Wireless Power Receiver Research Articles

An Adaptive On-Off-Delay Compensation Scheme Based on Dead-Time and Rectified-Current Sampling for Ampere-Current-Level Series-Series Wireless Power Receivers

An Adaptive On-Off-Delay Compensation Scheme Based on Dead-Time and Rectified-Current Sampling for Ampere-Current-Level Series-Series Wireless Power Receivers

A Wirelessly Powered Scattered Neural Recording Wearable System.

This paper introduces a wirelessly powered scattered neural recording wearable system that can facilitate continuous, untethered, and long-term electroencephalogram (EEG) recording. The proposed system, including 32 standalone EEG recording devices and a central controller, is incorporated in a wearable form factor. The standalone devices are sparsely distributed on the scalp, allowing for flexible placement and varying quantities to provide extensive spatial coverage and scalability. Each standalone device featuring a low-power EEG recording application-specific integrated circuit (ASIC) wirelessly receives power through a 60 MHz inductive link. The low-power ASIC design (84.6 μW) ensures sufficient wireless power reception through a small receiver (Rx) coil. The 60 MHz inductive link also serves as the data carrier for wireless communication between standalone devices and the central controller, eliminating the need for additional data antennas. All these efforts contribute to the miniaturization of standalone devices with dimensions of 12×12×5 mm3, enhancing device wearability. The central controller applies the pulse width modulation (PWM) scheme on the 60 MHz carrier, transmitting user commands at 4 Mbps to EEG recording ASICs. The ASIC employs a novel synchronized PWM demodulator to extract user commands, operating signal digitization and data transmission. The analog frontend (AFE) amplifies the EEG signal with a gain of 45 dB and applies band-pass filtering from 0.03 Hz to 400 Hz, with an input-referred noise (IRN) of 3.62 μVRMS. The amplified EEG signal is then digitized by a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) with a peak signal-to-noise and distortion ratio (SNDR) of 55.4 dB. The resulting EEG data is transmitted to an external software-defined radio (SDR) Rx through load-shift-keying (LSK) backscatter at 3.75 Mbps. The system's functionality is fully evaluated in human experiments.

A 9-V Wireless Power Receiver IC With 74.2% Power Conversion Efficiency and Integrated Bidirectional Telemetries for Implantable Neurostimulation Systems in Standard CMOS

A 9-V Wireless Power Receiver IC With 74.2% Power Conversion Efficiency and Integrated Bidirectional Telemetries for Implantable Neurostimulation Systems in Standard CMOS

A Power-Efficient Envelope-Detector-Less Amplitude-Shift-Keying Forward Telemetry for Wirelessly Powered Biomedical Devices.

This paper proposes an envelope-detector-less (EDL) amplitude-shift-keying (ASK) forward telemetry (FT) demodulator for wireless power/data transfer (WPDT) systems. The EDL ASK FT demodulator can substitute bulky and power-hungry components, which are an envelope detector and an analog comparator in the conventional ASK FT demodulator, with a digital controller, reducing both power dissipation and chip area. The proposed demodulator shares the gate control signals of pass transistors, which are used in an ac-dc regulator for wireless power reception, to maintain a constant load voltage while efficiently demodulating the forward telemetry data. Also, a proposed digital cleaner in the EDL demodulator refines this control signal into a wide pulse without suffering from resonant frequency noise, while a synchronizer can align its frequency with the data rate and resonant frequency. The 0.25-μm CMOS prototype chip of the proposed power-path-less EDL ASK FT demodulator, equipped with the ac-dc regulator, demonstrates a significant 38.2% reduction in power dissipation compared to the conventional ASK FT demodulator. Moreover, the EDL ASK FT demodulator occupies only 0.023-mm2 silicon area and achieves a low bit error rate (BER) less than 10-4 while maintaining a regulated voltage of 4.5 V on the load.

