Current‐mode dual‐output ICCII‐based tunable universal biquadratic filter with low‐input and high‐output impedances

A new tunable current‐mode (CM) biquadratic filter with three inputs and three outputs using three dual‐output inverting second‐generation current conveyors, three grounded resistors and two grounded capacitors is proposed. The proposed circuit exhibits low‐input impedance and high‐output impedance which is important for easy cascading in the CM operations. It can realize lowpass, bandpass, highpass, bandreject and allpass biquadratic filtering responses from the same topology. The circuit permits orthogonal controllability of the quality factor Q and resonance angular frequency ω_o, and no component matching conditions or inverting‐type input current signals are imposed. All the passive and active sensitivities are low. Hspice simulation results are based on using TSMC 0.18 µm 1P6M process complementary metal oxide semiconductor technology and supply voltages ±0.9 V to verify the theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

All‐pass sections with rich cascadability and IC realization suitability

In this paper, two new circuit configurations for realizing voltage‐mode (VM) all‐pass sections (APSs) are presented. The proposed circuits employ only two differential voltage current conveyors (DVCCs) and are cascadable with other VM circuits due to their high‐input and low‐output impedances. The first configuration uses a grounded resistor and a grounded capacitor without requiring matching constraints, whereas the second employs two grounded resistors and a grounded capacitor with a single matching condition. While the first configuration can realize only one all‐pass response, the second can provide inverting and non‐inverting all‐pass responses with selection of appropriate input port. Adding two grounded resistors to the proposed filters, variable gain APSs can also be obtained. As applications, two quadrature oscillators, each of which using one of the proposed all‐pass circuits, one grounded resistor and one grounded capacitor are presented. SPICE simulation results are included to verify the theory. Copyright © 2010 John Wiley & Sons, Ltd.     

Voltage mode and current mode Tow Thomas bi‐quadratic filters using inverting CCII

A voltage mode Tow Thomas bi‐quadratic filter using the inverting second‐generation current conveyor (ICCII) is given. The filter has high input impedance, employs two grounded capacitors, and has independent control on Q, independent control on the band‐pass and low‐pass response gain. Three alternative current mode filters are generated from the voltage mode circuit. The three circuits have zero input impedance, employ grounded capacitors and have independent control on Q. Two of the circuits have also all resistors grounded and the other uses only ICCII?and has only one floating resistor. Copyright © 2007 John Wiley & Sons, Ltd.     

Low‐voltage high‐performance current mirrors: Application to linear voltage‐to‐current converter

Current mirror is one of the basic building blocks of analog VLSI systems. For high‐performance analog circuit applications, the accuracy and bandwidth are the most important parameters to determine the performance of the current mirror. This paper presents an efficient implementation of a CMOS current mirror suitable for low‐voltage applications. This circuit combines a shunt input feedback, a regulated cascade output and a differential amplifier to achieve low input resistance, high accuracy and high output resistance. A comparison of several architectures of this scheme based on different architectures of the amplifier is presented. The comparison includes: input impedance, output impedance, accuracy, frequency response and settling time response. These circuits are validated with simulation in 0.18µm CMOS TSMC of MOSIS. In this paper, a linear voltage to current converter, based on the adapted current mirror, is proposed. Its static and dynamic behaviour is presented and validated with the same technology. Copyright © 2009 John Wiley & Sons, Ltd.     

A three‐phase constant‐current source using an immittance converter

The term immittance converter refers to an impedance–admittance converter. The immittance converter has an input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant‐voltage source into a constant‐current source and a constant‐current source into a constant‐voltage source. It is well known that the quarter wavelength transmission line shows immittance conversion characteristics. However, it has a very long line length for the switching frequency, and is not suitable for power electronics applications. We thus proposed immittance converters that consist of lumped elements L, C and show improved immittance conversion characteristics at a resonant frequency. A three‐phase constant‐current source is proposed in this paper. It is possible to realize this by a simple circuit using an immittance converter. In this paper, circuit operation, characteristic equations, and results of simulation are described. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 47–54, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20078     

