222 results
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2. The Dickson Charge Pump as a Signal Amplifier.
- Author
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Ballo, Andrea, Grasso, Alfio Dario, and Palumbo, Gaetano
- Subjects
ON-chip charge pumps ,SWITCHED capacitor circuits ,DC-to-DC converters - Abstract
In this paper it is proposed and explored the use of the Dickson charge pump (CP) to amplify time-variant signals. The study has been carried out through a theoretical analysis that provides an in-depth comprehension of the behavioral equations and the main design metrics commonly used to evaluate the performance of amplifiers. Starting from the analytical models, we show the conditions upon which the CP can be modeled with an equivalent small signal circuit and can amplify a signal. Then, assuming the CP working in the widest operative conditions, small-signal, large-signal and noise analysis are carried out. The results have been validated by extensive simulations and measurements on a proof of concept using a 130 nm CMOS technology. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Series-Parallel Charge Pump Conditioning Circuits for Electrostatic Kinetic Energy Harvesting.
- Author
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Karami, Armine, Galayko, Dimitri, and Basset, Philippe
- Subjects
ELECTRIC circuits ,ON-chip charge pumps ,KINETIC energy - Abstract
This paper presents a new family of conditioning circuits used in electrostatic kinetic energy harvesters (e-KEHs), generalizing a previously reported conditioning circuit known as the Bennet's doubler. The proposed topology implements a conditioning scheme described by a rectangular charge-voltage cycle (QV-cycle) of tunable aspect ratio. These circuits show an exponential increase of the converted energy over operation time if studied in the sole electrical domain. The QV-cycle's aspect ratio can be set to values that were previously inaccessible with other exponential conditioning circuits. After a brief intuitive presentation of the new topology, its operation is rigorously analyzed and its dynamics are quantitatively derived in the electrical domain. In particular, the aspect ratio of the rectangular QV-cycle describing the biasing scheme of the transducer is expressed as a function of the circuit's parameters. Practical considerations about the use of the reported conditioning circuits in actual e-KEHs are also presented. These include a discussion on the applications of the proposed conditioning, a description of the effects of electrical nonidealities, and a proposition of an energy extracting interface. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
4. Fully-Integrated Reconfigurable Charge Pump With Two-Dimensional Frequency Modulation for Self-Powered Internet-of-Things Applications.
- Author
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Cheng, Hao-Chung, Tsai, Wen-Yuan, Chen, Po-Han, and Chen, Po-Hung
- Subjects
ON-chip charge pumps ,PHOTOVOLTAIC cells ,FREQUENCY changers ,LIGHT intensity ,LOGIC circuits - Abstract
In this paper, we propose a fully-integrated reconfigurable charge pump in a 0.18- $\mu \text{m}$ CMOS process; this converter is applicable for self-powered Internet-of-Things applications. The proposed charge pump uses a two-dimensional frequency modulation technique, which combines both the pulse-frequency modulation (PFM) and pulse-skip modulation (PSM) techniques. The PFM technique adjusts the operating frequency of the converter according to the variations in the load current, and the PSM technique regulates the output voltage. The proposed two-dimensional frequency modulation technique can improve the overall power conversion efficiency and the response time of the converter under light load conditions. A photovoltaic cell was chosen as the input source of the proposed converter. To adapt to the variations in the output voltage of a photovoltaic cell under different light illumination intensities, we built a reconfigurable converter core with multiple power conversion ratios of 2, 2.5, and 3 for the regulated output voltage of 1.2 V when the input voltage ranged from 0.53 V to 0.7 V. Our measurement results prove that the proposed capacitive power converter could achieve a peak power conversion efficiency of 80.8%, and the efficiency was more than 70% for the load current that ranged from $10~\mu \text{A}$ to $620~\mu \text{A}$. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
5. On the Stability of Charge-Pump Phase-Locked Loops.
- Author
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Homayoun, Aliakbar and Razavi, Behzad
- Subjects
ON-chip charge pumps ,LOOPS (Group theory) ,OSCILLATIONS ,ELECTRIC circuits ,ELECTRIC potential ,CAPACITORS - Abstract
This paper employs a time-variant model to determine the exact small-signal loop transmission of second-order charge-pump phased-locked loops. The model predicts that a loop bandwidth of close to half the input frequency can be achieved. The large-signal behavior is also analyzed and two modes of oscillation are identified. The results are confirmed by means of circuit simulations. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
6. An Optically-Powered 432 MHz Wireless Tag for Batteryless Internet-of-Things Applications.
- Author
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Cheng, Hao-Chung, Chen, Yen-Ting, Chen, Po-Hung, and Liao, Yu-Te
- Subjects
ON-chip charge pumps ,LIGHT ,PHASE-locked loops ,OPTICAL transmitters ,ENERGY harvesting - Abstract
This paper presents an optically-powered wireless tag, integrating a charge pump (CP) and a low-power RF transmitter for batteryless Internet-of-Things (IoT) applications. The proposed charge pump with hysteresis regulation mechanism (HRM) powers the transmitter circuit using indoor light energy. The charge pump enables the transmitter whenever the output capacitor stores sufficient energy and guarantees a short period signal transmission. The proposed low-power transmitter contains the subharmonically injection-locked PLL and the capacitive coupling technique to achieve a large frequency multiplication ratio. The proposed batteryless wireless chip is fabricated in 0.18- $\mu \text{m}$ CMOS process. The measurement results demonstrate that the proposed charge pump provides a 1.1 to 1.3 V hysteresis regulated voltage under indoor light illumination larger than 300 lux. The charge pump achieves 84.1% peak efficiency and the communication distance of 3 meters is demonstrated while only consuming $248~\mu \text{W}$. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
7. A Sub-10 mV Power Converter With Fully Integrated Self-Start, MPPT, and ZCS Control for Thermoelectric Energy Harvesting.
- Author
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Luo, Zhihong, Zeng, Lei, Lau, Benjamin, Lian, Yong, and Heng, Chun-Huat
- Subjects
MAXIMUM power point trackers ,ZERO current switching ,THERMOELECTRIC generator design & construction ,OSCILLATOR strengths ,COMPLEMENTARY metal oxide semiconductor performance - Abstract
An inductive power converter for thermoelectric generator (TEG) is presented in this paper. A novel redundant inverter ring oscillator is proposed to self-oscillate in a very low supply voltage down to 45 mV. An additional self-start assist circuit with a differential clock booster and an exponential charge pump is implemented in the power converter to achieve lower self-start voltage. Boundary continuous-conduction mode, zero current switch (ZCS), and maximum power point tracking (MPPT) features have been incorporated into the power converter. Selective turn-ON dynamical-comparators have been used in ZCS and MPPT circuits to save power and achieve minimum operating supply voltage. Fabricated in 65-nm CMOS process, the chip can self-start at 210 mV. After self-start, only 7-mV input voltage is needed to sustain the power converter operation. With a TEG open circuit voltage of 80 mV and internal resistance of $5~\Omega $ , the chip can provide a maximum output power of 229~\mu \text{W} with end-to-end efficiency of 71.5%. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
8. High-Efficiency Charge Pumps for Low-Power On-Chip Applications.
- Author
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Jiang, Xiaoxue, Yu, Xiaojian, Moez, Kambiz, Elliott, Duncan G., and Chen, Jie
- Subjects
ON-chip charge pumps ,CHARGE transfer ,COMPLEMENTARY metal oxide semiconductors - Abstract
This paper proposes charge pumps with improved power efficiency suitable for low-power on-chip applications. Undesired charge transfer, which has a direction opposite to that of the intended current flow, presents a significant source of power loss in charge pumps. The proposed charge pump circuit utilizes charge transfer switches with a complementary branch scheme to significantly reduce undesired charge transfer, thereby improving power efficiency and increasing output voltage effectively. An optimized gate control strategy is applied to further decrease the power loss caused by undesired charge transfer. Simulations of 8-stage charge pumps in a 0.13~\mu \textm standard CMOS technology show that for an input supply voltage of 1.2 V, the proposed charge pump circuit reaches a power efficiency of 58.72% with an output voltage of 7.45 V, when delivering 5-mA load current, and is able to maintain a power efficiency of around 50% and an output voltage of over 5 V as the load current increases to 10 mA. Compared with the other charge pump circuits, the simulation results demonstrate better performance of proposed charge pump circuits in terms of both voltage pumping gain and power efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