The Impact of Rectifier Filter Capacitance on Buck Converter Output Voltage in Wireless Power Receiver System With Input Current Source

The Impact of Rectifier Filter Capacitance on Buck Converter Output Voltage in Wireless Power Receiver System With Input Current Source

MagSonic: Hybrid Magnetic-Ultrasonic Wireless Interrogation of Millimeter-Scale Biomedical Implants With Magnetoelectric Transducer.

Wireless interrogation (power and data transfer) of biomedical implants, miniaturized to millimeter (mm) dimensions, is critical for their chronic operation. Achieving simultaneous wireless power and data transfer at deep sites reliably within safety limits for closed-loop sensing/actuation functions of mm-sized implants is challenging. To enable this operation, a hybrid magnetic-ultrasonic interrogation approach (called MagSonic) is realized through a single magnetoelectric (ME) transducer at the implant that can generate and receive both magnetic field and ultrasound. The fabricated mm-sized bar-shaped ME transducer (5.2×2×1.6 mm3) operates at acoustic wave resonance, functioning at sub-MHz frequencies. For the first time, we demonstrate wireless power reception through one modality (magnetic field or ultrasound) and simultaneous uplink data transmission using the other. At 40 mm depth, the MagSonic link could achieve 100 kbps uplink data rate (bit error rate ≤ 10-5) using 190 pJ/bit transmitted energy and 8 mW delivered power in tissue. The robustness of the MagSonic interrogation link against power carrier interference and misalignments is also demonstrated.

A battery-free anti-inflammatory brain remote for spatiotemporal guiding movement of mice

The brain-machine-interface (BMI) system designed for the regulation of neural activity represents a cutting-edge technology in contemporary society, holding promising potential for applications in sensory substitution, neural disease treatment, and behavioral intervention. In this study, a novel battery-free anti-inflammatory brain remote has been innovated to guide the movement of mice. Characterized by a biologically inspired design, the device is capable of wireless power reception and control through a mobile phone utilizing the piezoelectric effect triggered by audio playback. Comprising two essential components—namely, the pedestal and the crest—the former is semi-invasively implanted on the head, featuring strategically positioned electrodes within specific brain regions. Additionally, the pedestal incorporates a drug-delivery microneedle array with antibacterial properties (PEG-ZnO nanorods), effectively mitigating the risk of postoperative infection and ensuring long-term wearability. The crest is constructed with an acoustic resonant cavity and a piezoelectric transducer, facilitating the reception of programmed acoustic waves and the subsequent output of neural electrostimulation signals. In vivo experiments involving the stimulation of the primary somatosensory barrel cortex (S1BF) in freely moving mice demonstrated the device's real-time influence on their body-turning behaviors. These findings underscore a wireless, self-powered, and biologically friendly approach, contributing to the advancement of remote brain-machine interfaces.

Capacitive-Coupling-Responsive Hydrogel Scaffolds Offering Wireless In Situ Electrical Stimulation Promotes Nerve Regeneration.

Electrical stimulation (ES) has shown beneficial effects in repairing injured tissues. However, current ES techniques that use tissue-traversing leads and bulky external power suppliers have significant limitations in translational medicine. Hence, exploring noninvasive in vivo ES to provide controllable electrical cues in tissue engineering is an imminent necessity. Herein, a conductive hydrogel with in situ electrical generation capability as a biodegradable regeneration scaffold and wireless ES platform for spinal cord injury (SCI) repair is demonstrated. When a soft insulated metal plate is placed on top of the injury site as a wireless power transmitter, the conductive hydrogel implanted at the injury site can serve as a wireless power receiver, and the capacitive coupling between the receiver and transmitter can generate an alternating current in the hydrogel scaffold owing to electrostatic induction effect. In a complete transection model of SCI rats, the implanted conductive hydrogels with capacitive-coupling in situ ES enhance functional recovery and neural tissue repair by promoting remyelination, accelerating axon regeneration, and facilitating endogenous neural stem cell differentiation. This facile wireless-powered electroactive-hydrogel strategy thus offers on-demand in vivo ES with an adjustable timeline, duration, and strength and holds great promise in translational medicine.

