scholarly journals A REVIEW OF LOW VOLTAGE AND LOW POWER CMOS ADDERS USING VLSI DESIGN IN VERILOG/VHDL

Author(s):  
Lokesh S

The dominant portion of power dissipation in CMOS adder circuits, due to logic transitions, varies as the square of the supply, significant savings in power dissipation may be exacted by operating with reduced supply voltage. If the supply voltage is reduced while threshold voltage stays same, the noise margins will reduce. Addition is a crucial process because it usually involve carry ripple steps which must propagate a carry signal from each bit to it’s higher bit position. This results in a substantial circuit delay. The adder which lies in the crucial delay path will effectively determine the system overall speed. To improve noise margins, the threshold voltages must also be made smaller. However subthreshold leakage current increases exponentially when threshold voltage is reduced. The higher static dissipation may then offset the reduction in transitions portion of the dissipation. Hence the devices needed to have threshold voltages that maximizes the net reduction in the dissipation. Addition is an obligatory operation that is crucial to processing the fundamental arithmetic operations. Due to the potential versatility of adders in this contemporary research field, the existing adders and adder designs currently intended for future low voltage and low power environments. This can be achieved by the CMOS adders namely Parallel Adder, Ripple Carry Adder(RCA), Carry Look Ahead Adder(CLA), Carry Select Adder(CSL), Carry Save Adder(CSA), Carry Skip Adder(CSK), Conditional Sum Adder(COS).

Threshold Inverter Quantization (TIQ) for applications of system-on-chip (SoC) depending on CMOS flash analog-to-digital converter (ADC). The TIQ technique which uses two cascaded CMOS inverters as a voltage comparator. However, this TIQ method must be created to meet the latest SoC trends, which force ADCs to be integrated with another electronic circuit on the chip and focus on low-power and low-voltage applications. TIQ comparator reduced the impact of variations in the process, temperature, and power supply voltage. Therefore, we obtained a higher TIQ flash ADC speed and resolution. TIQ flash ADC reduced / managed power dissipation. We obtain large power savings by managing the power dissipation in the comparator. Furthermore, the new comparator has a huge benefit in power dissipation and noise rejection comparative to the TIQ comparator [1]. The findings indicate that the TIQ flash ADC based on Modied mux attain heavy-speed transformation and has a tiny size, low-power dissipation and operation of lowvoltage compared to another flash ADCs.


2018 ◽  
Vol 27 (10) ◽  
pp. 1850155 ◽  
Author(s):  
Jie Jin ◽  
LV Zhao

A low voltage low power fully integrated chaos generator is presented in this paper. Comparing with the conventional off-the-shelf electronic components-based chaos generators, the designed circuit is fully integrated, and it achieves lower supply voltage, lower power dissipation and smaller chip area. The proposed fully integrated chaos generator is verified with GlobalFoundries 0.18[Formula: see text][Formula: see text]m CMOS 1P6M RF process using Cadence IC Design Tools. The simulation results demonstrate that the fully integrated chaos generator consumes only 17[Formula: see text]mW from [Formula: see text]2.5[Formula: see text]V supply voltage. Moreover, the chip area of the chaos generator is only 1.755[Formula: see text]mm2 including the testing pads, and it has a wide range of practical application prospects.


Multiplier is the most basic component present in any digital system. These multipliers are mainly used in Digital Signal and Image Processing applications. In applications like image detection latest sophisticated algorithms like CNN are used which contains MAC units in their design. The multiplier used in MAC unit requires huge memory, offers high latency and consumes more power. There are many algorithms such as Combinational, Sequential and Array Multiplication Algorithms which helps in designing Multiplier. The major drawback in all designs is circuit complexity. The problem of latency and power dissipation are also present. Considering all the drawbacks present in those algorithms this paper proposes the usage of Wallace Tree Algorithm which consumes less power and has low latency. Also, there are many ways to add the final stage of partial products generated such as Carry Look Ahead adder, Carry Select Adder etc. This paper uses both Carry Select Adder and Ripple Carry Adder for performing final addition of partial products. All previous partial products are added using Half adders and Full adders. The Multiplier is designed using VHDL in Xilinx ISE and Vivado Platform.


