Showing papers on "Precision rectifier published in 2010"

Controller for a synchronous rectifier switch

Abstract: A controller for a power converter and method of operating the same employable with a bridge rectifier having first and second synchronous rectifier switches. In one embodiment, the controller includes an amplifier configured to enable a turn-on delay for the first synchronous rectifier switch. The controller also includes a discharge switch having first and second switched terminals coupled to gate and source terminals, respectively, of the first synchronous rectifier switch and configured to discharge a gate-to-source capacitance of the first synchronous rectifier switch to enable a turn off thereof.

Control of Three-Phase Boost-Type PWM Rectifier in Stationary Frame Under Unbalanced Input Voltage

Abstract: In the last decade, many methods for control of three-phase boost-type pulsewidth modulation (PWM) rectifier under unbalanced input voltage conditions have been studied and presented. These methods use the sequential components of input voltages, pole voltages, and input currents of the rectifier to analyze and control the instantaneous powers, of which dual (positive-sequence and negative-sequence rotating) frame control is the most common structure. Anyway, this paper analyzes the instantaneous powers of the PWM rectifier in two-phase stationary frame. Based on this analysis, the input-power-control, input-output-power-control, and output-power-control methods for PWM rectifier under unbalanced voltage conditions are proposed in single stationary frame. Compared with the existing methods, simplicity may be the major advantage of the method in this paper. Rotating transformation and phase detection of the input voltages are both eliminated. Moreover, sequential component extraction of the control variables is also not necessary, leading to much reduced time delay to the control system. Experimental results on a 9-kVA PWM rectifier show validity and effectiveness of the proposed methods.

Zero-Voltage-Transition PWM Converters With Synchronous Rectifier

Abstract: In this paper, a family of zero-voltage-transition (ZVT) pulsewidth-modulated converters with synchronous rectifier (SR) is introduced. The SR decreases the conduction losses, while it increases the achieved soft switching range. In this family of converters, zero-voltage-switching (ZVS) condition is attained for the main and rectifier switches. Also, zero-current switching is achieved for the auxiliary switch. In addition, the applied ZVS technique can eliminate the reverse recovery losses of the rectifier switch body diode. The ZVT buck converter with SR is analyzed, and the presented experimental results confirm the theoretical analysis.

Power-supply unit, hard-disk drive, and switching method of the power-supply unit

Abstract: A power-supply unit including a transformer, a full bridge circuit having four arm switches on a primary side of the transformer, a rectifier and smoothing circuit including two synchronous rectifier switches on a secondary side of the transformer, a choke coil, and a capacitor, an output terminal in the rectifier and smoothing circuit, a control circuit controlling ON/OFF of the four arm switches of the full bridge circuit and the two synchronous rectifier switches of the rectifier and smoothing circuit, a resonant inductor including a leakage inductor component and a parasitic inductor component on the primary side of the transformer, and a resonant capacitor, and in which the control circuit includes a timing variable unit which varies switching timings of the two synchronous rectifier switches of the rectifier and smoothing circuit based on an output current flowing in the output terminal provided in the rectifier and smoothing circuit

A Novel Current-Mode Full-Wave Rectifier Based on One CDTA and Two Diodes

Abstract: Precision rectifiers are important building blocks for analog signal processing. The traditional approach based on diodes and operational amplifiers (OpAmps) exhibits undesirable effects caused by limited OpAmp slew rate and diode commutations. In the paper, a full-wave rectifier based on one CDTA and two Schottky diodes is presented. The PSpice simulation results are included.

Near zero turn-on voltage high-efficiency UHF RFID rectifier in silicon-on-sapphire CMOS

Abstract: A UHF RFID rectifier which turns on at near zero input voltage is demonstrated. The rectifier is fabricated in 0.25-µm silicon-on-sapphire (SOS) CMOS technology using intrinsic, near zero threshold devices. A novel improved cross-coupled bridge topology is used to minimize the leakage incurred through the use of intrinsic devices while maintaining their low power turn on characteristics. The fabricated rectifier demonstrates a peak power conversion efficiency (PCE) of 71.5% at 915MHz with a RF input of −4 dBm and a 30 kΩ load. More importantly, a PCE ≫ 30% was measured for all RF input powers between −28 and −4 dBm demonstrating state-of-the-art efficiency across a wide range of input powers.