An Energy-Efficient Wireless Power Receiver With One-Step Adiabatic-Bipolar-Supply Generating for Implantable Electrical Stimulation Applications.

This paper presents an energy-efficient wireless power receiver for implantable electrical stimulation applications, which can achieve one-step adiabatic bipolar-supply that is generated by a hybrid single-stage dual-output regulating (SSDOR) rectifiers. The structure using only four switches overcomes the disadvantages that the two output voltage values in the traditional dual-output rectifiers are close to each other. A constant-current (CC) controlled adiabatic dynamic voltage scaling (DVS) technique is proposed to minimize the voltage headroom of the stimulating drivers and improve the stimulation efficiency significantly. In addition, the receiver adopts only one general constant on-time (COT) low-frequency control to adjust the stimulation current, reducing both the power consumption and the complexity of the control circuits. The proposed receiver has been fabricated in a 0.18 μm BCD process with ±6 V voltage compliance and 2.5 mA maximum stimulating current. With a current range from ±1.5 mA to ±2.5 mA, the measured maximum average headroom voltage is only 80 mV and the peak total efficiency of the receiver is 85.6 %. The functionalities of the proposed receiver have been successfully verified through in vitro experiments.

All Rivers Flow to the Sea: A High-Density Wireless Power Receiver With Split-Dual-Path and Hybrid-Quad-Path Step-Down Rectifying Conversion

All Rivers Flow to the Sea: A High-Density Wireless Power Receiver With Split-Dual-Path and Hybrid-Quad-Path Step-Down Rectifying Conversion

Reducing the Input Capacitance to Minimize the Right-Half-Plane Zero Effect for Buck Converters in Wireless Power Receiver Systems

Reducing the Input Capacitance to Minimize the Right-Half-Plane Zero Effect for Buck Converters in Wireless Power Receiver Systems

Solar Wireless Charging For Electric Vehicle While Driving

This paper presents a novel concept of solar wireless charging for electric vehicles (EVs) while driving. The idea is to integrate solar panels into the roads and use wireless charging technology to transfer energy from the solar panels to the EVs. . To overcome these challenges, several approaches have been proposed, including increasing battery capacity, improving charging infrastructure, and using alternative energy sources. One promising approach is to use solar energy to charge EVs while driving. Solar energy is abundant and renewable, and it can be harnessed using solar panels installed on the roads. However, traditional charging methods, such as plug-in charging, have limitations in terms of convenience and efficiency. Wireless charging technology, on the other hand, has the potential to overcome these limitations by enabling charging while driving without the need for physical connections. we propose a novel concept of solar wireless charging for EVs while driving. The proposed system integrates solar panels into the roads and uses wireless charging technology to transfer energy from the solar panels to the Evs. Key words: Electric road system, wireless power transfer, transmitter and receiver coils, power lanes, e-vechile ,charging while driving, no battery drain, easy to use, get charge while running , future oriented.

Harmonic-Based Integrated Rectifier–Transmitter for Uncompromised Harvesting and Low-Power Uplink

Wireless uplink of a sensor node based on modulating rectifier-generated harmonics is promising for lowered energy consumption and Tx-to-Rx leakage. The existing solutions need to balance between maintaining the rectification performance and modulating the reradiated harmonic. In this article, a novel controllable second-harmonic termination (CSHT) is proposed to modulate the reradiated second harmonic in amplitude without compromising the wireless power reception. By combining a CSHT and a rectifier, an integrated rectifier–transmitter (IRT) is formed. An analytical model is derived for designing CSHTs, while the relationship between the CSHT, the diode impedance, and the reradiated harmonic power is revealed for the IRT. As a proof of concept, an IRT prototype at 2.4GHz was designed and experimented. An uplink data rate of 2 Mb/s was achieved when the IRT was fed by a transmitter with +25-dBm output power at a distance of 4 m. The data transmission of the proposed IRT consumes power less than 12.2 pJ/bit while maintaining the wireless power rectification performance.