2019 ◽  
Vol 8 (4) ◽  
pp. 10650-10653

The main aim of electronics is to design low power devices due to the prevalent usage of powered gadget. Ultra low voltage operation of memory cells has become a subject of a lot of interest because of its applications in terribly low energy computing. The stable operation of static random access memory (SRAM) is important for the success of low voltage SRAM and it is achieved by parameter variations of scaled technologies. The power consumption and access time of the SRAM is also a complex parameter due to the unavoidable switching activities of the number of transistors used for different blocks like, SRAM cell, access transistors, pre-charge circuit, sense amplifier and decoders. It has been shown that conventional 6T SRAM fail to achieve low power and delay operation. The proposed 10T SRAM design gives an approach towards the hold power dissipation. The designed circuit has 10 transistors out of that 2 transistors are used as sleep transistor. The sleep transistors are used as switches. Such as header and footer switches and the switches are turned on during active mode of operations and turned off during idle or standby mode of operations. The designed SRAM cell also has conducting pMOS circuit, which can reduces the total power dissipation. The SRAM cell is simulated by using Cadence tool. A supply voltage of 1.8V is used which makes it enough for low power applications. The power obtained as 761.7mW, which reduces 15% of conventional 6T SRAM design. The delay obtained as 125.6ns, which reduces 45% of conventional 6T SRAM.


2015 ◽  
Vol 10 (2) ◽  
pp. 74-80
Author(s):  
Alfredo Olmos ◽  
Fabricio Ferreira ◽  
Fernando Paixão Cortes ◽  
Fernando Chavez ◽  
Marcelo Soares Lubaszewski

This paper presents the design and application of a CMOS sub-1V voltage reference using a 2-transistor Self-Cascode MOSFET (SCM) structure able to get low power consumption, temperature compensation, and small area. An efficient design procedure applied to this simple topology relying on NMOS transistors with different threshold voltages allows attaining large immunity against bias current and supply voltage variations. The two transistors can operate in weak, moderate, or strong inversion making the design flexible in terms of area and power consumption. Implemented in a > 0.18mm standard CMOS technology, the circuit provides a 400mV voltage reference with a variation of ±0.18% from -20°C to 75°C (or less than 15ppm/°C), operates from 3.6V down to 800mV while biased with a 5nA resistor-less PTAT current source that varies ±30% over PVT, and consumes less than 20nA with an area of 0.01mm2. The same concept was used to create a temperature compensated voltage drop with regard to a monitored power supply voltage but using a 2-PMOS SCM structure with transistors of different threshold voltages. These two circuits were adopted as part of a Power Management (PM) system for RFID tag applications. The PM includes a LDO voltage regulator and a low voltage detector that require both the voltage reference and the low voltage monitor. The LDO regulated output voltage and the trip-point of the voltage detector vary +/-5.5% and +/-3.3%, respectively, over temperature, without trimming.


2014 ◽  
Vol 23 (08) ◽  
pp. 1450108 ◽  
Author(s):  
VANDANA NIRANJAN ◽  
ASHWANI KUMAR ◽  
SHAIL BALA JAIN

In this work, a new composite transistor cell using dynamic body bias technique is proposed. This cell is based on self cascode topology. The key attractive feature of the proposed cell is that body effect is utilized to realize asymmetric threshold voltage self cascode structure. The proposed cell has nearly four times higher output impedance than its conventional version. Dynamic body bias technique increases the intrinsic gain of the proposed cell by 11.17 dB. Analytical formulation for output impedance and intrinsic gain parameters of the proposed cell has been derived using small signal analysis. The proposed cell can operate at low power supply voltage of 1 V and consumes merely 43.1 nW. PSpice simulation results using 180 nm CMOS technology from Taiwan Semiconductor Manufacturing Company (TSMC) are included to prove the unique results. The proposed cell could constitute an efficient analog Very Large Scale Integration (VLSI) cell library in the design of high gain analog integrated circuits and is particularly interesting for biomedical and instrumentation applications requiring low-voltage low-power operation capability where the processing signal frequency is very low.


