Wide Input Range Research Articles

91.6% efficient hybrid DC-DC buck converter with wide programmable conversion range

A new power-efficient and wide input range hybrid dc-dc buck regulator is proposed in this paper. The proposed regulator could be used in different applications that needs power and area efficient switching regulators like battery chargers, IoT, wearable and hearable technologies. This regulator employs an inductor positioned at the lower current path to reduce the DC component of the inductor current. This significantly decreases inductor losses. The inductor is followed by a switched capacitor circuit used to deploy the step-down function despite the inductor position. Detailed analysis of the proposed regulator architecture with emphasis on the efficiency, power density, and output ripples are presented and verified by simulations. The proposed converter regulates an output voltage of 650 mV for an input voltage range of 0.75–1.8 V. The regulator can achieve peak efficiency of 91.6%, supplies a maximum load current of 0.5 A and is implemented using 0.18 μm CMOS technology.

The specifics of selected agricultural commodities in international trade

Purpose. This paper evaluates the involvement of three selected agricultural commodities (rice, coffee and soya) in international trade. The aim is to analyze the specification of foreign trade in selected commodities and assess their different significance between representations in domestic markets and exports. This article will also assess other contexts related to international trade in these three commodities, including the negative effects on their trade. Based on the set goal, a research question was asked which evaluates the different position of the examined agricultural commodities on world export markets in relation to domestic consumption.
 Methodology / approach. The theoretical anchoring of the issue under study are the approaches taken to international economic relations with the emphasis on the specific features of agricultural trade. The methodological framework of the present study is based on the systematic analysis of the spatial distribution of production capacities, the territorial analysis of exports and imports within the world agricultural market and qualitative evaluation of the specifics of selected export commodities and their role in the economy of countries, including labour market importance and in the possibilities of their use.
 Results. The paper presents the results of the involvement of the rice, coffee and soya in international trade analysis. Most rice production is consumed on domestic markets. Unlike rice, most of the coffee produced is exported and less is consumed within the growing countries themselves. Although domestic coffee consumption is increasing, more than 70% of world production is exported. Soya bean production has increased significantly over the past 50 years as a result of the rising demand for animal feedstuff and biofuels. Almost three quarters of soya bean production is consumed as feedstuff.
 Originality / scientific novelty. The main contribution of the article is in the application level the elaboration of a comparative view of three selected agricultural commodities. At the theoretical level of the study, it represents a contribution to the discussion within the approaches to the organization of global agricultural trade, the interdependence of economic policies of states, trade ties and the impact on labour markets in relation to production. Agricultural commodities remain an important item in world international trade. However, their share in the total volume is gradually declining. They play an important role in the maintenance of individual countries, but at the same time they are of great economic importance, although we can also mention the less positive aspects of their production, including their impact on the environment. At the same time, it is necessary to realize that this sector is essential for human survival and also that agriculture is important from the point of food security for the population, which can contribute to and increase the level of agricultural protectionism (resilience to world market disruptions or uncontrolled import of genetically modified (GM) food and the transmission of animal diseases). Agriculture is one of the most sensitive economic sectors in the world. Nevertheless, agricultural exports have several economic benefits, including stimulating a wide range of agricultural-related industries, transport suppliers, processing and farm inputs.
 Practical value / implications. The production of agricultural commodities is of great importance to the economies of individual states, where it contributes to the creation of direct, indirect and induced jobs. The agrarian sector is a key sector, especially for less developed countries. The analysis confirmed the high tradability of all commodities examined and is documented by their involvement in the international division of labour in the global projection.

Design of Pulse Signal Acquisition System of Adaptive Wide Dynamic Range Based on ADS125H02

In order to solve the problem of wide input range of photocurrent, aiming at the shortage of existing pulse signal acquisition system, an adaptive pulse signal acquisition system based on ADS125H02 is designed, which has high collection accuracy, low noise, anti-interference, wide input range, high integration, etc. The measurement range of the system can reach ±10 V, and the accuracy is 0.009 μV. Experimental tests show that the design of the system can extract weak pulse signals, and has good practicality.