Design methodology and comparison of rectifiers for UHF-band RFIDs

Abstract: Rectifiers are important energy converters and henceforth crucial building blocks for RFID applications. In the first half of the work, we have presented a design methodology for matching the rectifier input impedance with the antenna to maximize the rectifier power conversion efficiency. The proposed design approach uses the fundamental transconductance (Gm(1)) analysis to estimate the rectifier input impedance. In the second half, a comparison between various possible single-stage rectifier topologies implemented in a CMOS 0.18 µm technology operating at UHF-band is presented. Using voltage conversion efficiency as the FOM, the optimum rectifier topology for RFID application is determined.

A high-efficiency CMOS rectifier for low-power RFID tags

Abstract: In this paper, a high-efficiency highly sensitive CMOS rectifier for radio-frequency identification (RFID) tags is presented. Although the minimum RF input signal amplitude for which the rectifier operates properly is lower than the standard threshold voltage of the MOS transistors, the design uses only standard-threshold-voltage (standard-V th ) devices. Furthermore, two rectifier biasing schemes are proposed. The first biasing scheme is intended for semi-passive RFID tags and allows the tag rectifier to adjust the input power level at which the rectifier's maximum power efficiency is achieved, i.e., the rectifier circuit can be tuned to achieve its maximum power efficiency at any given input power. The second biasing scheme is for self-sufficient rectifiers used in passive tags and does not require any auxiliary power source. The rectifier is designed and laid out in a standard 0.13-µm CMOS process and its performance is confirmed through post-layout simulations.

A High-Performance CMOS Feedforward AGC Circuit for a WLAN Receiver

Abstract: This paper presents a fast-settling compact feedforward automatic-gain-control (AGC) circuit suitable for use in wireless local-area network receivers with orthogonal frequency-division multiplexing (OFDM). The use of these signals introduces stringent settling-time constraints which limit the use of traditional closed-loop feedback amplifiers. Furthermore, the amplitude detection of OFDM signals cannot be performed by a typical peak detector (PD) due to their high peak-to-average power ratio; as a consequence, a novel fast-settling PD is employed to solve this task. The AGC has been implemented in a low-cost 0.35-μm CMOS technology. Supplied at 1.8 V, it operates with a power consumption of 2.4 mW at frequencies as high as 100 MHz, while its gain ranges from 0 to 22 dB in 2-dB steps through a 5-b word. The settling time of the circuit is below 2.4 μs (three symbols).

Self-powered piezoelectric energy harvesting device using velocity control synchronized switching technique

Abstract: With the rapid development of low power consumption electronics, wireless sensor networks (WSN) are highly investigated and used to improve our life quality. Using piezoelectric materials to transfer the mechanical energy into electrical energy for batteries of WSN in order to extend the life time is the focus in many researches in the recent years. It is important and efficient to improve the energy harvesting by designing an optimal interface between piezoelectric device and the load. In this paper, a self-powered piezoelectric energy harvesting device is proposed based on the velocity control synchronized switching technique (V-SSHI). Comparing to diode full bridge rectifier standard technique, the synchronized switching harvesting on inductor (SSHI) technique can highly improve harvesting efficiency. However, in real applications when the energy harvesting device is associated with WSN, the SSHI technique needs to be implemented and requires being self-powered. The conventional technique to implement the self-powered SSHI is to use bipolar transistor as voltage peak detector. In this paper, a new self-powered device is proposed, using velocity control to switch the MOSFET more accurately than in the conventional technique. The concept of design and theoretical analysis is presented in detail. Experimental results are examined and show better performance.

Single-Stage Electronic Ballast Using Class-DE Low- ${d} \upsilon/{d}t$ Current-Source-Driven Rectifier for Power-Factor Correction

Abstract: A single-stage high-power-factor electronic ballast with a Class-DE low-dv/dt rectifier as a power-factor corrector is proposed in this paper. The power-factor corrector is achieved by using a bridge rectifier that acts as the Class-DE low-dv/dt rectifier. The Class-DE low-dv/dt rectifier is driven by a high-frequency current source, which is obtained from the square-wave output voltage of the Class-D parallel resonant inverter through an LC -series circuit. By using this topology, the conduction angle of the bridge rectifier diode current is increased, and a low line-current harmonic is obtained. A prototype ballast is implemented to drive a 36-W fluorescent lamp. The switching frequency is fixed at about 84 kHz. Experimental results verify the theoretical analysis. The designed electronic ballast has a power factor of 0.99, a total harmonic distortion of 1.3%, a lamp current crest factor of 1.42, and 90% efficiency at full power.

