scholarly journals A new circuit technique for reduced leakage current in Deep Submicron CMOS technologies

2005 ◽  
Vol 3 ◽  
pp. 355-358
Author(s):  
A. Schmitz ◽  
R. Tielert

Abstract. Modern CMOS processes in the Deep Submicron regime are restricted to supply voltages below 2 volts and further to account for the transistors' field strength limitations and to reduce the power per logic gate. To maintain the high switching performance, the threshold voltage must be scaled according with the supply voltage. However, this leads to an increased subthreshold current of the transistors in standby mode (VGS=0). Another source of leakage is gate current, which becomes significant for gate oxides of 3nm and below. We propose a Self-Biasing Virtual Rails (SBVR) - CMOS technique which acts like an adaptive local supply voltage in case of standby mode. Most important sources of leakage currents are reduced by this technique. Moreover, SBVR-CMOS is capable of conserving stored information in sleep mode, which is vital for memory circuits. Memories are exposed to radiation causing soft errors. This well-known problem becomes even worse in standby mode of typical SRAMs, that have low driving performance to withstand alpha particle hits. In this paper, a 16-transistor SRAM cell is proposed, which combines the advantage of extremely low leakage currents with a very high soft error stability.

2021 ◽  
Author(s):  
T. Santosh Kumar ◽  
Suman Lata Tripathi

Abstract The SRAM cells are used in many applications where power consumption will be the main constraint. The Conventional 6T SRAM cell has reduced stability and more power consumption when technology is scaled resulting in supply voltage scaling, so other alternative SRAM cells from 7T to 12T have been proposed which can address these problems. Here a low power 7T SRAM cell is suggested which has low power consumption and condensed leakage currents and power dissipation. The projected design has a leakage power of 5.31nW and leakage current of 7.58nA which is 84.9% less than the 7T SRAM cell without using the proposed leakage reduction technique and it is 22.4% better than 6T SRAM and 22.1% better than 8T SRAM cell when both use the same leakage reduction technique. The cell area of the 7T SRAM cell is 1.25µM2, 6T SRAM is 1.079µM2 and that of 8T SRAM is 1.28µM2all the results are simulated in cadence virtuoso using 18nm technology.


Author(s):  
Harekrishna Kumar ◽  
V.K Tomar

In this paper, a 9T SRAM cell with low power (LP9T) and improved performance has been proposed. This cell is free from half-select issue and works with single-ended read and differential write operation in the sub-threshold region. To evaluate the relative performance, the obtained characteristics of LP9T SRAM cell are compared with other state-of-the-art designs at 45-nm technology node. The read and write power dissipation of LP9T SRAM cell is reduced by [Formula: see text] and [Formula: see text] as compared to Conv.6T SRAM cell. In proposed cell, leakage power is reduced by [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] as compared to conventional 6T (Conv.6T), low power (LP8T), transmission gate 8T(TG8T), transmission gate 9T (TG9T), Schmitt trigger 9T (ST9T), and positive feedback control 10T (PFC10T) SRAM cells. This reduction in leakage power is attributed to stacking effect. LP9T SRAM cell also exhibits significant improvement in read/write access time as compared to all considered cells. Also, the read and write energy of proposed cell is lowest among all considered cells. The LP9T SRAM cell has [Formula: see text] and [Formula: see text] higher read and write stability as compared to Conv.6T SRAM cell. Proposed SRAM cell has the highest value of ON to OFF current ratio ([Formula: see text]) which signifies the highest bit-cell density among all considered cells. The LP9T SRAM cell occupies [Formula: see text] large area as compared to Conv.6T SRAM cell. The overall quality of SRAM cell is calculated through the electrical quality metric (EQM). It is observed that LP9T SRAM cell has the highest value of EQM in comparison to considered cells at 0.3[Formula: see text]V supply voltage.


2003 ◽  
Vol 16 (2) ◽  
pp. 205-214
Author(s):  
Sonja Richter ◽  
Stefan Bormann ◽  
Valentin Nakov

Silicon-on-insulator technologies are well suited for high temperature circuit design, due to low leakage currents. The reduction of leakage currents is especially important in large repetitive structures such as memories. This paper describes the layout development of a high temperature SRAM cell in a SOI Technology. First, the differences between SOI technologies and standard CMOS processes are presented. It is then discussed, how SOI specific circuit element behavior affects the layout design of different parts of the SRAM cell. Solutions for SOI specific problems are presented and advantages and disadvantages of SOI technologies in static random access memory design are shown.


Author(s):  
P. M. Adithyalal ◽  
Shankar Balachandran ◽  
Virendra Singh

2011 ◽  
Vol 10 (04n05) ◽  
pp. 755-759
Author(s):  
K. SUNIL KUMAR

In this work the impact of gate leakage on SRAM is described and two approaches for reducing gate leakage currents are examined in detail. In one approach, the supply voltage is reduced while in the other the potential of the ground node is raised. In both the approaches the effective voltage across SRAM cell is reduced in inactive mode using a dynamic self-controllable switch. Simulation results based on BPTM (Berkeley Predictive Technology Model) for 45 nm channel length device show that the scheme in which supply voltage level is reduced is more efficient in reducing gate leakage than the one in which ground node potential is raised. Results obtained show that 96% reduction in the leakage currents of SRAM can be achieved.