Systematic review and grounded theory as a mixed method to develop a framework for counselling skills competencies

AbstractThis methodology paper presents how the application of grounded theory (GT) allowed the incorporation of additional data sources from what began as a systematic literature review (SLR) aimed at developing a counselling skills competencies framework for non‐career counsellors who provide counselling in a variety of care settings. This involved inclusion of purposive research material from experts with a wide range of relevant experience and critical input compensating for the limitations of the systematic review. GT provided the necessary analytic steps, and the paper discusses how the application of the constant comparative analysis procedure assured in‐depth analysis of the data from the systematic review, empirical data suggested by expert participants, researcher reflexivity, and critique and feedback from independent experts. Overall, this mixed‐methods approach enabled an expansion of relevant data and led to the construction of a framework for counselling skills organised into five key categories. A core group of practitioners and academics (CG) engaged in open and axial coding, holding in mind the goals of the project. Critical assessment and scrutiny through dialogue and reflection achieved saturation and agreement of the final framework. This meticulous process was inclusive of the views of experts in the field of counselling and led to an integrated framework of counselling skills for individuals in various care settings (nursing homes, NHS and social care services, charitable community projects, etc.). The paper shows that grounded theory allowed expansion of the data field and demonstrates how this approach added rigour and reliability to the developing framework.

A wide input range energy harvesting system for AM broadcast with capacitor load

A high efficiency, wide input range radio frequency (RF) energy harvesting system with capacitor load is presented, applied for harvesting the energy from amplitude modulation (AM) broadcast. The chip is fabricated in 55 nm complementary metal-oxide-semiconductor (CMOS) technology, and the active chip area is 1.63 mm2. The number of stages of the rectifier is reconfigurable to improve the power efficiency when the voltage across the capacitor changes during charge accumulation. A dual-path rectifier with the switch in parallel is adopted to extend the input power range of high power efficiency (>20%). Meanwhile, to achieve the high sensitivity, a 4 nA static current-voltage reference supplying for low-power loop controller is also proposed. The measurement results show that the average power efficiency is improved up to 48.7% when the capacitor load is charged from 0 to 2 V and at least 6.3% improvement compared to fixed stages rectifier. The high power efficiency range is improved by 20 dB, while the single-path reconfigurable rectifiers can only maintain the high power conversion efficiency range for a 14-dB range. The measured RF input power sensitivity is −34.2 dBm for a 1 V output voltage.

Incorporating Universal Design into Tsunami Modeling Results for Cascadia Subduction Zone Faults to Create an Inundation Map and Universally Designed Evacuation Map for Port Angeles, WA

Current tsunami hazard inundation and evacuation maps in the Puget Sound are based primarily on Cascadia and Seattle fault tsunamis. The standard evaluation process for tsunami impacts focuses on elevation and hypothetical fault rupture of known and predicted earthquakes. However, there are several known tsunami deposits in the Puget Sound that are not from Cascadia or Seattle fault tsunamis, potentially from other faults within the region, that could affect tsunami mitigation. Work to understand newly discovered crustal deformation and faults in Puget Sound is ongoing, therefore evacuation and inundation maps need to be updated to include these new faults and integrate universal design more broadly. Methods involved using GeoClaw software to map tsunamis from the Cascadia Subduction Zone (CSZ), Leech River fault (LRF), and Utsalady Point fault (UPF). Modeled tsunamis determined the overall inundation of Port Angeles, Washington through a wide range of earthquake inputs of magnitude, proximity, and recurrence. The output simulations were evaluated with key components of universal design to create a new tsunami hazard map. Comparison between the universal design-based map to current the tsunami hazard map allowed for an evaluation of the current evacuation map. This evaluation can improve the assessment of bridges and other evacuation mechanisms. This research can contribute to future tsunami hazard map revisions saving lives, can help with emergency management planning, and spur reevaluating evacuation plans within the tsunami impact area.

A CMOS Adaptive 433/900 MHz Differential RF Power Harvester with Wide-Dynamic Range for Wireless Powering

A wide-dynamic range high-efficiency differential RF-to-DC power converter for wireless power transfer (WPT) applications is presented. The architecture offers high power conversion efficiency (PCE) over a wide range of input powers by employing cross-coupled high-threshold rectifying devices with stacking diodes. The proposed rectifier uses the adaptive biasing technique to control the rectifying devices’ conduction and minimizes the leakage current of the feedback diodes by utilizing the dynamic body biasing. Compared to the conventional cross-coupled rectifier, the proposed rectifier has a [Formula: see text] dynamic range. A prototype of the proposed rectifier is implemented in 65-nm CMOS technology and occupies an area of 0.0148[Formula: see text]mm2. The rectifier achieves [Formula: see text][Formula: see text]dBm sensitivity for 1[Formula: see text]V output and a 79.4% peak PCE. A dynamic range of 17.3[Formula: see text]dB is achieved at the 433[Formula: see text]MHz in the Industrial Scientific Medical band (ISM band) with a 100-K[Formula: see text] load. Furthermore, the proposed design offers a peak PCE of 62.6% and a wide dynamic range of 16.1[Formula: see text]dB at the UHF 900[Formula: see text]MHz band with a load resistance of 100-K[Formula: see text].

