Receiver Circuit Research Articles

Analysis and Design Consideration of a High Sensitivity Silicon Avalanche Photodiode Receiver for Low Frequency Applications

Silicon avalanche photodiodes (APDs) are designed predominantly for high-speed communication applications, but they can also offer interesting low-light application solutions in lower frequency bands. The design and analysis of a high sensitive silicon avalanche photodiode (APD) receiver for low-light fiber-optical sensor applications is described in this paper. The presented analysis shows relatively significant differences in the overall achievable signal-to-noise and distortion ratio (SINAD) of an optical receiver when using otherwise apparently very similar APDs. Furthermore, to maximize SINAD for the selected APD at a given target total receiver gain, an optimum setting exists between diodes’ internal gain (reverse voltage) and transimpedance gain. Unfortunately, these optimum settings are usually not determinable from the typical specification parameters that are given by APD suppliers, but rather need to be determined experimentally. A circuit with low-noise transimpedance amplifier (TIA) followed by post-amplifier and low-pass filter has, thus, been designed for measurement of the fiber-optical sensor signals with optical power less than 100 pW at 20 kHz bandwidth. The overall SINAD of a receiver circuit is highly dependent on APD excess noise and, therefore, several receiver circuits with different APDs have been built and tested. The receiver responsivity 5.5 GV/W and SINAD of more than 20 dB are achieved with the optimally selected APD.

A Millimeter Wave Loss-Aware Methodology for Switchless PALNA Integrated Circuit Design

Phased array element RF front ends typically use single pole double throw switches or circulators with high isolation to prevent leakage of transmit energy into the receiver circuits. However, as phased-array designs scale to the millimeter-wave range, with high degrees of integration, physical size, and performance degradations associated with switches and circulators can present challenges in meeting system performance and SWAP requirements. This paper provides a loss-aware methodology for analysis and design of switchless transmit/receive (T/R) circuits. The methodology provides design insights and a practical, generally applicable approach for solving the multivariable optimization problem of switchless power amplifier/low-noise amplifier (PALNA) matching networks, which present optimal matching impedances to both the PALNA while maximizing power transfer efficiency and minimizing dissipative losses in each T/R mode of operation. An example design in global foundries 32SOI CMOS at W-band using the proposed methodology is presented. The design achieves simulated maximum power added efficiency of 18% in transmit and noise figure of 7.5 dB in receive at 94 GHz.

A Low Power High Precision Trim-Less Envelope Detector for Fail-Safe Circuit in LVDS Receiver

This brief presents a trim-less precision envelope detector for fail-safe circuit in LVDS receiver. A preamp is proposed using ${g} _{m}$ -constant biasing concept to produce an accurate gain of 9.78 dB across PVT covering the full range of the LVDS input common-mode voltage. The preamp produces a fixed output common-mode voltage of 200 mV across supply voltage variation which reduces its complexity by alleviating the need of a trimming circuit. A unique reference voltage generation of the envelope detector based on level shifted output common-mode voltage accurately compares the output common-mode and negative peak voltages to set the detection threshold. An LVDS receiver adopting the proposed envelope detector was fabricated on a standard 0.13- ${\mu }\text{m}$ CMOS. With a supply voltage of 3.3 V, the envelope detector achieves a voltage trimming precision of 20 mV while only consuming 162 ${\boldsymbol{\mu }}\text{W}$ of power.

Toward self-powered and reliable visible light communication using amorphous silicon thin-film solar cells.

Enhancing robustness and energy efficiency is critical in visible light communication (VLC) to support large-scale data traffic and connectivity of smart devices in the era of fifth-generation networks. To this end, we demonstrate that amorphous silicon (a-Si) thin-film solar cells with a high light absorption coefficient are particularly useful for simultaneous robust signal detection and efficient energy harvesting under the condition of weak light in this study. Moreover, a first-generation prototype called AquaE-lite is developed that consists of an a-Si thin-film solar panel and receiver circuits, which can detect weak light as low as 1 µW/cm2. Using AquaE-lite and a white-light laser, orthogonal frequency-division multiplexing signals with data rates of 1 Mb/s and 908.2 kb/s are achieved over a 20-m long-distance air channel and 2.4-m turbid outdoor pool water, respectively, under the condition of strong background light. The reliable VLC system based on energy-efficient a-Si thin-film solar cells opens a new pathway for future satellite-air-ground-ocean optical wireless communication to realize connectivity among millions of Internet of Things devices.