A Design of Wireless Power Receiver With Gate Charge Recycled Dual-Mode Active Rectifier and Step-Down Converter With 88.2% System Efficiency for Power Management IC

This article presents a power management integrated circuit for a wireless power receiver unit. A dual-mode high-efficiency active rectifier design is based on alliance for wireless power (A4WP) and wireless power consortium (WPC) standards. A gate charge recycling technique is proposed in the dual-mode active rectifier so that the current generated by the switching of the high side gate driver can be recycled to the rectifier output voltage in order to enhance efficiency. A step-down dc–dc converter with a proposed bootstrap circuit and dynamic pull-up resistor gate driver circuit is designed. The chip is implemented in a 0.18-μm bipolar-CMOS double-diffused metal-oxide-semiconductor process. The total die area, including the pad, is 2.64 mm × 2.6 mm. The measurement results show that the active rectifier achieves peak power conversion efficiency (PCE) of 94.7% and generates an output voltage of 7.68 V in WPC mode and 9.1 V with 93.4% efficiency in A4WPC mode. The input voltage varies from 10 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-P</sub> –12 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-P</sub> . Similarly, the step-down dc–dc converter obtains a peak PCE of 93.2% at a load current of 500 mA while producing an output voltage of 5 V. The overall system efficiency at A4WP and WPC mode are 86.7% and 88.2%, respectively.

An Auto-Reconfigurable Multi-Output Regulating Switched-Capacitor DC–DC Converter for Wireless Power Reception and Distribution in Multi-Unit Implantable Devices

An automatically reconfigurable switched-capacitor DC-DC converter with multiple regulated outputs is presented for wireless-powered multi-unit implantable medical devices (IMDs). In such devices, the main controller unit is powered wirelessly and provides supply voltages to the circuits of the main unit as well as multiple connected sub-units. The proposed DC-DC converter simultaneously generates two regulated voltages for the main unit and two unregulated voltages for the sub-units, which have on-site low-dropout regulators. The converter consists of i) an input-adaptive DC-DC conversion stage with two switched-capacitor (SC) DC-DC converters in series and ii) a regulating stage. In the DC-DC conversion stage, the proposed converter automatically reconfigures the conversion ratio and connection order of the two SC DC-DC converters and selects the output nodes by load selection switches depending on the input level. Thanks to these adaptive configurations, the proposed converter offers high conversion efficiencies over a wide input voltage range even with fewer flying capacitors required for the reconfigurable conversion ratios. Moreover, the selection switches are reused to regulate the output voltages to desired levels, minimizing the overhead for subsequent regulation. The IC fabricated in a 180-nm standard CMOS process achieves a conversion efficiency of 95.5% for the unregulated voltages and up to 77.4% for the regulated voltages over a wide input range of 1 V to 4 V with 0.74-mV output ripple for a load current of 20 mA, while providing four outputs (2 regulated, 2 unregulated).

Modeling and Characterization of Pre-Charged Collapse-Mode CMUTs

Recently, the applications of ultrasound transducers expanded from high-end diagnostic tools to point of care diagnostic devices and wireless power receivers for implantable devices. These new applications additionally require that the transducer technology must comply to biocompatibility and manufacturing scalability. In this respect, Capacitive Micromachined Ultrasound Transducers (CMUTs) have a strong advantage compared to the conventional PZT based transducers. However, current CMUTs require a large DC bias voltage for their operation, which limits the miniaturizability of these devices. In this study, we propose a pre-charged collapse-mode CMUT for immersive applications that can operate without an external bias by means of a charge trapping Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> layer embedded in the dielectrics between the top and bottom electrodes. The built-in charge layer was analytically modeled and four layer stack combinations were investigated and characterized. The measurement results of the CMUTs were then used to fit the model and to quantify the amount and type of trapped charge. It was found that these devices polarize due to the ferroelectric-like behavior of the Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , and the amount of charge stored in the charge-trapping layer was estimated to be approximately 0.02C/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Their acoustic performance shows a transmit and receive sensitivity of 8.8 kPa/V and 13.1V/MPa respectively. In addition, we show that increasing the charging temperature, the charging duration, and the charging voltage results in a higher amount of stored charge. Finally, results of ALT tests showed that these devices have a lifetime of more than 2.5 years at body temperature.

