Energy-efficient data retention in D flip-flops using STT-MTJ

Circuit World ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 229-241 ◽  
Author(s):  
Kanika Monga ◽  
Nitin Chaturvedi ◽  
S. Gurunarayanan

Purpose Emerging event-driven applications such as the internet-of-things requires an ultra-low power operation to prolong battery life. Shutting down non-functional block during standby mode is an efficient way to save power. However, it results in a loss of system state, and a considerable amount of energy is required to restore the system state. Conventional state retentive flip-flops have an “Always ON” circuitry, which results in large leakage power consumption, especially during long standby periods. Therefore, this paper aims to explore the emerging non-volatile memory element spin transfer torque-magnetic tunnel junction (STT-MTJ) as one the prospective candidate to obtain a low-power solution to state retention. Design/methodology/approach The conventional D flip-flop is modified by using STT-MTJ to incorporate non-volatility in slave latch. Two novel designs are proposed in this paper, which can store the data of a flip-flip into the MTJs before power off and restores after power on to resume the operation from pre-standby state. Findings A comparison of the proposed design with the conventional state retentive flip-flop shows 100 per cent reduction in leakage power during standby mode with 66-69 per cent active power and 55-64 per cent delay overhead. Also, a comparison with existing MTJ-based non-volatile flip-flop shows a reduction in energy consumption and area overhead. Furthermore, use of a fully depleted-silicon on insulator and fin field-effect transistor substituting a complementary metal oxide semiconductor results in 70-80 per cent reduction in the total power consumption. Originality/value Two novel state-retentive D flip-flops using STT-MTJ are proposed in this paper, which aims to obtain zero leakage power during standby mode.

Circuit World ◽  
2020 ◽  
Vol 46 (2) ◽  
pp. 93-105
Author(s):  
Neethu Anna Sabu ◽  
Batri K.

Purpose This paper aims to design three low-power and area-efficient serial input parallel output (SIPO) register designs, namely, transistor count reduction technique shift register (TCRSR), series stacking in TCR shift register (S-TCRSR) and forced stacking of transistor in TCR shift register (FST in TCRSR). Shift registers (SR) are the basic building blocks of all types of digital applications. The performance of all the designs has been improved through one of the metaheuristic algorithms named elephant herding optimization (EHO) algorithm and hence suited for low-power very large scale integration (VLSI) applications. It is for the first time that the EHO algorithm is implemented in memory elements. Design/methodology/approach The registers together with clock network consume 18-36 percentage of the total power consumption of a microprocessor. The proposed designs are implemented using low-power and high-performance double edge-triggered D flip-flops with least count of clocked transistors involving transmission gate. The second and third register designs are developed from the modified version of the first one employing series and forced stacking, thereby reducing static power because of sub-threshold leakage current. The performance parameters such as power-delay-product (PDP) and leakage power are further optimized using the EHO algorithm. A greater reduction in power is achieved in all the designs by utilizing the EHO algorithm. Findings All the designs are simulated at a supply voltage of 1 V/500 MHz when the input switching activity is 25 percentage in Cadence Virtuoso using 45 nm CMOS technology. Nine recently proposed SR designs are simulated in the same conditions, and the performance has been compared with the proposed ones. The simulated results prove the excellence of proposed designs in different performance parameters like leakage power, energy-delay-product (EDP), PDP, layout area compared with the recent designs. The PDPdq value has a reduction of 95.9per cent (TCRSR), 96.6per cent (S-TCRSR) and 97per cent (FST in TCRSR) with that of a conventional shift register (TGSR). Originality/value The performance of proposed low-power SR designs is enhanced using EHO algorithm. The optimized performance results have been compared with a few optimization algorithms. It is for the first time that EHO algorithm is implemented in memory elements.


Author(s):  
FAYAZ KHAN ◽  
SIREESH BABU

This paper enumerates design of D flip flop with low power and low area for low power applications, for that analysis of various D-flip flops for low power dissipation ,area and delays is carried out at 0.12um to achieve low power, low-area the technology is scaled down to nanometer ranges, due to shrinking process, the leakage power tends to play a vital role in total power consumption at nano meter technology. In this paper, different D flip flop circuits are designed using Berkeley Short Channel Insulated Gate MOSFET (BSIM4) model equations., in this paper to reduce leakage power at 90nm 70nm and 50nm we implement leakage power reduction techniques six techniques are considered they are namely Sleep transistor, sleepy stack, Dual sleep ,Dual stack Forced Transistor sleep (FTS) and Sleepy keeper From the results, it is observed that SLEEP TRANSISTOR, and SLEEPY KEEPER.FORCED TRANSISTOR SLEEP techniques produces lower power dissipation than the other techniques , in this paper a qualitative comparison is done with the help of Dsch,, Micro wind Simulation tools, this paper concludes that a leakage reduction technique produce different power optimization levels for different architectures and employing a suitable technique for a particular architecture will be an effective way of reducing the leakage current and thereby static power.