A compact and energy-efficient ultrasound receiver using PTAT reference circuit

Portable and embedded ultrasound applications require energy-efficient receivers that can operate over a wide range of incident ultrasonic energy. In this paper we show that by directly injecting the ultrasonic signal into a proportional-to-absolute-temperature (PTAT) reference circuit, the pre-amplification and rectification stages used in a conventional ultrasonic receiver can be eliminated which leads to a significant improvement in the system energy-efficiency. The PTAT circuit self-biases itself in accordance to the magnitude of the incident ultrasound pressure signal and is also configured to function as an active diode (with threshold voltage of ≈25 mV) to achieve signal rectification. In this paper we present measurement results obtained from a PTAT-based ultrasound receiver that has been prototyped in a 0.5 μm CMOS process, and we compare the performance to a standard transconductance amplifier (TCA) based design that has also been prototyped in the same process. The improvement in input dynamic range was measured to be 25 dB and sensitivity of the PTAT-based receiver was measured to be 21 Hz/mV when the biasing current is 16.67 nA. We also present the bit-error-rate (BER) performance when the receiver circuit is used for a substrate communications application where ultrasound is used for transmitting and receiving data through an Aircraft grade Aluminum plate.

Secondary-side de-tuning to enable wide-range Inductive Power Transfer for a wrist worn sensor

Powering body worn electronics via inductive power transfer is made more challenging by the poorly constrained relative position of the coils and the consequential wide range of magnetic coupling between them. Somewhat counter intuitively for systems that must operate with coupling factors varying over an order of magnitude it is the design of the receiver side circuits during periods of high coupling that can be most problematic. In this paper a novel low-cost, low power receiver circuit is presented that can automatically compensate for higher coupling by altering the secondary tuning.

$256\times8$ SPAD Array With 256 Column TDCs for a Line Profiling Laser Radar

A receiver circuit for pulsed time-of-flight line profiling laser radar has been designed in $0.35\mu \text {m}$ CMOS technology. The receiver consists of a line detector array with $256\times 8$ SPADs with a pitch of $41.6\mu \text {m}$ . The diameter of the SPAD’s active area is $25.6\mu \text {m}$ , which gives a fill factor of 0.35. Each column has 8 SPADs and a TDC with a range and resolution of 640 ns and 20 ps, respectively. The TDCs are based on the Nutt interpolation method where cyclic converters are utilized as fine converters. A compact demonstrator system has been built with a horizontal FOV of about 37°, which gives a column-wise angular resolution of about 0.15°. This solid-state system uses a pulsed laser diode with cylindrical transmitter optics to illuminate the full FOV of the receiver with a single laser pulse. The system can measure distances up to 30 m @ 28 fps with an accuracy and precision of few millimeters in typical indoor lighting conditions. Outdoors, in direct sunlight conditions, the measurement range is decreased to 5 m. Outdoor range, however, can be increased if frame rate is lowered and more laser shots are accumulated per frame.

Li-Fi BASED REAL TIME VIDEO TRANSMISSON FOR PATIENT MONITORING SYSTEM

The aim of this work is to achieve live surveillance of the patient using LI-FI (light fidelity). Lifi is an advanced and promising technology can be used in many medical applications. In this paper, a prototype of live video broadcast using LEDs is proposed. The prototype presented transfers the data with single LED, and is capable of illumination as well as data broadcast. Whole process is kick started by converting analog signal into digital form in transmitter section. LM359 IC amplifies video signal with two inverting amplifiers which possess high gain bandwidth and allows high frequencies and it is coupled to LED which accelerates the transmission process and it’s geared at high speed by receiving the high frequency video signal in digital form by a photo detector. The output from the receiver circuit is analog output given to television module using a RCA cable.

Wireless power transfer using the concept of magnetic coil resonant system

Long life lithium ion batteries and methanol fuel cells have been persuaded as ways to make the electrical components more mobile, consumers expectations are still far from being met due to the added weight and expenses for battery replacement. The discovery of wireless power transfer as a new option, and holds great promise to leave the oversized battery. The design of wireless power transfer applies the concept of Magnetic Coil Resonant System (MCRS). The concept of MCRS is similar with a function of an antenna to transfer the power from one point to another. Multisim13.0 software is applied to predict the performance of the proposed MCRS. This software simulation is useful to estimate the output wave on the virtual oscilloscope and to obtain the reading of output voltage from the virtual multimeter. The transmitter side contains power supply, transmitter oscillator circuit and transmitter magnetic coil. Transmitter circuit convert DC to AC waveform and the receiver circuit convert AC to DC voltage. The DC Source that connected to Transmitter was provided by the DC source regulator acts as DC source to adjust Voltage and Current separately. The project show the efficiency of the wireless power transfer with different coil diameter and a distance between the transmitter and receiver coil. At a distance of 15 cm, power are successfully transmitted as it is indicated by the LED light to turn on. The increment of size in coil diameter has given a higher power and longer coverage distance for wireless transfer power.