Novel Measurement Method to Determine Optimum Reception Frequency of Electric Field Wireless Power Receiver

Novel Measurement Method to Determine Optimum Reception Frequency of Electric Field Wireless Power Receiver

Frequency offset suppression method for wireless power transfer based on nonlinear resonant network

SummaryIn magnetically resonant wireless power transfer (MR‐WPT) systems, transmitter, and receiver usually operate at the same resonant frequency. However, parameters of inductor, capacitor, or other components are susceptible to changes due to environmental factors and cause resonant frequency deviation. This would lead to decrease of transmission performance. To solve the problem, a wireless power transfer system based on a nonlinear compensation network is proposed to suppress frequency offset. The modeling of the nonlinear MR‐WPT system is first established. On this basis, the mathematical equation of the equivalent nonlinear circuit is deduced and the amplitude‐frequency response characteristics are analyzed. The influence of inductance parameter on the nonlinear characteristic is studied. Furthermore, the effects of excitation amplitude, compensation capacitance, load, and magnetic ring turns on the operating characteristics of the nonlinear resonant circuit are analyzed. The proposed nonlinear resonant wireless power transfer system is constructed and is experimentally studied. Compared with the traditional linear MR‐WPT system, the results show that frequency offset can be effectively suppressed, which ensures efficient transmission performance with the proposed method.

System and methods for wireless power transfer scheduling in a wireless power transfer network

A transmitter in a wireless power transfer network (WPTN) needs to deliver wireless power to a number of wireless power receiver. There can be diverse set of wireless power receivers, for example, Internet of Things devices, smart phones, laptops, etc. The wireless power requirements for receivers vary depending upon their type and state. Commercially deployed WPTNs may also have different subscription plans for users, hence each user’s device should receive wireless power transfer (WPT) service based on the subscribed plan. Usually, a transmitter has to provide service to a number of receivers. Hence, the transmitter needs to have a WPT scheduling method for WPT service delivery. The challenges associated with WPT delivery in a WPTN require a scheduling method that possess the following characteristics: a generalized scheduling method that can work in a setting comprising of heterogeneous receivers, and a scheduling method that can deliver prioritise WPT service, however at the same time it should avoid starvation of lower priority WPT requests. Here, a system and methods for WPT service scheduling are presented. The presented methods possess the above stated characteristics. One of the methods focuses on enhancing a WPT system’s throughput and the other focuses on a receiver device’s remaining charging time. Moreover, both methods avoid starvation of low-priority requests. The presented methods are compared with an existing method, and simulation results demonstrate effectiveness and usefulness of the presented methods.

Analysis of mm-Wave Multi-Stage Rectifier and Implementation

In the mm-wave frequency band, the rectifier’s sensitivity is the bottleneck of a wireless-powered IoT transponder’s distance. At a meter’s distance, the received power is weak, and transistors in a front end of a wireless power receiver operate in the weak inversion region. This article presents a mathematical analysis of the mm-wave multi-stage rectifier in the low-power region. A design methodology of a 57–64-GHz fully integrated eight-stage rectifier with a bulk-drain connection in 40-nm CMOS technology is presented. Parasitic effects on a multi-stage rectifier are analyzed. Based on the analysis, an intrinsic threshold voltage modulation is applied to improve the sensitivity. A tree-type power splitter is also proposed for the RF power signal’s phase balance. With this method, the RF signal arrives at each stage with an equal phase, and its suppression at the output is improved by 16 dB. This mm-wave rectifier achieves −7.1-dBm input sensitivity at 57 GHz with 1-V dc output voltage. The overall sensitivity from 57 to 64 GHz is better than −4.5 dBm. Compared to other mm-wave silicon-based rectifier state of the arts, the proposed mm-wave rectifier achieves better sensitivity while maintaining a compact size.