Author(s):  
Pooran Singh ◽  
Santosh Vishvakarma

An ultra-low power (ULP), power gated static random access memory (SRAM) is presented for Internet of Things (IoT) applications, which operates in sub-threshold voltage ranges from 300mV to 500mV. The proposed SRAM has tendency to operate in low supply voltages with high static and dynamic noise margins. The IoT application involves battery enabled low leakage memory architecture in subthreshold regime which has low power consumption. Therefore, to improve power consumption along with better cell stability, a power gated 10T SRAM is presented. The proposed cell uses a power gated p-MOS transistor to reduce the leakage power or static power in standby mode. Moreover, due to the schmitt triggering and read decoupling of 10T SRAM the static and dynamic behavior in read, write and standby mode has shown enhanced tolerance at different process, voltage and temperature (PVT) conditions. The proposed SRAM shows better results in terms of leakage power, read static noise margin (RSNM), write static noise margin (WSNM), write-ability or write trip point (WTP), read-write energy and dynamic read margin (DRM). Further, these parameters are observed at 8-Kilo bit (Kb) and compared with already existing SRAM architectures. It is observed that the leakage power is reduced by 1/81×, 1/75× of the conventional 6T (C6T) SRAM and read decoupled 8T (RD8T) SRAM, respectively at 300mV VDD. On the contrary, RSNM, WSNM, WTP and DRM values are improved by 3×, 2×, 11.11% and 31.8% as compared to C6T SRAM, respectively. Similarly, proposed 10T has 1.48×, 25% and 9.75% better RSNM, WSNM and WTP values as compared to RD8T SRAM, respectively at 300mV VDD.


2019 ◽  
Vol 9 (1) ◽  
pp. 3
Author(s):  
Lekbir Cherif ◽  
Mohamed Chentouf ◽  
Jalal Benallal ◽  
Mohammed Darmi ◽  
Rachid Elgouri ◽  
...  

Recently, the multi-bit flip-flop (MBFF) technique was introduced as a method for reducing the power consumption and chip area of integrated circuits (ICs) during the physical implementation stage of their development process. From the perspective of the consumer, the main requirements for such an optimization method are high performance, low power usage and small area (PPA). Therefore, any new optimization technique should improve at least one, if not all, of these requirements. This paper proposes a new low-power methodology, applying a MBFF merging solution during the physical implementation of an IC to achieve better power consumption and area reduction. The aim of this study is to prove the benefit of this methodology on the power saving capability of the system while demonstrating that the proposed methodology does not have a negative impact on the circuit performance and design routability. The experimental results show that MBFF merging of 76% can be achieved and preserved throughout the entire physical implementation process, from cell placement to the final interconnection routing, without impacting the system’s performance or routability. Moreover, the clock wirelength, nets and buffers needed to balance the clock network were reduced by 11.98%, 3.82% and 9.16%, respectively. The reduction of the clock tree elements led to a reduction of the power consumption of the clock nets, registers and cells by 22.11%, 20.84% and 12.38%, respectively. The total power consumption of the design was reduced by 2.67%.


2018 ◽  
Vol 15 (6) ◽  
pp. 792-803
Author(s):  
Sudhakar Jyothula

PurposeThe purpose of this paper is to design a low power clock gating technique using Galeor approach by assimilated with replica path pulse triggered flip flop (RP-PTFF).Design/methodology/approachIn the present scenario, the inclination of battery for portable devices has been increasing tremendously. Therefore, battery life has become an essential element for portable devices. To increase the battery life of portable devices such as communication devices, these have to be made with low power requirements. Hence, power consumption is one of the main issues in CMOS design. To reap a low-power battery with optimum delay constraints, a new methodology is proposed by using the advantages of a low leakage GALEOR approach. By integrating the proposed GALEOR technique with conventional PTFFs, a reduction in power consumption is achieved.FindingsThe design was implemented in mentor graphics EDA tools with 130 nm technology, and the proposed technique is compared with existing conventional PTFFs in terms of power consumption. The average power consumed by the proposed technique (RP-PTFF clock gating with the GALEOR technique) is reduced to 47 per cent compared to conventional PTFF for 100 per cent switching activity.Originality/valueThe study demonstrates that RP-PTFF with clock gating using the GALEOR approach is a design that is superior to the conventional PTFFs.


Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1429 ◽  
Author(s):  
Jin-Fa Lin ◽  
Cheng-Yu Chan ◽  
Shao-Wei Yu

In this paper, a novel latch-adder based multiplier design, targeting low voltage and low power IoT applications is presented. It employs a semi-dynamic (dynamic circuit with static keeper circuit) full adder design which efficiently incorporates the level sensitive latch circuit with the adder cell. Latch circuit control signals are generated by a chain of delay cell circuits. They are applied to each row of the adder array. This row-wise alignment ensures an orderly procedure, while successfully removing spurious switching resulting in reduced power consumption. Due to the delay cell circuit of our design is also realized by using full adder. Therefore, it is unnecessary to adjust the transistor sizes of the delay cell circuit deliberately. Post-layout simulation results on 8 × 8 multiplier design show that the proposed design has the lowest power consumption of all design candidates. The total power consumption saving compared to conventional array multiplier designs is up to 38.6%. The test chip measurement shows successful operations of our design down to 0.41 V with a power consumption of only 427 nW with a maximum frequency 500 KHz.


Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3649
Author(s):  
Minhyun Jin ◽  
Hyeonseob Noh ◽  
Minkyu Song ◽  
Soo Youn Kim

In this paper, we propose a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) that has built-in mask circuits to selectively capture either edge-detection images or normal 8-bit images for low-power computer vision applications. To detect the edges of images in the CIS, neighboring column data are compared in in-column memories after column-parallel analog-to-digital conversion with the proposed mask. The proposed built-in mask circuits are implemented in the CIS without a complex image signal processer to obtain edge images with high speed and low power consumption. According to the measurement results, edge images were successfully obtained with a maximum frame rate of 60 fps. A prototype sensor with 1920 × 1440 resolution was fabricated with a 90-nm 1-poly 5-metal CIS process. The area of the 4-shared 4T-active pixel sensor was 1.4 × 1.4 µm2, and the chip size was 5.15 × 5.15 mm2. The total power consumption was 9.4 mW at 60 fps with supply voltages of 3.3 V (analog), 2.8 V (pixel), and 1.2 V (digital).


1996 ◽  
Vol 07 (02) ◽  
pp. 305-322
Author(s):  
KAI-YUAN CHAO ◽  
D. F. WONG

In this paper, a floorplanner for low power design is presented. Our objective is to optimize total power consumption and area during the selection and placement of various implementations for circuit modules. Furthermore, the proposed method considers performance requirements, power line noises, and distribution of power consumption in order to generate lower and evenly distributed power dissipation over the resulting circuit floorplan with a specified performance. For a set of benchmark circuits we tested, on the average, our floorplanner can achieve decreases of total power consumption, wire-length, and power/ground network size by 18.3%, 4.6%, and 24%, respectively, at the cost of an area increase of 8.8% when compared with an existing area/wire-length driven floorplanner.


Integration ◽  
2018 ◽  
Vol 60 ◽  
pp. 160-166 ◽  
Author(s):  
Ahmad Karimi ◽  
Abdalhossein Rezai ◽  
Mohammad Mahdi Hajhashemkhani

2019 ◽  
Vol 25 (6) ◽  
pp. 35-39
Author(s):  
Libor Chrastecky ◽  
Jaromir Konecny ◽  
Martin Stankus ◽  
Michal Prauzek

This article describes implementation possibilities of specialized microcontroller peripherals, as hardware solution for Internet of Things (IoT) low-power communication, interfaces. In this contribution, authors use the NXP FlexIO periphery. Meanwhile, RFC1662 is used as a reference communication standard. Implementation of RFC1662 is performed by software and hardware approaches. The total power consumption is measured during experiments. In the result section, authors evaluate a time-consumption trade-off between the software approach running in Central Processing Unit (CPU) and hardware implementation using NXP FlexIO periphery. The results confirm that the hardware-based approach is effective in terms of power consumption. This method is applicable in IoT embedded devices.


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