A novel three‐phase converter using a three‐phase series chopper

This paper proposes a novel three‐phase converter using a three‐phase series chopper. The proposed circuit is composed of three switching devices, three‐phase diode bridge, input reactors, and LC low‐pass filter. In the conventional circuit, which combines three‐phase diode bridge and boost voltage chopper, to obtain sinusoidal input current the output voltage must be two or three times larger than the maximum input line voltage. However, in the proposed circuit, the input current can be controlled to be sinusoidal also when the output voltage is the same as the maximum input line voltage. This can be achieved because in the proposed circuit the discharging current of the reactors does not flow through the voltage source. The control method of the proposed circuit is as simple as that of the conventional circuit since all three switching devices are simultaneously turned on and off. This paper discusses the theoretical analysis and the design of the proposed circuit. In addition, simulation and experimental results are reported. The proposed circuit has obtained a 93% efficiency, and 99.7% at 1.3kW load as the input power factor. © 2000 Scripta Technica, Electr Eng Jpn, 132(4): 79–88, 2000     

Analytical synthesis of voltage‐mode even/odd‐nth‐order differential difference current conveyor and fully differential current conveyor II‐grounded resistor and capacitor universal filter structures

A complete definition of an odd/even‐nth‐order notch or band‐reject filter transfer function is presented. Based on the differences between the input voltage and (i) an nth‐order high‐pass; (ii) a traditional nth‐order notch; and (iii) an nth‐order all‐pass filtering transfer function, a systematic method has been proposed to derive a universal filter structure that can realize voltage‐mode odd/even‐nth‐order low‐pass, band‐pass, high‐pass, all‐pass and traditional notch filters. The intrinsic capability of voltage‐mode addition and subtraction of the two active elements, differential difference current conveyors and fully differential current conveyors, is used to advantage in the aforementioned synthesis procedure. Based upon the definition of an nth‐order notch or band‐reject filter transfer function proposed in this paper, the aforementioned universal one has been further extended to the newly defined nth‐order band rejection filter. The voltage and current tracking errors of the two active elements are compensated by varying the resistances of the proposed filter. Filtering feasibility, stability, component sensitivities, linear and dynamic ranges, power consumption, and noise are simulated using H‐Spice with 0.35 µm process. Compared to some of the recently reported universal biquads, the new one is shown to enjoy the lowest component sensitivities and the best output accuracy for all‐pass signals. Moreover, Monte Carlo and two‐tone tests for intermodulation linearity simulations are also investigated. Copyright © 2014 John Wiley & Sons, Ltd.     

Universal current‐mode filters and parasitic impedance effects on the filter performances

In this letter, two universal current‐mode (CM) filters for simultaneously realizing low‐pass, band‐pass and high‐pass characteristics are proposed. Both of the presented filters can also realize notch and all‐pass responses with interconnection of the relevant output currents. They employ second‐generation current‐controlled conveyors (CCCIIs) and only grounded capacitors. They also have low active and passive element sensitivities along with electronically adjustable angular resonance frequency (ω₀) and quality factor (Q). Based on the first developed filter, the parasitic impedance effects of the conveyors on the filter performances are investigated in detail. Simulation results using SPICE simulation program are included to verify the theory. Copyright © 2007 John Wiley & Sons, Ltd.     

High input impedance voltage‐mode first‐order all‐pass sections

This paper proposes six new first‐order voltage‐mode all‐pass sections (VM‐APSs) based on three general topologies. Each circuit uses two differential voltage current conveyors and three grounded passive components. All the circuits possess high input impedance and easy control of pole frequency either by a simple matching of resistors (two equal‐valued resistors) for the three canonical circuits or by a single resistor for three non‐canonical circuits. PSPICE simulation results using real device 0.5µ CMOS parameters are given to validate the proposed circuits. Copyright © 2007 John Wiley & Sons, Ltd.     

Single‐stage single‐switch PFC converter for wide‐input extreme step‐down voltage applications

This paper presents a new single‐stage single‐switch high power factor correction AC/DC converter suitable for low‐power applications (< 150 W) with a universal input voltage range (90–265 V_rms). The proposed topology integrates a buck–boost input current shaper followed by a buck and a buck–boost converter, respectively. As a result, the proposed converter can operate with larger duty cycles compared with the existing single‐stage single‐switch topologies, hence, making them suitable for extreme step‐down voltage conversion applications. Several desirable features are gained when the three integrated converter cells operate in discontinuous conduction mode. These features include low semiconductor voltage stress, zero‐current switch at turn‐on, and simple control with a fast well‐regulated output voltage. A detailed circuit analysis is performed to derive the design equations. The theoretical analysis and effectiveness of the proposed approach are confirmed by experimental results obtained from a 100‐W/24‐V_dc laboratory prototype. Copyright © 2011 John Wiley & Sons, Ltd.     

