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This paper presents a rectifier-less ac–dc energy harvesting circuit capable of harvesting energy from multiple low-voltage piezoelectric transducers (PETs). Synchronous electric charge extraction technique, with bidirectional switches, is adopted to achieve rectifier-less ac–dc direct conversion. The inductor is engaged only during the voltage peak of the PET output for a short period of time and therefore, a single inductor can be shared by multiple transducers. A split-capacitor charging topology is employed to harvest both positive and negative half-cycle energies, without the use of an input rectifier. In addition, a self-startup function is incorporated to kick-start the system from low input voltages. A prototype has been implemented with off-the-shelf components. Energy harvesting from three PET energy sources with different resonance frequencies is demonstrated. A peak overall power conversion efficiency of 79% is achieved with a system self-startup voltage of 650 mV. [ABSTRACT FROM AUTHOR]

In this paper, a six-port distributed model of on-chip single-turn transformers in silicon that can predict the features of the transformers up to 200 GHz is presented. Moreover, the proposed model is scalable with the diameter of the transformer. Based on the developed model, a transformer balun with improved differential-port balance is deployed in a D-band up-conversion mixer design in \ 0.13- \mu\ m SiGe BiCMOS technology. The mixer achieves a measured conversion gain (CG) of \4 \sim \ 7~\ dB and local-oscillator-to-RF isolation over 30 dB from 110 to 140 GHz. The results have one of the best CGs in the millimeter-wave range. A D-band two-stage transformer-coupled power amplifier (PA) integrated with a mixer is also reported here. Using the six-port transformer model, the performance of the PA can be conveniently optimized. At a 2-V supply, the gain and saturated output power of 20 dB and 8 dBm, respectively, are both experimentally achieved at 127 GHz. At 3 V, the measured output power rose to 11 dBm and this is the best power performance among the reported D-band silicon-based amplifiers to date. [ABSTRACT FROM AUTHOR]

This work discusses the design methodologies of 130-GHz high gain and high efficiency on-chip meander slot antennas in a standard CMOS technology. In the proposed structure, stacked dielectric resonators (DRs) are placed on the top of the on-chip feeding element to form series-fed antenna array for antenna gain and efficiency improvement. The integrated antenna with double stacked DRs achieved a measured gain of 4.7 dBi at 130 GHz with a bandwidth of 11%. The antenna size is 0.8\times 0.9\ mm^2 and the simulation results indicate a radiation efficiency of 43%. To the best of our knowledge, this is the first demonstration of an on-chip antenna gain and efficiency enhancement through stacked DRs. [ABSTRACT FROM PUBLISHER]

The scene text interpretation is a critical part of the natural scene interpretation. Currently, most of the existing work is based on high-end graphics processing units (GPUs) implementation, which is commonly used on the server side. However, in Internet of Things (IoT) application scenarios, the communication overhead from the edge device to the server is quite large, which sometimes even dominates the total processing time. Hence, the edge-computing oriented design is needed to solve this problem. In this paper, we present an architectural design and implementation of a natural scene text interpretation (NSTI) accelerator, which can classify and localize the text region on pixel-level efficiently in real-time on mobile devices. To target the real-time and low-latency processing, the binary convolutional encoder–decoder network is adopted as the core architecture to enable massive parallelism due to its binary feature. Massively parallelized computations and a highly pipelined data flow control enhance its latency and throughput performance. In addition, all the binarized intermediate results and parameters are stored on chip to eliminate the power consumption and latency overhead of the off-chip communication. The NSTI accelerator is implemented in a 40 nm CMOS technology, which can process scene text images (size of 128 × 32) at 34 fps and latency of 40 ms for pixelwise interpretation with the pixelwise classification accuracy over 90% on ICDAR-03 and ICDAR-13 dataset. The real energy-efficiency is 698 GOP/s/W and the peak energy-efficiency can get up to 7825 GOP/s/W. The proposed accelerator is 7 times more energy efficient than its optimized GPU-based implementation counterpart, while maintaining a real-time throughput with latency of 40 ms. [ABSTRACT FROM AUTHOR]

A dominant-pole substitution (DPS) technique for low-dropout regulator (LDO) is proposed in this paper. The DPS technique involves signal-current feedforward and amplification such that an ultralow-frequency zero is generated to cancel the dominant pole of LDO, while a higher frequency pole substitutes in and becomes the new dominant pole. With DPS, the loop bandwidth of the proposed LDO can be significantly extended, while a standard value and large output capacitor for transient purpose can still be used. The resultant LDO benefits from both the fast response time due to the wide loop bandwidth and the large charge reservoir from the output capacitor to achieve the significant enhancement in the dynamic performances. Implemented with a commercial 0.18-μm CMOS technology, the proposed LDO with DPS is validated to be capable of delivering 100 mA at 1.0-V output from a 1.2-V supply, with current efficiency of 99.86%. Experimental results also show that the error voltage at the output undergoing 100 mA of load transient in 10-ns edge time is about 25 mV. Line transient responses reveal that no more than 20-mV instantaneous changes at the output when the supply voltage swings between 1.2 and 1.8 V in 100 ns. The power-supply rejection ratio at 3 MHz is −47 dB. [ABSTRACT FROM AUTHOR]