2021 ◽  
Vol 11 (2) ◽  
pp. 19
Author(s):  
Francesco Centurelli ◽  
Riccardo Della Sala ◽  
Pietro Monsurrò ◽  
Giuseppe Scotti ◽  
Alessandro Trifiletti

In this paper, we present a novel operational transconductance amplifier (OTA) topology based on a dual-path body-driven input stage that exploits a body-driven current mirror-active load and targets ultra-low-power (ULP) and ultra-low-voltage (ULV) applications, such as IoT or biomedical devices. The proposed OTA exhibits only one high-impedance node, and can therefore be compensated at the output stage, thus not requiring Miller compensation. The input stage ensures rail-to-rail input common-mode range, whereas the gate-driven output stage ensures both a high open-loop gain and an enhanced slew rate. The proposed amplifier was designed in an STMicroelectronics 130 nm CMOS process with a nominal supply voltage of only 0.3 V, and it achieved very good values for both the small-signal and large-signal Figures of Merit. Extensive PVT (process, supply voltage, and temperature) and mismatch simulations are reported to prove the robustness of the proposed amplifier.


2021 ◽  
Vol 2089 (1) ◽  
pp. 012080
Author(s):  
M. Srinivas ◽  
K.V. Daya Sagar

Abstract Currently, energy consumption in the digital circuit is a key design parameter for emerging mobile products. The principal cause of the power dissipation during idle mode is leakage currents, which are rising dramatically. Sub-threshold leakage is increased by the scaling of threshold voltage when gate current leakage increases because oxide thickness is scaled. With rising demands for mobile devices, leakage energy consumption has received even greater attention. Since a mobile device spends most of its time in standby mode, leakage power savings need to prolong the battery life. That is why low power has become a significant factor in CMOS circuit design. The required design and simulation of an AND gate with the BSIM4 MOS parameter model at 27 0C, supply voltage of 0,70V with CMOS technology of 65nm are the validation of the suitability of the proposed circuit technology. AND simulation. The performance parameters for the two AND input gate are compared with the current MTCMOS and SCCMOS techniques, such as sub-threshold leakage power dissipations in active and standby modes, the dynamic dissipation, and propagation period. The proposed hybrid super cutoff complete stack technique compared to the current MTCMOS technology shows a reduction in sub-threshold dissipation power dissipation by 3. 50x and 1.15x in standby modes and active modes respectively. The hybrid surface-cutting technique also shows savings of 2,50 and 1,04 in power dissipation at the sub-threshold in standby modes and active modes compared with the existing SCCMOS Technique.


Author(s):  
Ming-Cheng Liu ◽  
Paul C.-P. Chao ◽  
Soh Sze Khiong

In this paper a low power all-digital clock and data recovery (ADCDR) with 1Mhz frequency has been proposed. The proposed circuit is designed for optical receiver circuit on the battery-less photovoltaic IoT (Internet of Things) tags. The conventional RF receiver has been replaced by the visible light optical receiver for battery-less IoT tags. With this proposed ADCDR a low voltage, low power consumption & tiny IoT tags can be fabricated. The proposed circuit achieve the maximum bandwidth of 1MHz, which is compatible with the commercial available LED and light sensor. The proposed circuit has been fabricated in TSMC 0.18um 1P6M standard CMOS process. Experimental results show that the power consumption of the optical receiver is approximately 5.58uW with a supply voltage of 1V and the data rate achieves 1Mbit/s. The lock time of the ADCDR is 0.893ms with 3.31ns RMS jitter period.


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