Plasticity of Multidimensional Receptive Fields in Core Rat Auditory Cortex Directed by Sound Statistics

Sensory cortical neurons can nonlinearly integrate a wide range of inputs. The outcome of this nonlinear process can be approximated by more than one receptive field component or filter to characterize the ensuing stimulus preference. The functional properties of multidimensional filters are, however, not well understood. Here we estimated two spectrotemporal receptive fields (STRFs) per neuron using maximally informative dimension analysis. We compared their temporal and spectral modulation properties and determined the stimulus information captured by the two STRFs in core rat auditory cortical fields, primary auditory cortex (A1) and ventral auditory field (VAF). The first STRF is the dominant filter and acts as a sound feature detector in both fields. The second STRF is less feature specific, preferred lower modulations, and had less spike information compared to the first STRF. The information jointly captured by the two STRFs was larger than that captured by the sum of the individual STRFs, reflecting nonlinear interactions of two filters. This information gain was larger in A1. We next determined how the acoustic environment affects the structure and relationship of these two STRFs. Rats were exposed to moderate levels of spectrotemporally modulated noise during development. Noise exposure strongly altered the spectrotemporal preference of the first STRF in both cortical fields. The interaction between the two STRFs was reduced by noise exposure in A1 but not in VAF. The results reveal new functional distinctions between A1 and VAF indicating that (i) A1 has stronger interactions of the two STRFs than VAF, (ii) noise exposure diminishes modulation parameter representation contained in the noise more strongly for the first STRF in both fields, and (iii) plasticity induced by noise exposure can affect the strength of filter interactions in A1. Taken together, ascertaining two STRFs per neuron enhances the understanding of cortical information processing and plasticity effects in core auditory cortex.

Battery Charger with Bidirectional Power Transmission

The gradual reduction in price of electric batteries contributes to their wider use in autonomous and centralized power supply systems as a backup source of electricity and increase the share of electric vehicles. In the paper the conditions for increasing the efficiency of electric vehicle batteries, in particular in the framework of the concept of V2G (Vehicle to Grid) as a drive for the organization of autonomous power supply systems are analyzed. It is shown that this is possible only with the simple integration of batteries into the system, flexibility, and a wide range of modes that have to be provided by unified charge-discharge devices. Such charging devices have to have such features: a wide range of input and output voltage parameters; correction of the input power factor; the ability to take the maximum power from renewable energy sources; high energy efficiency. A review of possible topologies for a charger with bidirectional power transmission and a bridge converter with soft switching of transistors at zero voltage, which has a high efficiency, galvanic isolation and the ability to correct the shape of the current. The modes of operation of the converter are analyzed and conditions of soft switching is obtained. It is shown that soft switching is valid for current that is not less than minimal one. Efficiency of the converter with soft commutation is compared with a similar converter with rigid commutation of transistors. It is shown that static losses in converter with soft commutation it higher than in the rigid one. So, the proposed converter should be used if the increase in static losses is compensated by the lack of dynamic losses. Additional feature of the converter is that the regulation of the output voltage of the converter with soft switching is carried out according to the law of frequency-pulse modulation with a constant pause duration, where the pause duration is determined by the period of resonant processes of the converter. The model of the converter in Matlab Simulink is built and it is shown that the efficiency of the proposed converter topology is 10-15% higher, which together with the possibility of sinusoidal current with THD ≈ 20% and two-way transmission energy indicates the feasibility of its use as a charger for electric vehicles under the concept of V2G. However, it should be noted that the use of LCL filter creates a phase shift between voltage and current and degrades the THD value. To improve the shape, it is possible to use specialized laws of modulation [or to use modular converters, which allow to obtain a continuous current shape and reduce the volume of the filter.