9. A Three-Stage Charge Pump With Forward Body Biasing in 28 nm UTBB FD-SOI CMOS.
- Author
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Pinheiro, Carlos A., Olivera, Fabian, and Petraglia, Antonio
- Subjects
ON-chip charge pumps ,SUPERCAPACITORS ,ENERGY harvesting ,STORAGE battery charging - Abstract
Energy harvesting techniques provide solutions for powering battery-free circuits or even for charging storage elements such as batteries or super capacitors. In this paper a self-starting switched-capacitor approach based on three-stage charge pump that is appropriate to thermoelectric and photo-voltaic energy harvesting, is carried out in a 28 nm ultra-thin buried oxide (UTBB) fully-depleted silicon-on-insulator (FD-SOI) CMOS technology. By taking advantage of the FD-SOI substrate characteristics, the forward-body-biasing (FBB) technique is applied in order to improve switch conductances. In addition, a sizing exploration of standard N-type and flipped-well P-type devices operating as switches is advanced, in order to provide optimum balance between their conductances. Extensive simulation results validate the proper operation of the charge pump at a minimum input voltage of 150 mV, and show a maximum efficiency peak of 63.3% at an input voltage of 350 mV and load a current of 500 nA. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
10. Nonlinear Analysis of Charge-Pump Phase-Locked Loop: The Hold-In and Pull-In Ranges.
- Author
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Kuznetsov, Nikolay, Matveev, Alexey, Yuldashev, Marat, and Yuldashev, Renat
- Subjects
PHASE-locked loops ,NONLINEAR analysis ,LIMIT cycles ,ON-chip charge pumps ,VOLTAGE-controlled oscillators - Abstract
In this paper a fairly complete mathematical model of CP-PLL, which reliable enough to serve as a tool for credible analysis of dynamical properties of these circuits, is studied. We refine relevant mathematical definitions of the hold-in and pull-in ranges related to the local and global stability. Stability analysis of the steady state for the charge-pump phase locked loop is non-trivial: straight-forward linearization of available CP-PLL models may lead to incorrect conclusions, because the system is not smooth near the steady state and may experience overload. In this work necessary details for local stability analysis are presented and the hold-in range is computed. An upper estimate of the pull-in range is obtained via the analysis of limit cycles. The study provided an answer to Gardner’s conjecture on the similarity of transient responses of CP-PLL and equivalent classical PLL and to conjectures on the infinite pull-in range of CP-PLL with proportionally-integrating filter. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
11. A Column-Parallel Inverter-Based Cyclic ADC for CMOS Image Sensor With Capacitance and Clock Scaling.
- Author
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Tang, Fang, Wang, Bo, Bermak, Amine, Zhou, Xichuan, Hu, Shengdong, and He, Xiaoyong
- Subjects
IMAGE sensors ,PHOTOELECTRIC devices ,COMPLEMENTARY metal oxide semiconductors ,CMOS image sensors ,DIGITAL images ,CMOS integrated circuits ,METAL oxide semiconductors - Abstract
This paper presents a low-power column-parallel inverter-based cyclic analog-to-digital converter (ADC) for CMOS image sensor readout circuit. By partially floating the capacitors inside the multiply digital-analog-converter during the least significant bit (LSB) quantization, the amplifier load capacitance could be significantly scaled down, which allows much higher settling speed and shorter cycle period. Since the signal-to-noise ratio for LSB cycle is relaxed due to the residual amplification, the proposed capacitance scaling only contributes ignorable input-referred quantization noise. Using the proposed techniques, a cyclic ADC can operate under 50% power consumption without suffering conversion rate, noise performance, and linearity. A 12-b quantization resolution test chip is fabricated using the TSMC 0.18- \mu \textm technology with 110 column-parallel ADC channels and 10.08- \mu \textm \times 750 - \mu \textm column pitch. The 3.5/−2 LSBs integral nonlinearity and 10.1-b effective-number-of-bit are measured under 2- \mu \texts sampling rate with 120- \mu \textW power consumption per channel. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
12. A Regulated Charge Pump for Tunneling Floating-Gate Transistors.
- Author
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Rumberg, Brandon, Graham, David W., and Navidi, Mir Mohammad
- Subjects
ON-chip charge pumps ,CMOS integrated circuits ,TUNNEL design & construction - Abstract
Flash memory is an important component in many embedded system-on-a-chip applications, which drives the need to generate high write/erase voltages in generic CMOS processes. In this paper, we present a regulated, high-voltage charge pump for erasing Flash memory and floating-gate transistors. This 0.069-mm2 charge pump was fabricated in a 0.35 \mu \text m standard CMOS process. While operating from a 2.5 V supply, the charge pump generates regulated voltages up to 16 V with a PSRR of 52 dB and an output impedance of 6.8 \textk\Omega . To reduce power consumption for use in battery-powered applications, this charge pump uses a variable-frequency regulation technique and a new circuit for minimizing short-circuit current in the clock-generation circuitry; the resulting charge pump is able to erase the charge on floating-gate transistors using only $1.45 \mu J$ . [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Systematic Co-Design of Matching Networks and Rectifiers for CMOS Radio Frequency Energy Harvesters.
- Author
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Karami, Mohammad Amin and Moez, Kambiz
- Subjects
RADIO frequency ,ON-chip charge pumps ,ENERGY harvesting ,POLITICAL succession ,RADIO networks - Abstract
This paper presents a systematic methodology for the co-design of matching network and rectifier of radio frequency (RF) harvesters that results in maximum power conversion efficiency (PCE) for a given available power. This method is based on our newly developed rectifier model capable of calculating the CMOS Dickson’s rectifier’s input/output voltages at a given input power developed for low/high input power regimes. The proposed model allows for the co-design of the matching network and the rectifier in a fraction of time that takes for the design of the RF energy harvester using previously developed models relying on the knowledge of rectifier’s input voltage levels where a computationally extensive iterative design procedure must be performed because of the interdependence of the rectifier’s input voltage, the input power, and the matching network’s and rectifier’s parameters. The proposed methodology is capable of accurately predicting matching network components’ sizes for both the lossless and lossy matching networks for a maximum power transfer. Utilizing the proposed methodology, the designers can produce efficiency contour plots for a given input power for finding the optimum matching network and rectifier’s parameters for maximum PCE. The model, simulation, and measurement results for different parameters and input power levels in a 130-nm process are in good agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
14. A 60 mV Input Voltage, Process Tolerant Start-Up System for Thermoelectric Energy Harvesting.
- Author
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Dezyani, Mohammadjavad, Ghafoorifard, Hassan, Sheikhaei, Samad, and Serdijn, Wouter A.
- Subjects
ELECTRIC potential ,THERMOELECTRICITY ,ENERGY harvesting - Abstract
This paper presents a 60 mV input voltage start-up system for thermoelectric energy harvesting. A new process tolerant inverter cell is proposed, which is functional at supply voltages as low as 60 mV. Using the proposed unit cell, a ring oscillator has been implemented. The ring oscillator is followed by 40 charge-pump stages, an ultra-low-power level detector, and a boost converter. The energy harvesting system can generate an output voltage of 1 V and delivers a maximum power of $4.5~\mu \text{W}$ from a 60 mV supply. This system has been implemented in a standard $0.18~\mu \text{m}$ CMOS technology, uses neither zero-threshold voltage (normally-on) negative-channel metal-oxide semiconductor nor microelectromechanical systems switches and occupies 3.3 mm2. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
15. Study and Analysis of Pulsating and Nonpulsating Input and Output Current of Ultrahigh-Voltage Gain Hybrid DC–DC Converters.