Data Communication Security Issues of Wi-Fi over Li-Fi

Visible Light Communications (VLC) system is called Light Fidelity One such example, analog data is passed to a LED (Light-Emitting Diode) bulb (using signal processing technology), after that it transmits data (which is implanted in its beam) to the detector or photodiode. The small commutes in the brisk feeble of LED bulbs is modulated by the receiver circuit into electrical signal. The signal is then reversed into a duplex data runnel that could be recognized in the same way that of audio, video and web programs that run on devices that has internet enabled. Wi-Fi is vulnerable to breaches involving various security issues such as Rouge Access Points, Denial of Service, Wireless Trespasser, Data Interruption, End point attacks etc. To overcome such restrictions, this paper proposes application level substructure for data communication using Li-Fi (Light Fidelity) Technology. By using LED lights as a transmission medium, the indoor wireless communication is achieved in much faster rate than the one Wi-Fi (Wireless Fidelity) can provide.

Preliminary design and characterization of a low-cost and low-power visible light positioning system.

Designs and results for a low-power and economical fingerprint visible light positioning (VLP) system are discussed in this paper. A system using four white LEDs and one photodiode was deployed. The LEDs are independently controlled and modulated by individual transmitter circuits, removing the requirement for a large, expensive signal generator. The receiver circuit filters and converts the received signal to DC, allowing a simple microcontroller to save the received signal. We propose the creation of a fingerprint database by recording signal data, fitting a two-dimensional Gaussian distribution to the data, and then generating the fingerprint database for all positions in the evaluation system. System positioning accuracy of 13.44+/-0.36 mm was observed, corresponding to a relative error of 2.8% with respect to the system dimensions. This result presents an improvement on positioning accuracy for fingerprint positioning VLP systems, which build their own transmitters.

Short-Range Quality-Factor Modulation (SQuirM) for Low Power High Speed Inductive Data Transfer

Wireless data telemetry for implantable medical devices (IMDs) has, in general, been limited to a few Mbps, and used for applications such as transmitting recordings from an implanted monitoring device, or uploading commands to an implanted stimulator. However, modern neural interfaces need to record high resolution potentials from hundreds of neurons; this requires much higher data rates. While fast wireless communication is possible using existing standards such as WiFi, power consumption demands are far too high for IMDs. Short range inductive link based telemetry, in particular impulse-based systems such as pulse-harmonic modulation (PHM), have demonstrated transfer speeds of up to 20 Mbps with a small power budget. However, these systems require complex and precise circuits, making them potentially susceptible to inter-symbol-interference. This work presents a new method named Short-range Quality-factor Modulation (SQuirM), which retains the low power consumption and high data rate of PHM, while improving the resilience of the system and simplifying the circuit design. Transmitter and receiver circuits were fabricated using 0.35 ${\mu }m$ CMOS. The circuits were capable of reliably transceiving data at speeds of up to 50.4 Mbps, with a BER of $ , and a transmitter energy consumption of 8.11 pJ/b.

Nanoscale spin-wave wake-up receiver

We present the concept of a passive spin-wave device which is able to distinguish different radio frequency pulse trains and validate its functionality using micromagnetic simulations. The information is coded in the phase of the individual pulses which are transformed into spin-wave packets. The device splits every incoming packet into two arms, one of which is coupled to a magnonic ring which introduces a well-defined time delay and phase shift. Since the time delay is matched to the pulse repetition rate, adjacent packets interfere in a combiner, which makes it possible to distinguish simple pulse train patterns by the readout of the time-integrated spin-wave intensity in the output. Due to its passive construction, this device may serve as an energy-efficient wake-up receiver used to activate the main receiver circuit in power critical internet of things applications.