Phytoplankton biomass, dissolved organic matter, and temperature drive respiration in whole lake nutrient additions

AbstractLake respiration is supported by a mixture of autochthonous and allochthonous resources, but the relative significance and interaction of these sources are uncertain across gradients of primary production and organic matter inputs. We manipulated autochthonous resources by adding inorganic nitrogen and phosphorus to two lakes during three summers and monitored a third reference lake. Allochthonous resources were measured as fluorescent dissolved organic matter (FDOM). In the reference and two experimental lakes, daily estimates of respiration were made from continuously deployed oxygen sensors. Daily mean values of temperature and FDOM were determined from high‐frequency measurements along with daily measures of chlorophyll a, an index of phytoplankton biomass. We analyzed time series of respiration and tested models that used combinations of the independent variables chlorophyll, FDOM, and temperature. The best models included all three of the independent variables. Respiration increased twofold over the temperature range of 14.5–28.6°C. Respiration increased in association with phytoplankton blooms caused by the nutrient additions, but did not track blooms closely, because of large day‐to‐day variability. Respiration varied positively with FDOM that was primarily allochthonous and differed among lakes and years. We did not detect an interaction between chlorophyll and FDOM despite the large number of observations and range of chlorophyll and FDOM. Hydrologic, climatic, and land use changes are altering temperature and inputs of nutrients and organic matter to lakes. Our results indicate that these changes may lead to linear responses in ecosystem processes like respiration for the wide range of inputs represented in this study.

Real time prediction of internal temperature of heat generating bodies using neural network

Heat generating bodies are typically immersed in surrounding fluid that acts as a coolant, either though forced or natural convection. For safe operation, the heat generated should be transferred to the surrounding fluid at a rate that is required to maintain the internal temperature below a critical value. In cases such as nuclear fuel rods and lithium-ion batteries, it is very difficult to install conventional measuring devices like thermocouples and pyrometers inside the heated equipment to monitor the internal operating temperature and trigger warnings when it reaches the critical point. It is however relatively easy to measure the temperature of the surrounding coolant in which they are immersed. From these measurements, the temperature distribution inside the equipment can be estimated using inverse techniques. Inverse analysis can generate data that provides insight into thermal behavior of equipment and help detect overheating events so that corrective action may be taken. A generic and novel framework for conducting inverse analysis to predict internal temperature of cylindrical heat generating bodies has been developed and validated with experimental setup. Simulation-based inverse analysis techniques require large computation effort for complex geometries and high-fidelity models, which make them impractical for real time applications. To circumvent this, a neural network-based model was utilized for predicting temperature inside the system in lieu of a high-fidelity simulation model. Training data was generated through high fidelity simulation using OPENFOAM with an axi-symmetric model. The approach was applied to an experimental setup using a cartridge heater as a representation of a heat generating rod. The coolant height and temperature measured in fluid region was given as input to a trained neural network model to predict surface temperature and inside temperature of the heat generating rod. Inversely predicted temperature was in good agreement with experiment data over wide range of power input. In addition, temperature obtained from this model was used to display in real time on an augmented reality device, which could allow field workers to easily monitor in the field. Novelty of this framework is that the measured coolant temperature in which the heat generating body is immersed is used as input for the rapid and accurate inverse prediction of internal temperature.

A Fast and Efficient Single-stranded Genomic Library Preparation Method Optimized for Ancient DNA.

We present a protocol to prepare extracted DNA for sequencing on the Illumina sequencing platform that has been optimized for ancient and degraded DNA. Our approach, the Santa Cruz Reaction or SCR, uses directional splinted ligation of Illumina’s P5 and P7 adapters to convert natively single-stranded DNA and heat denatured double-stranded DNA into sequencing libraries in a single enzymatic reaction. To demonstrate its efficacy in converting degraded DNA molecules, we prepare 5 ancient DNA extracts into sequencing libraries using the SCR and 2 of the most commonly used approaches for preparing degraded DNA for sequencing: BEST, which targets and converts double-stranded DNA, and ssDNA2.0, which targets and converts single-stranded DNA. We then compare the efficiency with which each approach recovers unique molecules, or library complexity, given a standard amount of DNA input. We find that the SCR consistently outperforms the BEST protocol in recovering unique molecules and, despite its relative simplicity to perform and low cost per library, has similar performance to ssDNA2.0 across a wide range of DNA inputs. The SCR is a cost- and time-efficient approach that minimizes the loss of unique molecules and makes accessible a taxonomically, geographically, and a temporally broader sample of preserved remains for genomic analysis.