- Author
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Andrade, Antonio Manuel Santos Spencer and Martins, Mario Lucio da Silva
- Subjects
VOLTAGE multipliers ,CAPACITOR switching ,ON-chip charge pumps ,DC-to-DC converters ,CASCADE converters - Abstract
In this paper, eight ultrahigh-voltage gain dc–dc converters are proposed. These sets of converters are derived by the association of boost cells, coupled inductor, voltage multiplier, switched capacitors, and LC filter cells. The nonpulsating input and output converters are evaluated in terms of: principle of operation, voltage gain, voltage and current stress, estimated power losses, and efficiency. Following full analysis prototypes built in the laboratory show experimental results verifying the theoretical analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
16. A Novel Integrated Step-Up Hybrid Converter With Wide Conversion Ratio.
- Author
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Marconi, Stefano, Spiazzi, Giorgio, Bevilacqua, Andrea, and Galvano, Maurizio
- Subjects
ON-chip charge pumps ,LIGHT emitting diodes ,ELECTRIC network topology - Abstract
In this paper, a novel topology combining reconfigurability and hybridization is presented. Reconfigurability allows the proposed converter to operate in three different operating modes, yielding a wide range of step-up conversion ratios. The combination of two charge-pump cells and an inductor allows to reduce the average inductor current if compared to a standard equivalent boost converter. A prototype with integrated MOS, drivers, and logic but external passives was built. Experimental results show that with $\mathbf {f_{s} }=\text{300}\,$ kHz, $\mathbf {V_{in} = \text{6}}\,$ V, and $\mathbf {I_o = \text{70}}\,$ mA, the converter can cover conversion ratios in the range from $\text {2.5}$ to $\text {10}$ , with a maximum output voltage equal to $\text {60}\,$ V. Peak efficiency is $\text {91}$ %. When the output current is increased to $\text {100}\,$ mA peak efficiency is $\text {92.8}$ %. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
17. A Hybrid Cockcroft–Walton/Dickson Multiplier for High Voltage Generation.
- Author
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Park, Sanghyeon, Yang, Jun, and Rivas-Davila, Juan
- Subjects
VOLTAGE multipliers ,ON-chip charge pumps ,ELECTRIC potential ,SWITCHED capacitor circuits ,LOW voltage systems ,HIGH voltages ,TRIBOELECTRICITY - Abstract
This paper presents a voltage multiplier topology that is a hybrid between a Cockcroft–Walton multiplier and a Dickson charge pump. The Cockcroft–Walton structure exhibits significant output voltage drop under load as the number of multiplier stage increases. This is because all coupling capacitors are connected in series. Dickson charge pump mitigates this issue by connecting all capacitors in parallel. But this solution comes at the expense of large capacitor voltage stress at the last multiplier stage. The proposed hybrid structure arranges some capacitors in parallel and others in series, thereby achieving low output voltage drop and low capacitor voltage stress at the same time. We develop a model that predicts hybrid multiplier's performance and validates it experimentally. We also demonstrate a 60–2.25 kV dc–dc converter based on a 16-stage hybrid voltage multiplier which achieves a voltage gain of 12.8 while keeping the highest capacitor voltage stress to 660 V. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
18. A 2.45-GHz Rectifier-Booster Regulator With Impedance Matching Converters for Wireless Energy Harvesting.
- Author
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Fan, Shiquan, Yuan, Zheyi, Gou, Wei, Zhao, Yang, Song, Chaoyun, Huang, Yi, Zhou, Jiafeng, and Geng, Li
- Subjects
ENERGY harvesting ,IMPEDANCE matching ,ON-chip charge pumps ,ELECTROMAGNETIC waves ,TRANSMITTING antennas ,DIPOLE antennas - Abstract
In this paper, a proof-of-concept high-efficiency rectifier-booster regulator (RBR) with an impedance matching converter operating at 2.45 GHz is proposed. An entire WLAN energy harvesting system is demonstrated. A flower-shaped broadband dual-polarized cross dipole antenna with a full-wave matching network is employed to harvest electromagnetic energy from a WiFi router. A novel RBR is proposed to rectify the RF energy to dc and boost the output voltage. It is evolved from a Greinacher rectifier and two Cockcroft–Walton charge pumps to form a full-wave rectifier. An equivalent resistance model is established to evaluate the optimal stage of the RBR. Furthermore, a boost converter is designed as an impedance matching converter to harvest as much energy as possible from the RBR and store the energy into a 1-mF supercapacitor. Experimental results show that the RBR can provide 1.7-V output voltage under −10-dBm input power. In addition, the RBR can achieve up to $\times 3.4$ voltage boosting with 85% voltage conversion rate (VCR) and provide a higher than 1-V output voltage within a distance of 50 cm between an antenna with 20-dBm transmitting power and the rectenna. The excellent performance shows the wide practicality of the proposed design method for the Internet-of-Things (IoT) applications. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
19. Study on 5.8-GHz Single-Stage Charge Pump Rectifier for Internal Wireless System of Satellite.
- Author
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Wang, Ce, Shinohara, Naoki, and Mitani, Tomohiko
- Subjects
WIRELESS communications ,ON-chip charge pumps ,HARMONIC analysis (Mathematics) ,CAPACITORS ,HARMONIC suppression filters - Abstract
To reduce the weight of a satellite, an internal wireless system (IWS) for satellites was proposed in a previous study. It is a system that can communicate between the satellite’s subsystems by using wireless communication modules. In this paper, we propose a complete IWS for a satellite using microwave wireless power transmission technology. The design of a 5.8-GHz high efficiency rectifier circuit-based charge pump circuit is also presented. Furthermore, we introduced a class-F load that can process the third harmonic components. The rectifying efficiencies of a normal charge pump rectifier and a charge pump rectifier with the class-F load are theoretically compared. To improve the conversion efficiency of the charge pump rectifier, the applied voltages of diodes are adjusted. Owing to inserting the class-F load and adjusted the applied voltage of diodes in this circuit, the conversion efficiency of the charge pump circuit at 30 mW increases to about 78% at 30 mW in the simulation, and to about 71% conversion efficiency in the experiment. In addition, the output voltage is higher than 5 V at an optimal load 1300 $\Omega $ . [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
20. Analysis of Voltage Doubler Behavior of 2.45-GHz Voltage Doubler-Type Rectenna.
- Author
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Mitani, Tomohiko, Kawashima, Shogo, and Nishimura, Taiga
- Subjects
VOLTAGE doublers ,RECTENNAS ,CAPACITORS ,ELECTRIC lines ,MICROWAVE measurements ,DIPOLE antennas ,INTEGRATED circuits - Abstract
This paper describes the voltage doubler (VD) behavior of a 2.45-GHz VD-type rectenna. An important feature of the developed VD-type rectenna is the absence of the charge pump capacitor that is present in conventional VDs. Based on the circuit simulation and measurement results, the developed VD-type rectenna shows drastic improvement to the radio frequency-to-direct current (RF–dc) conversion efficiency in comparison with a half-wave rectifier (HWR)-type rectenna at output loads exceeding $100~\Omega $ . From the simulation, both the VD- and HWR-type rectennas show VD behavior, even without the charge pump capacitor. This behavior was found to be attributable to the electric charge stored in the junction and package capacitances of the Schottky barrier diode in the rectennas. Additionally, it was found that the improvement of the RF–dc conversion efficiency is caused by the voltage conservation in the series diode. This improvement is dependent on the microwave period and the electric discharge time constant. When the microwave period is comparable with the electric discharge time constant, the VD-type rectenna conserves a dc voltage even when the input microwave voltage is negative. These phenomena were observed by analyzing the voltage and current waveforms of the rectenna equivalent circuit obtained via circuit simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
21. Analysis and Design of a Thermoelectric Energy Harvesting System With Reconfigurable Array of Thermoelectric Generators for IoT Applications.
