Mr.Wolf: An Energy-Precision Scalable Parallel Ultra Low Power SoC for IoT Edge Processing

This paper presents Mr. Wolf, a parallel ultra-low power (PULP) system on chip (SoC) featuring a hierarchical architecture with a small (12 kgates) microcontroller (MCU) class RISC-V core augmented with an autonomous IO subsystem for efficient data transfer from a wide set of peripherals. The small core can offload compute-intensive kernels to an eight-core floating-point capable of processing engine available on demand. The proposed SoC, implemented in a 40-nm LP CMOS technology, features a 108-mu W fully retentive memory (512 kB). The IO subsystem is capable of transferring up to 1.6 Gbit/s from external devices to the memory in less than 2.5 mW. The eight-core compute cluster achieves a peak performance of 850 million of 32-bit integer multiply and accumulate per second (MMAC/s) and 500 million of 32-bit floating-point multiply and accumulate per second (MFMAC/s) -1 GFlop/s-with an energy efficiency up to 15 MMAC/s/mW and 9 MFMAC/s/mW. These building blocks are supported by aggressive on-chip power conversion and management, enabling energy-proportional heterogeneous computing for always-on IoT end nodes improving performance by several orders of magnitude with respect to traditional single-core MCUs within a power envelope of 153 mW. We demonstrated the capabilities of the proposed SoC on a wide set of near-sensor processing kernels showing that Mr. Wolf can deliver performance up to 16.4 GOp/s with energy efficiency up to 274 MOp/s/mW on real-life applications, paving the way for always-on data analytics on high-bandwidth sensors at the edge of the Internet of Things

Fully Synthesizable Low-Area Digital-to-Analog Converter With Graceful Degradation and Dynamic Power-Resolution Scaling

In this paper, a fully synthesizable digital-to-analog converter (DAC) is proposed. Based on a digital standard cell approach, the proposed DAC allows very low design effort, enables digital-like shrinkage across CMOS generations, low area at down-scaled technologies, and operation down to near-threshold voltages. The proposed DAC can operate at supply voltages that are significantly lower and/or at clock frequencies that are significantly greater than the intended design point, at the expense of moderate resolution degradation. In a 12-bit 40-nm testchip, graceful degradation of 0.3bit/100mV is achieved when V_DD is over-scaled down to 0.8V, and 1.4bit/100mV when further scaled down to 0.6V. The proposed DAC enables dynamic power-resolution tradeoff with 3X (2X) power saving for 1-bit resolution degradation at iso-sample rate (iso-resolution). A 12-bit DAC testchip designed with a fully automated standard cell flow in 40nm consumes 55µW at 27kS/s (9.1µW at 13.5kS/s) at a compact area of 500µm^2 and low voltage of 0.55V

Standard Cell-Based Ultra-Compact DACs in 40-nm CMOS

In this paper, very compact, standard cell-based Digital-to-Analog converters (DACs) based on the Dyadic Digital Pulse Modulation (DDPM) are presented. As fundamental contribution, an optimal sampling condition is analytically derived to enhance DDPM conversion with inherent suppression of spurious harmonics. Operation under such optimal condition is experimentally demonstrated to assure resolution up to 16 bits, with 9.4–239X area reduction compared to prior art. The digital nature of the circuits also allows extremely low design effort in the order of 10 man-hours, portability across CMOS generations, and operation at the lowest supply voltage reported to date. The limitations of DDPM converters, the benefits of the optimal sampling condition and digital calibration were explored through the optimized design and the experimental characterization of two DACs with moderate and high resolution. The first is a general-purpose DAC for baseband signals achieving 12-bit (11.6 ENOB) resolution at 110kS/s sample rate and consuming $50.8\mu \text{W}$ , the second is a DAC for DC calibration achieving 16-bit resolution with 3.1-LSB INL, 2.5-LSB DNL, $45\mu \text{W}$ power, at only $530\mu \text{m}^{2}$ area

Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

Wideband vibration energy harvesting using electromagnetic transduction for powering internet of things

The ‘Internet of Things-(IoT)’ envisions a world scattered with physical sensors that collect and transmit data about almost anything and thereby enabling intelligent decision-making for a smart environment. While technological advancements have reduced the power consumption of such devices significantly, the problem of perpetual energy supply beyond the limited capability of batteries is a bottleneck to this vision which is yet to be resolved. This issue has surged the research to investigate the prospect of harvesting the energy out of ambient mechanical vibrations. However, limited applications of conventional resonant devices under most practical environments involving frequency varying inputs, has gushed the research on wideband transducers recently. To facilitate multi-frequency operation at low-frequency regime, design innovations of the Silicon-onInsulator based MEMS suspension systems are performed through multi-modal activation. For continuous bandwidth widening, the benefits of using nonlinear stiffness in the system dynamics are investigated. By topologically varying the spring architectures, dramatically improved operational bandwidth with large power-density is obtained, which is benchmarked using a novel figure-of-merit. However, the fundamental phenomenon of multi-stability limits many nonlinear oscillator based applications including energy harvesting. To address this, an electrical control mechanism is introduced which dramatically improves the energy conversion efficiency over a wide bandwidth in a frequencyamplitude varying environment using only a small energy budget. The underlying effects are independent of the device-scale and the transduction methods, and are explained using a modified Duffing oscillator model. One of the key requirements for fully integrated electromagnetic transducers is the CMOS compatible batch-fabrication of permanent magnets with large energy-product. In the final module of the works, nano-structured CoPtP hard-magnetic material with large coercivity is developed at room-temperature using a current modulated electro-deposition technique. The demagnetization fields of the magnetic structures are minimized through optimized micro-patterns which enable the full integration of high performance electromagnetic energy harvesters

Proceedings of the Scientific-Practical Conference "Research and Development - 2016"

talent management; sensor arrays; automatic speech recognition; dry separation technology; oil production; oil waste; laser technolog