3–12-V Wide Input Range Adaptive Delay Compensated Active Rectifier for 6.78-MHz Loosely Coupled Wireless Power Transfer System

This paper presents a wide input range active rectifier using a bipolar-CMOS-DMOS (BCD) process with a high voltage conversion ratio (VCR) and high power conversion efficiency (PCE). The proposed rectifier ensures safe and robust operation under large input voltage variations, which can be caused by changes in the magnetic coupling or loading conditions. It supports an input voltage range 3-12 V with the adaptive delay-compensated active operation of the power switches. An active signal clamper and voltage-time hybrid gate control circuit with two compensation loops was proposed for the optimal gate transition of low-side NMOS switches. For high-side PMOS switches, a fully integrated low-power-consuming high-side driver is proposed to replace the conventional high-side gate driving structure. The proposed active rectifier was fabricated through a TSMC 0.18 μm BCD process. The measurement results show that the proposed rectifier achieves stable and well-delay-compensated active operation, resulting in a high VCR and PCE with a wide output power range from 4.5 to 288 mW. Peak VCR and PCE of 96.8% and 93.7%, respectively, were achieved.

SP3 Protocol for Proteomic Plant Sample Preparation Prior LC-MS/MS.

Quantitative protein extraction from biological samples, as well as contaminants removal before LC-MS/MS, is fundamental for the successful bottom-up proteomic analysis. Four sample preparation methods, including the filter-aided sample preparation (FASP), two single-pot solid-phase-enhanced sample preparations (SP3) on carboxylated or HILIC paramagnetic beads, and protein suspension trapping method (S-Trap) were evaluated for SDS removal and protein digestion from Arabidopsis thaliana (AT) lysate. Finally, the optimized carboxylated SP3 workflow was benchmarked closely against the routine FASP. Ultimately, LC-MS/MS analyses revealed that regarding the number of identifications, number of missed cleavages, proteome coverage, repeatability, reduction of handling time, and cost per assay, the SP3 on carboxylated magnetic particles proved to be the best alternative for SDS and other contaminants removal from plant sample lysate. A robust and efficient 2-h SP3 protocol for a wide range of protein input is presented, benefiting from no need to adjust the amount of beads, binding and rinsing conditions, or digestion parameters.

Design of a new voltage reference source

Current reference is a very important module in analog circuits. The main purpose of this design is to provide a stable reference voltage for a switch magnetism-sensing circuit. Because of the inherent characteristics of the circuit, the reference voltage is set to 3.3V. In this paper, the reference voltage source is designed to have a wide input range, a stable output and a good temperature characteristic. In this paper, the simulation results of the reference voltage and the complete design layout are described, and a current reference is achieved, which is independent of process, voltage and temperature, with little area increases only. The simulation results based on a 4 μm 25 V bipolar process verify the correctness of the theoretical analysis and the feasibility of the proposed methods.

A full input range, 1–1.8 V voltage supply scalable analog voltage comparator in 180nm CMOS

ABSTRACT A voltage supply scalable analog voltage comparator for a wide input range is presented in this paper. A digital gate-based methodology is used to design the comparator in order to extend the use of automation in the analog designs. Therefore, the proposed comparator is enormously cost-effective, reduces the time-to-market, scalable to newer technologies, and more immune to process variations than the conventional CMOS analog voltage comparators. The comparator is designed using Semi-Conductor Laboratory (SCL) 180 nm digital CMOS technology at a supply voltage of 1.8 V. The power consumption of the proposed comparator is 160 µW approximately with total delay and offset voltage of 1.63 ns and 4.28 mV, respectively. Also, 4-bit and 5-bit flash ADC is designed as an application. The measured values of DNL/INL are ± 0.4/± 0.4 LSB and 0.42/± 0.6 LSB for 4-bit and 5-bit, respectively.

Local Homeostatic Regulation of the Spectral Radius of Echo-State Networks.

Recurrent cortical networks provide reservoirs of states that are thought to play a crucial role for sequential information processing in the brain. However, classical reservoir computing requires manual adjustments of global network parameters, particularly of the spectral radius of the recurrent synaptic weight matrix. It is hence not clear if the spectral radius is accessible to biological neural networks. Using random matrix theory, we show that the spectral radius is related to local properties of the neuronal dynamics whenever the overall dynamical state is only weakly correlated. This result allows us to introduce two local homeostatic synaptic scaling mechanisms, termed flow control and variance control, that implicitly drive the spectral radius toward the desired value. For both mechanisms the spectral radius is autonomously adapted while the network receives and processes inputs under working conditions. We demonstrate the effectiveness of the two adaptation mechanisms under different external input protocols. Moreover, we evaluated the network performance after adaptation by training the network to perform a time-delayed XOR operation on binary sequences. As our main result, we found that flow control reliably regulates the spectral radius for different types of input statistics. Precise tuning is however negatively affected when interneural correlations are substantial. Furthermore, we found a consistent task performance over a wide range of input strengths/variances. Variance control did however not yield the desired spectral radii with the same precision, being less consistent across different input strengths. Given the effectiveness and remarkably simple mathematical form of flow control, we conclude that self-consistent local control of the spectral radius via an implicit adaptation scheme is an interesting and biological plausible alternative to conventional methods using set point homeostatic feedback controls of neural firing.