- Author
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Wan, Qiping, Gao, Yuan, Mok, Philip K. T., and Teh, Ying-Khai
- Subjects
ENERGY harvesting ,THERMOELECTRIC generators ,INTERNET of things ,EQUIPMENT & supplies - Abstract
In this paper, a novel thermoelectric energy harvesting system with a reconfigurable array of thermoelectric generators (TEGs), which requires neither an inductor nor a flying capacitor, is proposed. The proposed architecture can accomplish maximum power point tracking (MPPT) and voltage conversion simultaneously via the reconfiguration of the TEG array, and demonstrate significantly improved power conversion efficiency over the conventional switching converter and switched-capacitor architectures. Two systematical scaling approaches—powers-of-two scaling and maximum-factor scaling—are presented and analyzed to serve as the design guideline, catering for reconfigurable TEG arrays of different sizes. In order to optimize the chip area required, a custom-designed, multi-level hierarchy and systematically scalable switch array that requires a reasonable number of switches is also developed to enable the reconfiguration of the TEG array. The 16-node and 12-node versions of the proposed system have been implemented in a standard 0.35- \mu \textm CMOS process. Measurement results verify the analysis, and confirm that the proposed system can maintain a higher than 88.8% efficiency over a wide range of temperature gradients. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
22. Compressed Level Crossing Sampling for Ultra-Low Power IoT Devices.
- Author
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Zhou, Jun, Zavareh, Amir Tofighi, Gupta, Robin, Silva-Martinez, Jose, Hoyos, Sebastian, Liu, Liang, Wang, Zhongfeng, and Sadler, Brian M.
- Subjects
INTERNET of things ,STATISTICAL sampling ,COMPRESSED sensing ,EQUIPMENT & supplies - Abstract
Level crossing sampling (LCS) is a power-efficient analog-to-digital conversion scheme for spikelike signals that arise in many Internet of Things-enabled automotive and environmental monitoring applications. However, LCS scheme requires a dedicated time-to-digital converter with large dynamic range specifications. In this paper, we present a compressed LCS that exploits the signal sparsity in the time domain. At the compressed sampling stage, a continuous-time ternary encoding scheme converts the amplitude variations into a ternary timing signal that is captured in a digital random sampler. At the reconstruction stage, a low-complexity split-projection least squares (SPLSs) signal reconstruction algorithm is presented. The SPLS splits random projections and utilizes a standard least squares approach that exploits the ternary-valued amplitude distribution. The SPLS algorithm is hardware friendly, can be run in parallel, and incorporates a low-cost k-term approximation scheme for matrix inversion. The SPLS hardware is analyzed, designed, and implemented in FPGA, achieving the highest data throughput and the power efficiency compared with the prior arts. Simulations of the proposed sampler in an automotive collision warning system demonstrate that the proposed compressed LCS can be very power efficient and robust to wireless interference, while achieving an approximately eightfold data volume compression when compared with Nyquist sampling approaches. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
23. On-Chip Solar Energy Harvester and PMU With Cold Start-Up and Regulated Output Voltage for Biomedical Applications.
- Author
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Cabello, Diego, Ferro, Esteban, Pereira-Rial, Oscar, Martinez-Vazquez, Beatriz, Brea, Victor M., Carrillo, Juan M., and Lopez, Paula
- Subjects
SOLAR energy ,ON-chip charge pumps ,ENERGY harvesting ,VOLTAGE regulators ,SOLAR cells ,PHASOR measurement ,ELECTRIC potential ,HARVESTING - Abstract
This paper presents experimental results from a system that comprises a fully autonomous energy harvester with a solar cell of 1 mm2 as energy transducer and a Power Management Unit (PMU) on the same silicon substrate, and an output voltage regulator. Both chips are implemented in standard $0.18~\mu \text{m}$ CMOS technology with total layout areas of 1.575 mm2 and 0.0126 mm2, respectively. The system also contains an off-the-shelf 3.2 mm $\times2.5$ mm $\times0.9$ mm supercapacitor working as an off-chip battery or energy reservoir between the PMU and the voltage regulator. Experimental results show that the fast energy recovery of the on-chip solar cell and PMU permits the system to replenish the supercapacitor with enough charge as to sustain Bluetooth Low Energy (BLE) communications even with input light powers of 510 nW. The whole system is able to self-start-up without external mechanisms at 340 nW. This work is the first step towards a self-supplied sensor node with processing and communication capabilities. The small form factor and ultra-low power consumption of the system components is in compliance with biomedical applications requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
24. A Switched Capacitor Multiple Input Single Output Energy Harvester (Solar + Piezo) Achieving 74.6% Efficiency With Simultaneous MPPT.
- Author
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Devaraj, Abhishekh, Megahed, Mohamed, Liu, Yutao, Ramachandran, Ashwin, and Anand, Tejasvi
- Subjects
CAPACITOR switching ,MAXIMUM power point trackers ,ON-chip charge pumps ,TRACKING algorithms ,DC-to-DC converters - Abstract
This paper presents an inductor-less switched capacitor based energy harvester, which can simultaneously harvest from 2 energy sources (Solar + Piezo). The proposed harvester employs maximum power point tracking algorithm, by changing the conversion ratios of the charge pumps for piezo and solar sources, and output voltage control by varying the switching frequency. The proposed MPPT algorithm can match the input impedance of two sources simultaneously. Implemented in 65nm CMOS, the proposed harvester can generate a fixed output between 1.8 and 2.5 V output while delivering 35 $\mu \text{W}$ to 70 $\mu \text{W}$ power with a peak power conversion efficiency of 74.6%. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
25. A Low-Noise, Positive-Input, Negative-Output Voltage Generator for Low-to-Moderate Driving Capacity Applications.
- Author
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Khanna, Devrishi, Boon, Chirn Chye, Choi, Pilsoon, Siek, Liter, Liu, Bei, and Li, Chenyang
- Subjects
GALLIUM nitride ,ELECTRIC potential ,POWER amplifiers ,TRIBOELECTRICITY ,ON-chip charge pumps ,VOLTAGE control ,PATTERN matching - Abstract
In this paper, a generic, low-noise, negative-voltage generator with wide tuning range and moderate driving capacity is presented. The highly integrated solution, incorporating a fully-integrated charge-pump and a regulator block, requires only one off-chip capacitor that can be shared with the supply decoupling capacitors. The fully integrated charge-pump operation is analyzed quantitatively, and a closed-form expression of its output impedance is derived. Powered from a single 3.3-V dc input, the output has a tuning range from −4.4 to +2.1 V for biasing applications, while the design supports a maximum load current of 250, 550, and $800~\mu \text{A}$ for the regulated output voltage at −3.0, −1.5, and 1.5 V, respectively. The measured steady-state ripple is under 3 mVPP, while the noise voltage at the charge-pump operating frequency harmonics is below 130 $\mu \text {V}_{\mathrm{ rms}}$ and the noise floor is under $5~\mu \text {V}_{\mathrm{ rms}}$. The design is also the application verified with a gallium nitride power amplifier, thus further confirming its low-noise performance. Implemented in CMOS 180-nm process, the prototype chip occupies an area of 0.55 mm2. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Micro-Energy Harvesting System Including a PMU and a Solar Cell on the Same Substrate With Cold Startup From 2.38 nW and Input Power Range up to 10 $\mu$W Using Continuous MPPT.
- Author
-
Ferro, Esteban, Brea, Victor Manuel, Lopez, Paula, and Cabello, Diego
- Subjects
ON-chip charge pumps ,SOLAR cells ,RELAXATION oscillators ,SILICON solar cells ,PHASOR measurement ,ENERGY harvesting - Abstract
This paper presents a power management unit (PMU) powered by a 1 mm $^{\boldsymbol{2}}$ solar cell on the same substrate to rise up the harvested voltage above 1.1 V. The on-chip solar cell and the PMU are fabricated in standard 0.18 $\mu$ m CMOS technology achieving a form factor of 1.575 mm $^{\boldsymbol{2}}$. The PMU is able to startup from a harvested power of 2.38 nW without any external kick off or control signal. The PMU features a continuous and two-dimensional maximum power point tracking (MPPT) working in open-loop mode to handle a harvested power range from nW to $\mu$ W, by modifying both the charge pump topology and the switching frequency. The MPPT is based on four voltage level detectors that define five working regions depending on the illumination and on a self-tuning reference current for a fine adjustment of the switching frequency. The chip also includes an auxiliary charge pump to generate the voltage level necessary for the control circuit, implemented as a Pelliconi charge pump of eight stages with NMOS transistors in P-well as diodes. A Dickson charge pump with transmission gates as switches and with variable gain and capacitance per stage is also designed as the main charge pump. Finally, two relaxation oscillators are implemented to drive both charge pumps. This paper is accompanied by a video file demonstrating the PMU operation by powering an off-chip nor gate. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Dual Switches DC/DC Converter With Three-Winding-Coupled Inductor and Charge Pump.
