistor (SET) using
GaAs semiconductor material. The coulomb effect calculations in the SET,
mobility of GaAs in the SET and permittivity vs. frequencies in order of THz
depicts that GaAs SET may be used in the high frequency communication devices.