Interconnect Routing for Large-Scale RSFQ Circuits

The increasing complexity of modern rapid single flux quantum (RSFQ) circuits has made on-chip signal routing, an issue of growing importance. In this paper, several methods for routing large-scale RSFQ circuits are described, and a process is presented for determining when to use passive microstrip transmission lines (PTL) and active Josephson transmission lines (JTL). The effect of the size of the JTL inductor and Josephson junctions on the length of a JTL chain for a target delay is also discussed. The dependence of the JTL inductance on the physical layout is evaluated, and the effects of the primary PTL parameters on delay are characterized. A novel PTL driver and receiver configuration is also proposed. Tradeoffs among the number of JJs, inductance, and length of a PTL stripline in the receiver and driver circuits are reported. The energy dissipation is evaluated for two different interconnects. A tradeoff between the proposed PTL circuits and an optimized JTL in terms of energy dissipation and delay is discussed. Guidelines for choosing the optimal element values are determined, and a simulated bias margin of ±29% for the bias current of the proposed receiver operating at 20 GHz in a 10 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> technology for a 1-mm transmission line is achieved. Summarizing, guidelines and design tradeoffs appropriate for automated layout and synthesis are provided for driving long interconnect in SFQ VLSI circuits.

Superconducting optoelectronic loop neurons

Superconducting optoelectronic hardware has been proposed for large-scale neural computing. In this work, we expand upon the circuit and network designs previously introduced. We investigate circuits using superconducting single-photon detectors and Josephson junctions to perform signal reception, synaptic weighting, and integration. Designs are presented for synapses and neurons that perform integration of rate-coded signals as well as detect coincidence events for temporal coding. A neuron with a single integration loop can receive input from thousands of synaptic connections, and many such loops can be employed for dendritic processing. We show that a synaptic weight can be modified via a superconducting flux-storage loop inductively coupled to the current bias of the synapse. Synapses with hundreds of stable states are designed. Spike-timing-dependent plasticity can be implemented using two photons to strengthen and two photons to weaken the synaptic weight via Hebbian-type learning rules. In addition to the synaptic receiver and plasticity circuits, we describe an amplifier chain that converts the current pulse generated when a neuron reaches threshold to a voltage pulse sufficient to produce light from a semiconductor diode. This light is the signal used to communicate between neurons in the network. We analyze the performance of the elements in the amplifier chain to calculate the energy consumption per photon created. The speed of the amplification sequence allows neuronal firing up to at least 20 MHz, independent of connectivity. We consider these neurons in network configurations to investigate near-term technological potential and long-term physical limitations. By modeling the physical size of superconducting optoelectronic neurons, we calculate the area of these networks. A system with 8100 neurons and 330 430 total synapses will fit on a 1×1cm2 die. Systems of millions of neurons with hundreds of millions of synapses will fit on a 300 mm wafer. For multiwafer assemblies, communication at light speed enables a neuronal pool the size of a large data center (105m2) comprised of trillions of neurons with coherent oscillations at 1 MHz.

A low-power reference-less clock/data recovery for visible light communication devices requiring low data throughput

In this study a reference-less clock and data recovery (CDR) is designed and developed for the low speed visible light communication system based Internet of Things (IoT) tags. Design system incorporates an off-chip photodiode and an integrated-on chip front-end receiver with the reference-less CDR. For an IoT tags low power consumption, low supply voltage, and small area are the major design constraint. Considering these constraints, the circuit of the front-end receiver incorporate the near-threshold cascode current mirror based transimpedance amplifier, low pass filter and a comparator. On the other-hand, low power all-digital phase locked loop-based reference-less CDR is design herein with a modified loop filter, auto tune digital control oscillator and auto duty cycle adjustment circuit. The circuit is implemented in an integrated chip with area of 0.728 mm2 via TSMC 180 nm process. Experimental measurement results of the tapeout chip shows that the phase noises are − 39.54 dBc/Hz @ 1 kHz, − 80.35 dBc/Hz @ 10 kHz and − 92.26 dBc/Hz @ 100 kHz. The measured jitter in the recovered clock is 3.312 ns (0.0033 UI). At 1 Mbps, the measured total power consumption is 5.58 μW. The achieve results shows that the implemented circuit in this study highly support the commercial low data rate based optical wireless sensing nodes for IoT tags.

Design of Magnetic Induction Based Energy-Efficient WSNs for Nonconventional Media Using Multilayer Transmitter-Enabled Novel Energy Model

Wireless sensor networks (WSNs) are used in nonconventional media such as underground and underwater environment for applications concerning sensing, intrusion detection, monitoring, and exploration. Traditional techniques of communication like electromagnetic are not suitable for nonconventional media, mainly because of high path loss and thus being impractical. In underwater environment, the majority of the research work is based on acoustic communication. However, it faces many challenges like dynamic channel behavior, low data rate, and high propagation delay. Magnetic induction (MI)-based communication is a recently explored technique for nonconventional media applications. This communication method exhibits several promising characteristics such as predictable and constant channel behavior, negligible propagation delay, sufficiently large communication range with high data rate, and stealth underwater operations. In this paper, four possible compensation circuits and multilayer coil structure are suggested for better design of MI transceiver. Herein, the amount of power received by the receiver circuit mainly depends on the structure of the coil used in the transceiver and the type of media through which the signal propagates. Multilayer coil structure is preferred for the proposed design since it performs better than its single-layer counterpart. A novel energy model for MI-based communication link in nonconventional media is proposed. This model describes energy dissipation in the transceiver circuit for MI communication. An analytical model of optimal clustering is also performed with different positions of base station to elaborate the application of the proposed energy model. Performance analysis is also carried out in dry sand, freshwater, and seawater conditions of nonconventional media.