- Author
-
Tang, Yu, Fu, Dongjin, Kan, Jiarong, and Wang, Ting
- Subjects
ELECTRIC switchgear ,DC-to-DC converters ,ELECTRIC windings ,ELECTRIC inductors ,ON-chip charge pumps - Abstract
In order to obtain a high step-up voltage gain, high-efficiency converter, this paper proposed a dual switches dc/dc converter with three-winding-coupled inductor and charge pump. The proposed converter composed of dual switches structure, three-winding-coupled inductor, and charge pump. This combination facilitates realization of high step-up voltage gain with a low voltage/current stress on the power switches. Meanwhile, the voltage across the diodes is low and the diode reverse-recovery problem is alleviated by the leakage inductance of the three-winding-coupled inductor. Taking all these into consideration, the efficiency can be high. This paper illustrated the operation principle of the proposed converter; discussed the effect of leakage inductance on voltage gain; the conditions of zero current shutting off of the diodes are illustrated; the voltage and current stress of the power devices are shown; a comparison between the performance of the proposed converter and previous high step-up converters was conducted. Finally, a prototype rated at 500 W has been established, and the experimental results verify the correctness of the analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. A High Efficiency Orthogonally Switching Passive Charge Pump Rectifier for Energy Harvesters.
- Author
-
Mansano, Andre, Bagga, Sumit, and Serdijn, Wouter
- Subjects
ELECTRIC current rectifiers ,ENERGY harvesting ,ON-chip charge pumps ,COMPLEMENTARY metal oxide semiconductors ,TRANSISTORS ,SWITCHING circuits - Abstract
The design and analytical modeling of a high efficiency energy harvester comprising a passive voltage-boosting network (VBN) and a switching charge pump rectifier (CPR) is presented in this paper. To improve the power conversion efficiency (PCE), the VBN increases the voltage at the input of the CPR and provides control signals for switching. Unlike traditional Schottky and diode-connected MOS transistor rectifiers, the proposed orthogonally switching CPR (OS-CPR) comprises MOS transistors as voltage-controlled switches. Analytical models for the OS-CPR are developed and presented. Circuit-level optimization techniques are employed to reduce conduction and switching losses. Simulated in a 90 nm standard CMOS technology (IBM 9RF), a 5-stage 915 MHz OS-CPR achieves a dc voltage of 1.35 V and a PCE of 11.9% with a 1 M\Omega load at -18.2 dBm available input power (PS,AV). To show technology scalability of the design, the OS-CPR is also validated using AMS 0.18 \mum high-voltage (HV) CMOS technology. When benchmarked with traditional rectifiers, the OS-CPR (under similar conditions) achieves a higher PCE and a higher output dc voltage. The OS-CPR is easily scalable to operate over multiple sub-GHz ISM frequency bands. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
29. A 39.5-dB SNR, 300-Hz Frame-Rate, 56 ? 70-Channel Read-Out IC for Electromagnetic Resonance Touch Panels.
- Author
-
Kim, SangYun, Cho, SungHun, Pu, YoungGun, Hwang, Keum Cheol, Yang, Youngoo, Lee, Kang-Yoon, Yoo, Sang-Sun, and Lee, Minjae
- Subjects
ELECTROMAGNETIC devices ,TOUCH screens ,ON-chip charge pumps ,SIGNAL-to-noise ratio ,LOWPASS electric filters ,ANALOG-to-digital converters - Abstract
In this paper, a pen detection analog system for an electromagnetic resonance (EMR) touch panel is presented. An adaptive charge pump is proposed in the transmitter to drive a high current to the EMR panel and achieve a high signal-to-noise ratio (SNR) in the receiver. To compensate for the mismatches between the channels due to fabrication variations of the EMR panels and process variations of the analog front-ends (AFEs), a transmitter driver with an adaptive controller is proposed, and an AFE calibration is implemented in the transmitter and the receiver, respectively. Also, a 9-bit, 2-MS/s time-interleaved flash successive-approximation-register (SAR) analog-to-digital converter (ADC) with 3-bit flash and 6-bit SAR ADCs is proposed to increase the frame rate with small area and power consumption. External noises, such as display and charger noises, can be rejected by the differential processing, analog low-pass filter, and digital filters in the digital signal processor (DSP). This read-out integrated circuit is implemented in a 0.18-μm Bipolar-CMOS-DMOS (BCD), and the die area is \text40 mm^\text2 including DSP and ADCs. The power consumptions are 110 and 45 mW in the transmitter and receiver modes, respectively. The SNR is about 39.5 dB and the frame rate is about 300 Hz in the 56 × 70 touch panel. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
30. Event Driven Modeling and Characterization of the Second Order Voltage Switched Charge Pump PLL.
- Author
-
Ali, Ehsan, Hangmann, Christian, Hedayat, Christian, Haddad, Fayrouz, Rahajandraibe, Wenceslas, and Hilleringmann, Ulrich
- Subjects
ON-chip charge pumps ,PHASE-locked loops ,FREQUENCY discriminators ,PULSE width modulation ,IDEAL sources (Electric circuits) ,ELECTRICAL load ,ELECTRIC filters - Abstract
The charge pump phase locked loop (CP-PLL) is widely used subsystem in modern mixed-signal electronic systems that are utilized in digital and wireless applications such as clock generation, synchronization and frequency synthesis. In the classical mode, the combination of a current switched charge pump and a digital phase and frequency detector (CP-PFD) circuits produces an ideal pulse width modulated constant current during one sampling period, which permits a suitable transient performance. Nevertheless, many commercially used CP-PLL chips (e.g., 4046 family) have a voltage switched charge pump (VSCP) because the design of the constant voltage source is easier than the constant current generator and it is a low cost solution. However, the VSCP delivers a non-constant pump current, which varies during one sampling period related to the electrical load of the loop filter (LF). This effect results in a varying gain of the control system affecting significantly its tracking ability. Furthermore, due to its hybrid structure, the simulation of the CP-PLL at high frequencies is challenging and the analysis of its transient characteristics during its non-linear acquisition procedure is not easy. In this paper, a first ever exact and nonlinear model based on the phase equations of the second order voltage switched charge pump phase locked loop (VSCP-PLL) is established by using an event driven (ED) technique. This exact model is then simplified by using a step-wise quasi-constant current approximation during one sampling period to obtain the analytical phase equations. The derived ED-model is validated at transistor level simulations using 130 nm CMOS process. Furthermore, some typical nonlinear features of the VSCP-PLL are explored and the developed ED-models are compared with the quasi-time-continuous (QTC) theory. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
31. Capacitive Energy Conversion With Circuits Implementing a Rectangular Charge-Voltage Cycle—Part 1: Analysis of the Electrical Domain.
- Author
-
Galayko, Dimitri, Dudka, Andrii, Karami, Armine, O'Riordan, Eoghan, Blokhina, Elena, Feely, Orla, and Basset, Philippe
- Subjects
ELECTRIC power conversion ,ELECTRIC potential ,ELECTRIC charge ,ENERGY harvesting ,CAPACITORS ,EQUIPMENT & supplies - Abstract
Capacitive kinetic energy harvesters (KEH) employ conditioning circuits which achieve a dynamic biasing of the transducer's variable capacitor. This paper, composed of two articles Part 1 and Part 2, proposes a unified theory describing electrical and electromechanical properties of an important and wide class of conditioning circuits: those implementing a rectangular charge-voltage cycle. The article Part 1 introduces a basic configuration of conditioning circuit implementing an ideal rectangular QV cycle, and discusses its known practical implementations: the Roundy charge pump with different flyback mechanisms, and configurations based on the Bennet's doubler. In Part 1, the analysis is done in the electrical domain, without accounting for electromechanical coupling, while in Part 2, the full electromechanical system is analyzed. An optimization approach common to all configurations is proposed. A comparison is made between different topologies and operation modes, based on the maximal energy converted in one cycle under similar electrical and mechanical conditions. The last section discusses practical implementation of circuits with smart and adaptive behavior, and presents experimental results obtained with state-of-the art MEMS capacitive KEH devices. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