A 2.45-GHz low cost and efficient rectenna

Abstract: This paper reports a novel rectifying antenna (rectenna) based on modified bridge rectifier with four Schottky diodes. The 2.45-GHz microwave rectifier has been developed and optimized using a global simulation technique which associates electromagnetic and circuit approaches in order to accurately predict the rectifier performances. The presented device doesn't need neither input HF filter nor bypass capacitor. This makes the structure more compact and low cost. A 2.45GHz linearly polarized patch antenna has been designed and associated to the microwave rectifier to obtain the full rectenna. The rectifier achieves an RF-to-dc conversion efficiency of 61% at 10 mW input power. When the power density is 0.15 mW/cm², the full rectenna circuit shows an efficiency of 52% over an optimal resistive load of 1050Ω.

High frequency and high precision CMOS full-wave rectifier

Abstract: This paper presents a new high frequency and high precision full-wave rectifier, which is very suitable for CMOS technology implementation. The system comprises a voltage to current converter, precision full-wave rectifiers and a current to voltage converter. An input voltage signal is converted into two symmetrical current signals by using a dual-output operational transconductance amplifier. Two current signals will be rectified by using junction diodes and convert into output voltage by using a grounded MOS resistor. Simulated rectifier results based on a 0.5μm CMOS technology demonstrates very high operating frequency and very precise rectification.

A Novel Current-Fed Boost Converter With Ripple Reduction for High-Voltage Conversion Applications

Abstract: Employing a new rectifier circuit, i.e., a novel current-fed boost converter with ripple reduction, is proposed in this paper. It features high conversion ratio with smaller transformer turn ratio, recovery of transformer secondary leakage energy, low voltage stress on the rectifier diodes, and lower input- and output-current ripples with minimum component count. Therefore, high efficiency and power density can be achieved under high-frequency operation. Moreover, the new rectifier circuit can be applied to all current-fed power topologies for high-voltage conversion applications, such as fuel-cell-powered systems. The operating principle, theoretical analysis, and design considerations are presented. To demonstrate its feasibility, a 150-kHz, 16-22-V-input, and 200-V/400-W-output converter is implemented and tested.

Bridgeless buck PFC rectifier

Abstract: A new bridgeless buck PFC rectifier that substantially improves efficiency at low line of the universal line range is introduced. By eliminating input bridge diodes, the proposed rectifier's efficiency is further improved. Moreover, the rectifier doubles its output voltage, which extends useable energy of the bulk capacitor after a drop-out of the line voltage. The operation and performance of the proposed circuit was verified on a 700-W, universal-line experimental prototype operating at 65 kHz. The measured efficiencies at 50% load from 115-V and 230-V line are both close to 96.4%. The efficiency difference between low line and high line is less than 0.5% at full load. A second-stage half-bridge converter was also included to show that the combined power stages easily meet Climate Saver Computing Initiative Gold Standard.

Minimal configuration precision full-wave rectifier using current and voltage conveyors

Abstract: In this paper, new minimal configuration precision full-wave rectifier is presented. The structure employs one current and one voltage conveyor and only two diodes. It enables to process both low-voltage and low-current signals. Compared to the op amp based circuit, the proposed circuit is able to rectify signals up to 500kHz and beyond with no or small distortion. Experimental measurements are performed that show the feasibility of the new precision full-wave rectifier.

An ultra-low-voltage active rectifier for energy harvesting applications

Abstract: This paper presents an ultra-low-voltage active rectifier for micro energy harvesting. A two stage concept is used including a first passive stage and an active diode as second stage. A bulk-input comparator design is used which is well suited for low voltage applications. The power consumption is 200 nW and the minimum operation voltage is 350 mV using a 0.35 µm low V Th CMOS technology. The voltage drop over the rectifier is some tens of millivolt which results in voltage and power efficiencies of over 90 %. Input voltages with frequencies in the range of mHz to low kHz can be rectified.