2018 ◽  
Vol 7 (4) ◽  
pp. 2521
Author(s):  
Tripti Tripathi ◽  
D. S. Chauhan ◽  
S. K. Singh

Leakage power is becoming a major concern in battery operated and hand held devices. With the ever reducing size of electronic devices and the use of memory in most of them, the need for low power devices is vastly increasing. These devices are either in active or standby mode of operation. Leakage power in standby mode of operation is of major concern and various methods to minimize it have been proposed at various stages of design cycle. This paper proposes fingering technique that can be used in 6T SRAM cell to reduce leakage power. Leakage power is calculated for 6T SRAM cell designed using two fingers in access transistors and on comparison with conventional 6T SRAM cell, significant reduction in leakage current is obtained. The layout has been designed in UMC 55nm technology using Cadence Virtuoso tool and it has been shown that the leakage power and delay can be reduced.  


2021 ◽  
Author(s):  
Harekrishna Kumar ◽  
V.K Tomar

Abstract This paper presents a single-ended read and differential write half select free 9T static random access memory (SRAM) cell operates in the sub-threshold region. Proposed 9T SRAM cell shows a reasonable reduction in read and write power dissipation by a factor of 1.41× and 2.1× respectively as of conventional 6T (Conv.6T) SRAM cell. The stacking of transistors at core latch network minimizes the leakage power of the cell. The read static noise margin (RSNM) and write margin (WM) are upgraded by 2.16× and 2.06× respectively as of Conv.6T cell. A forward body bias technique is utilized in read path which results to decreases in read access time by a factor of 2.72× as of standard 6T SRAM cell. The mean value of Ion/Ioff ratio of the proposed cell is improved by 2.92× as compared to the Conv.6T SRAM cell. It is attributed to a reduction in bit-line leakage current. To achieve more soundness in characteristics of the proposed 9T SRAM cell, process variation effect on RSNM, power dissipation, and read current is calculated through Monte Carlo (MC) simulation at 5000 points. The obtained results are compared with reference SRAM cells at 0.3V supply voltage.


2010 ◽  
Vol 19 (07) ◽  
pp. 1449-1464 ◽  
Author(s):  
BYUNGHEE CHOI ◽  
YOUNGSOO SHIN

A reduced supply voltage must be accompanied by a reduced threshold voltage, which makes this approach to power saving susceptible to process variation in transistor parameters, as well as resulting in increased subthreshold leakage. While adaptive body biasing is efficient for both compensating process variation and suppressing leakage current, it suffers from a large overhead of control circuit. Most body biasing circuits target an entire chip, which causes excessive leakage of some blocks and misses the chance of fine grain control. We propose a new adaptive body biasing scheme, based on a lookup table for independent control of multiple functional blocks on a chip, which controls leakage and also compensates for process variation at the block level. An adaptive body bias is applied to blocks in active mode and a large reverse body bias is applied to blocks in standby mode. This is achieved by a central body bias controller, which has a low overhead in terms of area, delay, and power consumption. The problem of optimizing the required set of bias voltages is formulated and solved. A design methodology for semicustom design using standard-cell elements is developed and verified with benchmark circuits.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1718
Author(s):  
Neha Gupta ◽  
Ambika Prasad Shah ◽  
Sajid Khan ◽  
Santosh Kumar Vishvakarma ◽  
Michael Waltl ◽  
...  

This paper proposes an error-tolerant reconfigurable VDD (R-VDD) scaled SRAM architecture, which significantly reduces the read and hold power using the supply voltage scaling technique. The data-dependent low-power 10T (D2LP10T) SRAM cell is used for the R-VDD scaled architecture with the improved stability and lower power consumption. The R-VDD scaled SRAM architecture is developed to avoid unessential read and hold power using VDD scaling. In this work, the cells are implemented and analyzed considering a technologically relevant 65 nm CMOS node. We analyze the failure probability during read, write, and hold mode, which shows that the proposed D2LP10T cell exhibits the lowest failure rate compared to other existing cells. Furthermore, the D2LP10T cell design offers 1.66×, 4.0×, and 1.15× higher write, read, and hold stability, respectively, as compared to the 6T cell. Moreover, leakage power, write power-delay-product (PDP), and read PDP has been reduced by 89.96%, 80.52%, and 59.80%, respectively, compared to the 6T SRAM cell at 0.4 V supply voltage. The functional improvement becomes even more apparent when the quality factor (QF) is evaluated, which is 458× higher for the proposed design than the 6T SRAM cell at 0.4 V supply voltage. A significant improvement of power dissipation, i.e., 46.07% and 74.55%, can also be observed for the R-VDD scaled architecture compared to the conventional array for the respective read and hold operation at 0.4 V supply voltage.


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