32. RAMSES: RFID Augmented Module for Smart Environmental Sensing.
- Author
-
De Donno, Danilo, Catarinucci, Luca, and Tarricone, Luciano
- Subjects
RADIO frequency identification systems ,REMOTE sensing ,SILICON-on-insulator technology ,DETECTORS ,ELECTRONIC circuits - Abstract
This paper presents a radio frequency identification (RFID) augmented module for smart environmental sensing (RAMSES), which is a fully passive device with sensing and computation capabilities conceived to explore novel and unconventional RFID applications. RAMSES implements an RF energy-harvesting circuit enhanced by a dc-dc voltage booster in silicon-on-insulator technology, an ultralow-power microcontroller, temperature, light, and acceleration sensors, and a new-generation I^2C -RFID chip to wirelessly deliver sensor data to standard RFID EPCglobal Class-1 Generation-2 readers. A preliminary RAMSES prototype, fabricated on a printed circuit board using low-cost off-the-shelf discrete components, has been extensively tested through experiments conducted both in lab and real-world application scenarios. The achieved results have demonstrated the ability of RAMSES to harvest the RF energy emitted by an interrogator placed up to 10 m of distance and autonomously perform sensing, computation, and data communication. To our knowledge, this is the longest range ever reported for fully passive RFID sensors. Furthermore, for applications requiring larger operating distances, RAMSES provides also a battery-assisted passive mode yielding up to 22-m communication range. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
33. A Power Management System for Multianode Benthic Microbial Fuel Cells.
- Author
-
Umaz, Ridvan, Garrett, Caleb, Qian, Fengyu, Li, Baikun, and Wang, Lei
- Subjects
MICROBIAL fuel cells ,ANODES ,ELECTRONIC equipment ,PROTOTYPES ,ELECTRONS - Abstract
Benthic microbial fuel cells (BMFCs) are important energy-harvesting devices for underwater sensors and electronic devices. However, it is a challenging problem to ensure the robustness of BMFCs in harsh ocean environment. In particular, the anode buried in sediment is subject to burrowing organisms tunneling, which breaks the anaerobic condition, and the electrons generated by the anode will be consumed locally. This eliminates the difference in electric potential between the anode and the cathode. The system then becomes short-circuited and ceases to function. This is a serious problem in the underwater environment due to the likelihood of bioturbation. Using a multianode BMFC can effectively address this problem due to the distributed structure of multiple anodes. This, however, requires a new power management system (PMS) to automatically detect and remove the effect of impaired anodes. This paper presents a new PMS for multianode BMFCs. The proposed PMS automatically disconnects the impaired anodes from the rest of the system for bioturbation resilience and better efficiency. The proposed PMS is self-starting, i.e., no need of extra power sources other than the BMFC. The PMS has been tested through a prototype BFMC. Experimental results demonstrate the effectiveness of this design for multianode BMFCs. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. Versatile Stimulation Back-End With Programmable Exponential Current Pulse Shapes for a Retinal Visual Prosthesis.
- Author
-
Maghami, Mohammad Hossein, Sodagar, Amir M., and Sawan, Mohamad
- Subjects
PROSTHESIS design & construction ,ON-chip charge pumps ,CURRENT conveyors - Abstract
This paper reports on the design, implementation, and test of a stimulation back-end, for an implantable retinal prosthesis. In addition to traditional rectangular pulse shapes, the circuit features biphasic stimulation pulses with both rising and falling exponential shapes, whose time constants are digitally programmable. A class-B second generation current conveyor is used as a wide-swing, high-output-resistance stimulation current driver, delivering stimulation current pulses of up to \pm 96~\muA to the target tissue. Duration of the generated current pulses is programmable within the range of 100~\mus to 3 ms. Current-mode digital-to-analog converters (DACs) are used to program the amplitudes of the stimulation pulses. Fabricated using the IBM 130 nm process, the circuit consumes 1.5\times 1.5~mm^2 of silicon area. According to the measurements, the DACs exhibit DNL and INL of 0.23 LSB and 0.364 LSB, respectively. Experimental results indicate that the stimuli generator meets expected requirements when connected to electrode-tissue impedance of as high as 25 k\Omega. Maximum power consumption of the proposed design is 3.4 mW when delivering biphasic rectangular pulses to the target load. A charge pump block is in charge of the upconversion of the standard 1.2-V supply voltage to \pm 3.3V. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
35. A −8 mV/+15 mV Double Polarity Piezoelectric Transformer-Based Step-Up Oscillator for Energy Harvesting Applications.
- Author
-
Camarda, Antonio, Tartagni, Marco, and Romani, Aldo
- Subjects
PIEZOELECTRIC devices ,ELECTRIC transformers ,ENERGY harvesting - Abstract
This paper presents two circuit topologies of battery-less integrated boost oscillators suitable for kick-starting electronic systems in fully discharged states with ultra-low input voltages, in the context of energy harvesting applications based on thermoelectric generators, by coupling a piezoelectric transformer in a feedback loop. With respect to the prior work, the first presented solution is a double polarity circuit designed in a 0.18~\mu \textm CMOS technology able to boost ultra-low positive and negative voltages without using switching matrixes. The circuit exploits a CMOS inverter made up of low threshold transistors, and also includes a hysteretic voltage monitor consuming only ~15 nW to enable an external circuit. The minimum achieved positive and negative oscillation voltages are +15 and −8 mV, which to the best of the authors’ knowledge, are among the lowest start-up voltages achieved in literature up to now without using magnetic components. Moreover, the input impedance in the range of several \textk\Omega makes the presented solution suitable also for high impedances sources, such as rectennas. The second presented circuit, designed in a 0.32~\mu \textm CMOS technology, exploits an input stage based on depletion-mode MOSFETs in a common source stage configuration and achieves a maximum step ratio of ~60. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
36. Self-Annealing Effect of Tensile Liner on Thick-Tinv PMOS.
- Author
-
Zhang, Qintao, Chen, Jie, and Sherony, Melanie J.
- Subjects
ANNEALING of semiconductors ,METAL oxide semiconductors ,TRANSISTORS ,INTEGRATED circuit passivation ,ON-chip charge pumps ,INTERFACE circuits ,PERFORMANCE evaluation - Abstract
Various techniques have been applied in modern CMOS technology to passivate interface traps, thus improving digital performance and reliability. Although these methods are effective, they all clearly add process complexity and cost. In this paper, a novel method, without adding a single extra step, is introduced to reduce thick-Tinv PMOS interface trap density. Experimental results confirm that depositing a tensile liner film first in the dual stress liner process can reduce the interface trap density of thick-Tinv PMOS effectively. The passivation, which is verified by charge pumping results, is believed to be due to the annealing effect of the hydrogen in the tensile liner driven by the UV anneal step used in stress transfer. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
37. A –21.2-dBm Dual-Channel UHF Passive CMOS RFID Tag Design.
- Author
-
Yao, Chia-Yu and Hsia, Wei-Chun
- Subjects
CMOS integrated circuits ,MICROSTRIP antennas ,RADIO frequency identification systems ,BACKSCATTERING ,ENERGY harvesting ,RADIO frequency - Abstract
Previous research results showed that UHF passive CMOS RFID tags had difficulty to achieve sensitivity less than -20~dBm. This paper presents a dual-channel 15-bit UHF passive CMOS RFID tag prototype that can work at sensitivity lower than -20~dBm. The proposed tag chip harvests energy and backscatters uplink data at 866.4-MHz (for ETSI) or 925-MHz (for FCC) channel and receives downlink data at 433-MHz channel. Consequently, the downlink data transmission does not interrupt our tag from harvesting RF energy. To use the harvested energy efficiently, we design a tag chip that includes neither a regulator nor a VCO such that the harvested energy is completely used in receiving, processing, and backscattering data. Without a regulator, our tag uses as few active analog circuits as possible in the receiver front-end. Instead, our tag uses a novel digital circuit to decode the received data. Without a VCO, the design of our tag can extract the required clock signal from the downlink data. Measurement result shows that the sensitivity of the proposed passive tag chip can reach down to -21.2~dBm. Such result corresponds to a 19.6-m reader-to-tag distance under 36-dBm EIRP and 0.4-dBi tag antenna gain. The chip was fabricated in TSMC 0.18-\mum CMOS process. The die area is 0.958 mm \times 0.931mm. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