High Speed Rectifier Circuit

Abstract: Provided is a rectifier circuit that includes a depletion mode semiconductor having an output connected to a rectified signal output node of the rectifier circuit and a hot carrier semiconductor diode having a cathode connected to a source node of the depletion mode semiconductor and an anode connected to a gate node of the depletion mode semiconductor. The rectifier may include an alternating current (AC) input node that is connected to the anode of the hot carrier semiconductor diode and the gate node of the depletion mode semiconductor and that is configured to receive an AC input signal.

A Novel Versatile Precision Full-Wave Rectifier

Abstract: In this paper, we have proposed and realized a novel precision full-wave rectifier using an all-pass filter as a 90° phase shifter. The circuit gives a dc output voltage that is almost the same as the peak input voltage over a frequency range of 50 Hz-1 MHz with a very low ripple voltage and low harmonic distortion. Oscilloscope traces of the rectified waveform for the proposed circuit show a ripple voltage of 12 mV obtained with an input voltage of amplitude 1 V and frequency 100 kHz.

EMI filter design for high switching frequency three-phase/level PWM rectifier systems

Abstract: The actual attenuation characteristic of EMI filters in practice often differs from theoretical predictions and minor changes could result in a significant performance improvement. Whereas the performance of the differential-mode (DM) filter stage usually can be well predicted, the common-mode (CM) behavior is more difficult to handle. This is especially true for three-phase PWM rectifier systems, which show a large high-frequency CM voltage at the rectifier output. In this work the possible CM noise current paths of a three-phase/level PWM rectifier are analyzed where parasitic capacitances to the heat sink and to earth are considered. Additionally, a concept to significantly reduce CM emissions is discussed in detail. Based on the proposed models an EMI filter design for a system with 1 MHz switching frequency is shown. Experimental verification of the designed EMI filter is presented by impedance and conducted emission (CE) measurements taken from a 10 kW hardware prototype. Several practical aspects of filter realization like component arrangement, shielding layers, magnetic coupling etc. are discussed and verified by measurements.

High linear fast peak detector

Abstract: A high linear fast peak detector having a variable bias current and/or a variable bias voltage is described. In an exemplary design, the peak detector includes a transistor, a variable current source, a capacitor, and a feedback circuit. The transistor receives the input signal and provides a source current. The variable current source receives the input signal, provides high bias current when the input signal is low, and provides low bias current when the input signal is high. The capacitor is charged by the source current when the input signal is high and is discharged by the high bias current when the input signal is low. The feedback circuit receives a detected signal from the capacitor and provides higher bias voltage for the transistor when the input signal is high, which results in higher source current from the transistor.

Power converter having synchronous rectifier and control method of synchronous rectifier

Abstract: Disclosed is a power converter including a switching circuit; a transformer having a primary winding connected to the switching circuit and a secondary winding; a main control circuit connected to the switching circuit for outputting a main control signal to manipulate the switching circuit; at least one synchronous rectifier connected to the secondary winding; at least one current transformer connected to the synchronous rectifier for outputting a detecting signal according to a current flowing through the synchronous rectifier; and at least one synchronous rectification control circuit connected to a control terminal of the synchronous rectifier, the current transformer, and a control terminal of the switching circuit for receiving the detecting signal and the main control signal for manipulating the synchronous rectifier. In case that the main control circuit manipulates the switching circuit to turn on, the synchronous rectification control circuit manipulates the synchronous rectifier to turn on, and thereby allowing the synchronous rectification control circuit to manipulate the synchronous rectifier to turn off according to the detecting signal.

Electromagnetic field detection systems and methods

Abstract: Detectors and other apparatus for determining the presence of electromagnetic events are disclosed. One such system includes an electromagnetically shielded enclosure and a detector configured to detect an electromagnetic field event occurring in the proximity of the enclosure. The detector includes an antenna and a circuit electrically connected to the antenna. The circuit includes electronics communicatively connected to the antenna via a direct current isolation circuit, and an equalizer compensating for the differentiating frequency response of the antenna. The circuit also includes a logarithmic amplifier electrically connected to the equalizer and configured to generate a range of signals based on signals received at the antenna, and a peak detector receiving signals from the logarithmic amplifier and configured to capture a peak value of the signals. An electromagnetic field event is detected at least in part based on the peak signal value.