A Modified Wireless Power Transfer System for Medical Implants

Wireless Power Transfer (WPT) is a promising technique, yet still an experimental solution, to replace batteries in existing implants and overcome the related health complications. However, not all techniques are adequate to meet the safety requirements of medical implants for patients. Ensuring a compromise between a small form factor and a high Power Transfer Efficiency (PTE) for transcutaneous applications still remains a challenge. In this work, we have used a resonant inductive coupling for WPT and a coil geometry optimization approach to address constraints related to maintaining a small form factor and the efficiency of power transfer. Thus, we propose a WPT system for medical implants operating at 13.56 MHz using high-efficiency Complementary Metal Oxide-Semiconductor (CMOS) components and an optimized Printed Circuit Coil (PCC). It is divided into two main circuits, a transmitter circuit located outside the human body and a receiver circuit implanted inside the body. The transmitter circuit was designed with an oscillator, driver and a Class-E power amplifier. Experimental results acquired in the air medium show that the proposed system reaches a power transfer efficiency of 75.1% for 0.5 cm and reaches 5 cm as a maximum transfer distance for 10.67% of the efficiency, all of which holds promise for implementing WPT for medical implants that don’t require further medical intervention, and without taking up a lot of space.

Smartwatch Strap Wireless Power Transfer System With Flexible PCB Coil and Shielding Material

In this paper, we designed and demonstrated a smartwatch strap wireless charging system for the first time. First, we designed a flexible printed circuit board (PCB) coil, shielding material, and receiver (Rx) circuit in a watchstrap. In the design process, we proposed a model for the flexible PCB coil with a bending radius of 40 mm and shielding materials. We used a flexible PCB coil that has 215 μ m thickness with dimensions of 54.5 × 16 mm. In addition, ferrite core and sheet are applied on the transmitter (Tx) and Rx coils. We verified the proposed model through a three-dimensional (3-D) electromagnetic (EM) simulation and measurement in the frequency and time domains. The proposed flexible PCB coil inductance modeling results showed 7.5% and 3.4% errors when compared to the 3-D EM simulation and measurement results, respectively. Furthermore, we demonstrated the smartwatch strap wireless charging system using an LG Watch Urbane. A resonance frequency of 100 kHz with the series–series tuning topology is used in accordance with the Qi specifications. Finally, we achieved 30% dc–dc power transfer efficiency and exposed magnetic field of 270 mG, 1 cm away from the system through measurements.

Wireless Power Transfer Solutions and Their Effectiveness [Georgia Institute of Technology

My research focuses on the problems related to the creation of a wireless power transfer system designed for energy transmission at a distance of at least one meter. The project was created to provide data for the advancement of wireless power, specifically via radio frequency transmission. Previous research efforts that attempted to develop this technology have run into unforeseen obstacles that have hindered its consumer and commercial adoption. This research will yield more information into those barriers and what can be done to assist wireless power in its future development as an applied technology. To begin producing data, a wireless power system first must be created. The central design element of the transmitter was a Texas Instruments PLL and integrated VCO wideband frequency synthesizer programmed to output a 3.6GHz sine wave. That signal was then passed into a GaN amplifier integrated circuit from Analog Devices and finally transmitted via a wideband Molex antenna. The receiver circuit was much simpler, simply consisting of a second Molex antenna and a bridge rectifier circuit to convert the AC signal to DC. A multipurpose ATmega328 programs the frequency synthesizer on the transmitter and reads the voltage and current from the receiver with its integrated ADC. The research is currently still in progress, but the data that has been accumulated shows that transmission is possible but with lower power yields than initially expected. The maximum range of received power was one meter, but because the transmitted voltage and current did not meet the calculated values, the project must have reached one or more of the unknown obstacles in wireless power design. To isolate and learn more about them, the project will be revised to gather more data. It will change into different models of power transfer and be tested for their effectiveness for the benefit of future research in this topic.