38. Steep-Gain Bidirectional Converter With a Regenerative Snubber.
- Author
-
Yao, Jia, Abramovitz, Alexander, and Ma Smedley, Keyue
- Subjects
SNUBBERS (Electrical engineering) ,DC-to-DC converters ,ON-chip charge pumps ,ELECTRIC inductors ,TOPOLOGY - Abstract
This paper introduces a SEPIC-derived bidirectional dc–dc converter. The proposed converter utilizes tapped inductor and charge pump techniques to achieve steep voltage conversion ratio and an active lossless regenerative snubber to attain lossless switching and high efficiency. The paper presents the principle of operation, steady-state analyses, and experimental results obtained from a 400-W, 48-V/380-V prototype. The efficiency of the proposed topology is demonstrated to peak at 96.4% for boost mode and 95.0% for buck mode. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
39. Low-Input Power-Level CMOS RF Energy-Harvesting Front End.
- Author
-
Abouzied, Mohamed A. and Sanchez-Sinencio, Edgar
- Subjects
COMPLEMENTARY metal oxide semiconductors ,ENERGY harvesting ,RENEWABLE energy sources ,ENERGY conversion ,RADIO frequency - Abstract
RF energy-harvesting front ends consist of LC matching networks and RF rectifiers. The minimum detectable power (sensitivity) is dependent on the losses of both parts. In this paper, RF energy-harvesting sensitivity limits at steady state and design tradeoffs for matching networks and rectifiers are introduced. These limits and tradeoffs are examined for standard CMOS 0.18-\mum technology. Two designs, one with off-chip matching network and the other with on-chip matching network, are presented, compared, and measured for an output voltage of 1 V. The sensitivity of the off-chip design is -\27.3 dBm while taking 180\,\times\,90 \mum^2 die area and off-chip high quality inductor and capacitor, which takes an extra 7.28 mm^2 printed circuit board area. The fully integrated on-chip design has a sensitivity of -\21.7 dBm while taking 820\,\times\,450 \mum^2 die area. The sensitivity of the former proved superior while the latter is more attractive in terms of compactness, low cost, and easier tunability. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
40. Analysis and Design of Charge Pump-Assisted High Step-Up Tapped Inductor SEPIC Converter With an “Inductorless” Regenerative Snubber.
- Author
-
Yao, Jia, Abramovitz, Alexander, and Smedley, Keyue Ma
- Subjects
ON-chip charge pumps ,CASCADE converters ,RENEWABLE energy sources ,ELECTRIC inductors ,COMPUTER simulation ,SOLAR cells - Abstract
This paper introduces a SEPIC-derived converter suited for alternative energy generation applications. The proposed converter utilizes tapped inductor and charge pump techniques to achieve high step-up gain and a passive regenerative snubber to attain high efficiency. Compared with earlier counterparts, the proposed converter has the advantage of continuous input current, which can be helpful in attaining accurate tracking of maximum power point of solar panels. The paper presents principle of operation, theoretical analysis, and design guidelines. Theoretical expectations were confirmed by simulation and experimental results. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
41. A Low-Power Delta-Sigma Modulator Using a Charge-Pump Integrator.
- Author
-
Nilchi, Alireza and Johns, David A.
- Subjects
INTEGRATORS ,ON-chip charge pumps ,DELTA-sigma modulation ,THERMAL noise ,INTEGRATED circuits - Abstract
In this paper a low-power switched-capacitor integrator based on a capacitive charge-pump (CP) is presented, and its practical effects are discussed. The CP integrator is employed as the first stage of a \Delta\Sigma ADC. The 0.13 \mum CMOS prototype of the CP based ADC achieves the same performance as a conventional ADC while consuming 66% lower OTA power in the front-end integrator. The CP based modulator realizes 87.8 dB SNDR, 89.2 dB SNR and 90 dB DR over a 10 kHz bandwidth with 148 \muW power consumption. The conventional ADC has similar performance but dissipates 241 \muW. The energy required per conversion-step for the CP based ADC (0.369 pJ/step) is almost 40% lower than that of the conventional ADC (0.607 pJ/step). [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
42. A 1.62 Gb/s–2.7 Gb/s Referenceless Transceiver for DisplayPort v1.1a With Weighted Phase and Frequency Detection.
- Author
-
Song, Junyoung, Jung, Inhwa, Song, Minyoung, Kwak, Young-Ho, Hwang, Sewook, and Kim, Chulwoo
- Subjects
RADIO transmitter-receivers ,RADIO frequency ,FREQUENCY discriminators ,ENERGY consumption ,COMPLEMENTARY metal oxide semiconductors ,VOLTAGE-controlled oscillators - Abstract
This paper proposes a 2.7 Gb/s referenceless transceiver with weighted PFD for frequency detection of random signals. A single loop referenceless CDR is also proposed to overcome the disadvantages of a dual loop CDR. The ANSI 8b/10b encoder & decoder with the scrambler, the serializer & de-serializer, and the output driver with pre-emphasis are included in the proposed transceiver architecture for DisplayPort v1.1a. The jitter of the generated clock at the Tx PLL is 3.28 psrms at 2.7 Gb/s with 1.2 V supply. The eye opening of the transmitter output with 3 m cable is 0.54 UI. The measured jitter of the recovered clock at the CDR is 1.57 psrms, and BER is less than 10^-12. The receiver consumes 23 mW at 2.7 Gb/s with 1.2 V supply. The CDR core and transceiver occupy 0.07 mm^2 and 0.94 mm^2, respectively, in a 0.13 \mum 1P8M CMOS process. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
43. A Dual-Loop Clock and Data Recovery Circuit With Compact Quarter-Rate CMOS Linear Phase Detector.
- Author
-
Yung Sern Tan, Kiat Seng Yeo, Chirn Chye Boon, and Manh Anh Do
- Subjects
COMPLEMENTARY metal oxide semiconductors ,CONSTANT fraction discriminator ,PHASE detectors ,ELECTRONIC equipment ,DATA analysis - Abstract
This paper presents a 5-Gb/s dual-loop clock and data recovery (CDR) circuit with a compact quarter-rate linear phase detector (PD). The proposed PD not only reduces the complexity of the circuit structure but also employs an UP pulse-widening technique to circumvent the problem of existing narrow UP pulses. Meanwhile, it has the least number of output signals among all the other linear PDs with UP pulse-widening technique. It also provides a data recovery circuit to de-multiplex the input data with no systematic phase offset. An unbalanced charge pump (CP) is also proposed to compensate the unbalanced pulse-width of UP and DN pulses as well as the unequal number of signal between UP and DN pulses. A detailed propagation delay analysis and a set of equations to predict the characteristic curve of the proposed PD is given. In addition, a lock detector with hysteresis property is implemented to ensure proper switching of the loops. Fabricated in 0.18- μm CMOS technology, the circuit shows that the peak-to-peak jitter of the recovered clock is 30.4-ps and it consumes 71.9-mW from a 1.8 V supply. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
44. Analysis and Design Techniques for Supply-Noise Mitigation in Phase-Locked Loops.
- Author
-
Arakali, Abhijith, Gondi, Srikanth, and Hanumolu, Pavan Kumar
- Subjects
PHASE-locked loops ,DEMODULATION ,NOISE measurement ,VOLTAGE regulators ,COMPLEMENTARY metal oxide semiconductors - Abstract
Supply noise affects the jitter performance of ring oscillator-based phase-locked loops (PLLs) significantly. While the focus of much of the prior art is on supply noise in oscillators, this paper illustrates that supply noise in other building blocks also contribute significantly to PLL output jitter. Analytical expressions for supply-noise sensitivities are derived for each of the circuit blocks used in the PLL and insight into the mechanism through which supply noise appears at the PLL output is provided. Efficient supply-regulation schemes that combine a split-tuned PLL architecture with an optimized low-dropout regulator to achieve better than -22~dB of worst case supply-noise sensitivity for the whole PLL are presented. Fabricated in a 0.18~\mum digital CMOS process, the prototype PLL occupies an area of 0.18~\mum and operates from a 1.8 V supply. At 1.5 GHz, the total power consumption is 3.3 mW, of which 0.54 mW is consumed in the regulators. The measured output peak-to-peak jitter is 33 ps and 41 ps with no supply noise and with a 100-mV amplitude supply noise tone injected at the worst case noise frequency, respectively. [ABSTRACT FROM PUBLISHER]