Semi-active high-efficient CMOS rectifier for wireless power transmission

Abstract: A semi-active high-efficient (SA-HE) CMOS rectifier with reverse leakage control has been developed. It employs a cross-coupled NMOS pair and two leakage control comparators to reduce reverse charge leakage current. In addition, the adaptive body bias control technique is utilized to improve the reliability of the rectifier. The SA-HE rectifier has been fabricated in a 0.18um CMOS technology and shows 15% improvement over conventional rectifiers.

Push–Pull Forward Three-Level Converter With Reduced Rectifier Voltage Stress

Abstract: This paper proposes a push-pull forward three-level (TL) converter, which is suitable for low and wide-range input-voltage applications, such as fuel cell and solar cell. Half of the switches sustain half of the input voltage, and the others sustain one and one-half input voltage. The input ripple current and output filter inductor ripple current can be reduced with TL waveform of the secondary rectified voltage. However, the voltage stress of a rectifier diode is high with the conventional TL control strategy in a high output-voltage situation, considering voltage spike across the rectifier diode caused by the leakage inductance. When 1/2 level of the secondary rectified voltage shows first and one level of that appears later, the voltage stress of the rectifier diode can be reduced by paralleling with a small external capacitor. The operating principle, control strategy, and design guidelines and example are analyzed. Finally, experimental results verify the theoretical analysis.

AC/DC power converter with active rectification and input current shaping

Abstract: An AC/DC power converter has an AC input and a DC output, with an input rectifier circuit coupled to the AC input. The input rectifier circuit includes a passive half-bridge rectifier circuit functional to provide passive rectification of an AC input power sign and at least one current shaper circuit. The current shaper circuit includes an input inductor coupled between the AC input and a switch node in the input active rectifier circuit. The input current shaper circuit is functional to shape an AC input current signal associated with an AC input power signal to a substantially sinusoidal current signal. A bulk capacitor circuit is coupled to the input active rectifier circuit. A DC/AC converter circuit is coupled to the bulk capacitor circuit. A resonant circuit is coupled to the DC/AC converter circuit and an output rectifier circuit may be coupled between the resonant circuit and the DC output.

Simple controller for single-phase power factor correction rectifier

Abstract: This study proposes a simple low-cost modulating duty cycle analogue controller to reduce line frequency harmonics for high power factor boost rectifier. The proposed method eliminates the need for current sensing, and simultaneously offers the performance results comparable to those of continuous conduction mode (CCM). This scheme also maintains the simplicity comparable to that of discontinuous conduction mode (DCM). Only the output voltage and the rectified input voltage are monitored to vary the duty cycle of the boost switch within a line cycle so that the third-order harmonic, which is the lowest order harmonic of the input current, is reduced. As a result, the total harmonic distortion (THD) of the line current and thus the input power factor is improved. Moreover, the rectifier shows a good transient performance where the converter's output voltage overshoots during input voltage/load transients is reduced. The proposed method is developed for constant switching frequency boost rectifier. Simulation and experimental results are presented to verify the effectiveness of the proposed control method.

A low voltage CMOS rectifier for wirelessly powered devices

Abstract: This paper presents a low voltage CMOS full-wave rectifier for wirelessly powered devices. By using a simple comparator-controlled switch, the lowest input voltage amplitude can be reduced to 0.7V when using a standard CMOS 0.18μm process. With only one comparator, the proposed design dramatically reduces the production cost. In combination with unbalanced transistor scale, the proposed rectifier can achieve a maximum peak voltage conversion efficiency of more than 93% and power efficiency near to 87%.

Charge pump stage of radio-frequency identification transponder

Abstract: A charge pump stage (400) of an RFID transponder includes an RF node (402), a capacitor bank (404) , a plurality of current-biased rectifier stages (406,408,410), a DC bus, a programmable current source (412) and a control circuit (414). The RF node (402) provides an RF signal. The capacitor bank (404) has a selectable capacitance and is electrically coupled to the RF node (402). The plurality of current-biased rectifier stages (406,408,410) receives the RF signal from the RF node (402). The plurality of current-biased rectifier stages (406,408,410) provides a DC output. The DC bus (418) receives the DC output from the plurality of rectifier stages (406,408,410) and provides a supply voltage. The programmable current source (412) provides a plurality of current bias signals for each of the plurality of current-biased rectifier stages (406,408,410). The control circuit (414) is in electrical communication with the capacitor bank (404) and the programmable current source (412). The control circuit (414) selects the selectable capacitance of the capacitor bank (404) and programs the current source (412).