Volatile Photovoltaics: Green Industrialization, Sacrifice Zones, and the Political Ecology of Solar Energy in Germany

The development of solar energy has been depicted as a paradigmatic break in unsustainable global growth, largely because it is framed as an innovation with minimal carbon emissions. On the contrary, drawing on literatures from spatial justice and political ecology, including on authoritarian populism, this article analyzes the rise and fall of the solar industry and the associated failures of “green industrialization” in Bitterfeld, East Germany—an area that is characterized by political, economic, and social peripheralization, marginalization, and the rise of the far right. The development of solar energy, we argue, is merely the latest iteration of an industrial growth model that is rooted in a similar modernist mode of development. Based on original mixed methods field research in eastern Germany, it argues that many of the same inequalities that characterize fossil fuels and “gray” (de)industrialization—undemocratic and unsustainable industrial processes, the concentration of corporate power and profits, and externalized waste and pollution—are replicated by solar energy. What is distinct is the fact that such contemporary “green” manufacturing processes appear to negatively affect a wider and more dispersed range of spatial locations, also denying these locales the benefits of accumulation, production, and consumption. This unevenness reflects the reconfiguration of global supply chains over the past thirty years and the nature of green production processes that depend on a wider range of inputs that invariably produce localized sacrifice zones. We offer a spatial justice framework for solar energy, zooming in at the manufacturing stage, to explore the multiple sacrifice zones at the different stages of solar energy. Finally, we highlight the politics of resignation that is the product and foundation of capitalist realism that serves to dispossess communities around solar energy manufacturing sites in eastern Germany and might feed into the rise of the populist far right. The article contributes to the emerging critical literature that analyzes the dark side of renewable energy and, in doing so, reveals the social and ecological costs of energy transitions that continue to be underresearched yet deserve heightened attention.

Closed Form Option Pricing for Stocks with Fixed Dividends

This article discusses a simple, fast and accurate closed-form solution for European options and forwards on a stock with discrete, fixed-amount dividends, and robust w.r.t. a wide range of inputs. While many various precise expansion approaches exist, we are looking for a simple, easy to implement and fast method that works across a wide range of inputs. The option with dividends can be transformed into an average option that can be solved using well-known methods for average options, such as Curran. We find that this is the best compromise between accuracy, simplicity and speed for a wide range of practical applications.

A High Conversion Gain Envelope Detector with Wide Input Range for Simultaneous Wireless Information and Power Transfer System

Wireless sensors networks (WSN) have been gradually facilitating the pervasive connectivity of wireless sensor nodes. A greater number of wireless sensors have been used in different aspects of our life. However, limited device battery life restricts the applications of large-scale WSN. This paper presents a batteryless envelope detector with radio frequency energy harvesting (RFEH) for wireless sensor nodes, which enables simultaneous wireless information and power transfer (SWIPT). The envelope detector is designed for small modulation index AM signals with large amplitude variations. Therefore, the envelope detector is supposed to have wide input range while achieving a high conversion gain. We proposed an adaptive biasing technique in order to extend the input range of envelope detector. The input differential pair is adaptively biased through a feedback loop to overcome the variation of bias point when the amplitude of input signal changes. The cross coupled rectifier and DC-DC boost converter with maximum power point tracking (MPPT) are presented against power conversion efficiency (PCE) degradation of RF rectifier with the input power varying. The adaptive biased envelope detector is theoretically analyzed by square law MOSFET model. Designed with 0.18 μm complementary-metal-oxide-semiconductor (CMOS) standard process, the power consumption of proposed envelope detector is 9 μW. Simulated with a 915 MHz AM input signal with 2 Mbps data rate and 0.05 modulation index, the proposed envelope detector achieves 20.37 dB maximum conversion gain when the amplitude of input signal is 0.5 V, and the PCE of energy harvesting circuits achieves 55.2% when input power is –12.5 dBm.