- Published
- 2010
- Full Text
- View/download PDF
45. A Boost-Type Nine-Level Switched Capacitor Inverter.
- Author
-
Nakagawa, Yuya and Koizumi, Hirotaka
- Subjects
CAPACITOR switching ,PULSE width modulation transformers ,ELECTRIC capacity ,ON-chip charge pumps ,CAPACITORS ,VOLTAGE control ,MULTI-carrier modulation - Abstract
A new boost-type multilevel inverter using switched capacitor structure is proposed. The main feature of the proposed inverter is boosting and multilevel output with small number of components. Due to the passive voltage balancing of each capacitor maintains a constant voltage without additional control. In this paper, the operation principle, the modulation method, the voltage/current stresses on switches and the determination of capacitances, the simulation results with MATLAB/Simulink R2015a, the experimental results, and the 2-kW simulation are shown. The simulation and the experiments were conducted under resistive load and inductive load conditions. In addition, the load variation was conducted in the experiment. Under both resistive load and inductive load conditions, the obtained waveforms by simulation and experiment agreed well with the theory. In the load variation experiment, the obtained waveforms were not distorted and the capacitor voltages maintained constant. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Fully Integrated Low-Power Energy Harvesting System With Simplified Ripple Correlation Control for System-on-a-Chip Applications.
- Author
-
Shim, Minseob, Jeong, Junwon, Maeng, Junyoung, Park, Inho, and Kim, Chulwoo
- Subjects
ENERGY harvesting ,SYSTEMS on a chip ,ON-chip charge pumps ,RELIABILITY in engineering ,CAPACITORS - Abstract
This paper presents a fully integrated energy harvesting (EH) system that even includes an input capacitor and a simplified ripple correlation control (RCC) maximum power point tracking (MPPT) method for low-power system-on-a-chip applications. The proposed system implements the RCC block with a charge pump (CP) that can be integrated into the chip, instead of the inductive switching converter that is commonly used for conventional RCC methods. The CP changes the input impedance by changing the size of the flying capacitor to ensure system reliability. The simplified RCC method is implemented using a low-power analog divider operated in a subthreshold region. A test chip fabricated in a 180 nm CMOS process achieves over 95% MPPT accuracy with a very small input capacitor of 5 nF and a low quiescent current of 2.6 μA. The chip size of the entire system is 8 mm2, and the harvested power range is from 6 μW to 1.4 mW. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
47. Optimization of Sine-Wave Clocking for High-Frequency AC–DC Conversion.
- Author
-
Hsu, Stephanie and Poon, Ada S. Y.
- Subjects
ELECTRIC power conversion ,ALTERNATING currents ,DIRECT currents ,WIRELESS power transmission ,ENERGY harvesting - Abstract
Wireless energy harvesting devices convert received ac energy into dc voltages suitable to power the back-end functionality of the devices. The low energy available to the devices require high ac–dc conversion efficiency in order for enough power to be delivered to the load. This paper presents a model to characterize loss through charge pump cells in wireless energy harvesting devices. The proposed model includes the time-domain effects of the input radio-frequency energy wave and provides additional insight into how clock and switch parameters along with architecture considerations can be used to improve the efficiency of ac–dc conversion. Results are verified using simulation in a 0.18- $\mu$ m CMOS technology. We show the impact of threshold voltage on reverse conduction and the limitations on increasing transistor switch sizes to support high current loads. Design examples use the presented model to optimize design parameters to decrease loss in the charge pump. We compare the performance between sine-wave and square-wave clocked charge pumps to show the tradeoff between charge pump loss and clock generation power consumption. Furthermore, the benefits of easily computing architectural changes is demonstrated using the proposed model showing how the calculated equivalent resistance can be used to determine the benefits of mixed-mode clocking. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
48. Post-Layout Simulation Time Reduction for Phase-Locked Loop Frequency Synthesizer Using System Identification Techniques.
- Author
-
Liu, Lechang and Pokharel, Ramesh
- Subjects
PHASE-locked loops ,ELECTRIC oscillators ,NEURAL circuitry ,DEMODULATION ,SYSTEM identification ,SYSTEM analysis ,COMPLEMENTARY metal oxide semiconductors - Abstract
Compact model extraction of phase-locked loop (PLL) frequency synthesizer using system identification techniques is proposed to reduce post-layout simulation time. This is the first published compact model for PLL using system identification techniques. It features an autoregressive exogenous model for the charge pump and the loop filter with a lookup table for nonlinearity compensation and a radial basis function neural network for the voltage-controlled oscillator with nonlinear frequency-voltage relationship, thereby reducing the post-layout simulation time to 26% of the original circuits with the accuracy of 93%. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
49. Delta Modulation Technique for Improving the Sensitivity of Monobit Subsamplers in Radar and Coherent Receiver Applications.
- Author
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Rodenbeck, Christopher T., Tracey, Keith J., Barkley, Keith R., and DuVerneay, Brian B.
- Subjects
DELTA modulation ,RADAR ,RADIO frequency ,ANALOG-to-digital converters ,WAVE analysis ,SIGNAL-to-noise ratio - Abstract
This paper introduces a technique for improving the sensitivity of RF subsamplers in radar and coherent receiver applications. The technique, referred to herein as “delta modulation” (DM), feeds the time-average output of a monobit analog-to-digital converter (ADC) back to the ADC input, but with opposite polarity. Assuming pseudostationary modulation statistics on the sampled RF waveform, the feedback signal corrects for aggregate dc offsets present in the ADC that otherwise degrade ADC sensitivity. Two RF integrated circuits (RFICs) are designed to demonstrate the approach. One uses analog DM to create the feedback signal; the other uses digital DM to achieve the same result. A series of tests validates the designs. The dynamic time-domain response confirms the feedback loop's basic operation. Measured output quantization imbalance, under noise-only input drive, significantly improves with the use of the DM circuit, even for large, deliberately induced dc offsets and wide temperature variation from -55 ^\circC to +\85 ^\circC. Examination of the corrected versus uncorrected baseband spectrum under swept input signal-to-noise ratio (SNR) conditions demonstrates the effectiveness of this approach for realistic radar and coherent receiver applications. Two-tone testing shows no impact of the DM technique on ADC linearity. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
50. Synthesis and Comparative Analysis of Very High Step-Up DC?DC Converters Adopting Coupled-Inductor and Voltage Multiplier Cells.
- Author
-
Andrade, Antonio Manuel Santos Spencer, Mattos, Everson, Schuch, Luciano, Hey, Helio Leaes, and da Silva Martins, Mario Lucio
- Subjects
DIRECT currents ,CONVERTERS (Electronics) ,VOLTAGE multipliers ,ELECTRIC inductors ,COMPARATIVE studies - Abstract
A synthesis methodology for developing a set of very high step-up dc–dc converters is presented and discussed in this paper. The proposed method makes use of a boost converter as basic topology in which three step-up techniques are combined and incorporated. The studied techniques are the switched capacitors voltage multipliers (VM), the diode VMs, and the coupled-inductors. With the proposed methodology, many well-known converters are identified and two novel converters are proposed. In addition to a detailed analysis of the synthesis of each topology, a comparative analysis among of some important converters is presented. This comparison involves aspects such as voltage gain, voltage stress, component stress factor, component count, and relative cost. By means of these comparisons, the main characteristics and constraints of the analyzed converters are identified. Results from 250 W prototypes, designed according to photovoltaic ac-module specifications, are obtained experimentally to validate the theoretical analyses and point out advantages and limitations of each converter. The results demonstrate that the combination of the three studied techniques provides the best trend off on the comparative analysis carried out in this work. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
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