Sources of Power Dissipation in CMOS Circuits

Author(s):  
Dimitrios Soudris ◽  
Antonios Thanailakis
2020 ◽  
Vol 18 (3) ◽  
pp. 210-215
Author(s):  
Shubham Tayal ◽  
Sunil Jadav

Power dissipation and delay are the challenging issues in the design of VLSI circuits. This manuscript explores joint effect of Self-Bias transistors (SBTs) and Optimum Bulk Bias Technique (OBBT) on CMOS circuits. Earlier investigations on SBTs shows decrease in power dissipation of combinational as well as sequential circuits. We extend the analysis by studying the effect of OBBT on the static and dynamic power of CMOS circuits with SBTs coupled amid the pull-up/down network and the supply bars. Extensive SPICE simulations have been carried out in 0.18 μm technology. Results demonstrate that, a 73% drop in power in case of combinational circuits and 43% in case of sequential circuits can be accomplished by engaging OBBT in digital circuits. Trade-off between power and delay is also been presented.


Author(s):  
Mohasinul Huq N Md ◽  
Mohan Das S ◽  
Bilal N Md

This paper presents an estimation of leakage power and delay for 1-bit Full Adder (FA)designed which is based on Leakage Control Transistor (LCT) NAND gates as basic building block. The main objective is to design low leakage full adder circuit with the help of low and high threshold transistors. The simulations for the designed circuits performed in cadence virtuoso tool with 45 nm CMOS technology at a supply voltage of 0.9 Volts. Further, analysis of effect of parametric variation on leakage current and propagation delay in CMOS circuits is performed. The saving in leakage power dissipation for LCT NAND_HVT gate is up to 72.33% and 45.64% when compared to basic NAND and LCT NAND gate. Similarly for 1-bit full adder the saving is up to 90.9% and 40.08% when compared to basic NAND FA and LCT NAND.


Author(s):  
S.C. Wagaj ◽  
◽  
S.C. Patil ◽  

In this paper it has been demonstrated that a shielded channel made by varying the side gate length in silicon-on-nothing junctionless transistor not only improves the short channel effect but also improve the performance of CMOS circuits of this device. The proposed device shielded channel dual gate stack silicon on nothing junctionless transistor (SCDGSSONJLT) drain induced barrier lowering (DIBL), cut-off frequency and subthreshold slope are improved by 20%, 39% and 20% respectively over the single material gate silicon on insulator junctionless transistor (SMG SOI JLT). The proposed device CMOS inverter fall time Tf (pS) and noise margin improves by 50% and 10% compare to shielded channel silicon on insulator junctionless transistor (SCSOIJLT). It has been observed that circuit simulation of CMOS inverter, NAND and NOR of proposed device. The static power dissipation in the case of proposed SCDGSSONJLT device are reduced by 45%, 81% and 83% respectively over the SMGSOIJLT. Thus, significant improvement in DIBL, cut-off frequency, propagation delay and static power dissipation at low power supply voltage shows that the proposed device is more suitable for low power CMOS circuits.


2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000243-000250 ◽  
Author(s):  
E. Boufouss ◽  
L. A. Francis ◽  
P. Gérard ◽  
M. Assaad ◽  
D. Flandre

We present three ultra-low-power CMOS circuits: a temperature sensor, a voltage reference and a comparator developed for an ultra-low-power microsystem (ULP-MST) aiming at temperature sensing in harsh environments. The microsystem has 3 main functions: detecting a user-defined temperature threshold T0, generating a wake-up signal that turns on a data-acquisition microprocessor (located in a safe area) above T0, and measuring temperatures above T0. To achieve ultra-low-power operation, the three CMOS circuits are implemented in Silicon-on-Insulator (SOI) CMOS technology and are optimized to work in the subthreshold regime of the transistors. Since our application is mainly for harsh environment (i.e. high temperature and radiation), the chip has been designed using a suitable 1-μm SOI-CMOS technology. Simulations have been performed over the different process corners to verify functionality after fabrication. The typical power dissipation at high temperature (up to 240°C) is less than 100 μW at 5 V supply voltage. Measurements have validated correct operation in the temperature range from −40°C to 300°C before radiation and to 125°C after radiation up to now which will be extended further with a new set-up. Irradiation has been performed from 10 to 30 kGy. Such very high doses cause a shift down of output voltage values, which leads to a change of the temperature detection level and also increases the power dissipation by up to six times. Annealing effects help the partial recovery of the device operation at high temperature and the remote microprocessor enables calibration after radiation to readjust the temperature detection level.


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