Series resonant ZCS‐PFM DC‐DC power converter with high‐frequency high‐voltage transformer link for high‐power magnetron drive

This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126     

CMOS high‐precision loser‐take‐all circuit

This paper presents a new current‐mode CMOS loser‐take‐all circuit. The proposed circuit consists of a basic cell that allows implementation of a multi‐input configuration by repeating the cell for each additional input. A high‐speed feedback structure is employed to determine the minimum current among the applied inputs. The significant feature of the circuit is its high accuracy and high‐speed operation. Additionally, the input dynamic range of the circuit can be efficiently controlled via the biasing current. HSPICE simulation results are presented to verify the performance of the circuit, where under a supply voltage of 2.5 V, bias current of 100 µA, and frequency of 10 MHz, the input dynamic range increases within 0–100 µA and the corresponding error remains as low as 0.4%. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Soft‐switching converter with low circulating current and wide range of ZVS turn‐on

In this paper, a new hybrid dc–dc converter with low circulating current within the freewheeling interval, wide range of zero‐voltage switching and reduced output current ripple is presented. The proposed hybrid circuit includes two three‐level pulse‐width modulation converters and a series resonant converter with the shard lagging‐leg switches. Series resonant converter is operated at fixed switching frequency (close to series resonant frequency) to extend the zero‐voltage switching range of lagging‐leg switches. The output of series resonant converter is connected to the secondary sides of three‐level converters to produce a positive rectified voltage instead of zero voltage. Hence, the output inductances can be reduced. The reflected positive voltage is used to decrease the circulating current to zero during the freewheeling interval. Therefore, the circulating current losses in three‐level converters are improved. Finally, experiments are presented for a 1.44 kW prototype circuit converting 800 V input to an output voltage 24 V/60A. Copyright © 2015 John Wiley & Sons, Ltd.     

A single‐stage LED streetlight driver with PFC and digital PWM dimming capability

This paper proposes a single‐stage light‐emitting diode (LED) driver that offers power‐factor correction and digital pulse–width modulation (PWM) dimming capability for streetlight applications. The presented LED streetlight driver integrates an alternating current–direct current (AC–DC) converter with coupled inductors and a half‐bridge‐type LLC DC–DC resonant converter into a single‐stage circuit topology. The sub‐circuit of the AC–DC converter with coupled inductors is designed to be operated in discontinuous‐conduction mode for achieving input‐current shaping. Zero‐voltage switching of two active power switches and zero‐current switching of two output‐rectifier diodes in the presented LED driver decrease the switching losses; thus, the circuit efficiency is increased. A prototype driver for powering a 144‐W‐rated LED streetlight module with input utility‐line voltages ranging from 100 to 120 V is implemented and tested. The proposed streetlight driver features cost‐effectiveness, high circuit efficiency, high power factor, low levels of input‐current harmonics, and a digital PWM dimming capability ranging from 20% to 100% output rated LED power, which is fulfilled by a micro‐controller. Satisfying experimental results, including dimming tests, verify the feasibility of the proposed LED streetlight driver. Copyright © 2016 John Wiley & Sons, Ltd.     

A 0.5 V bulk‐driven voltage follower/DC level shifter and its application in class AB output stage

A simple realization of a 0.5 V bulk‐driven voltage follower/direct current (DC) level shifter designed in a 0.18 µm CMOS technology is presented in the paper. The circuit is characterized by large input and output voltage swings and a DC voltage gain close to unity. The DC voltage shift between input and output terminals can be regulated in a certain interval around zero, by means of biasing current sinks. An application of the proposed voltage follower circuit for realization of a low‐voltage class AB output stage has also been described in the paper. Finally, the operational amplifier exploiting the proposed output stage has been presented and evaluated in detail. Copyright © 2014 John Wiley & Sons, Ltd.     

FDCCII‐based electronically tunable voltage‐mode biquad filter

In this work, a voltage‐mode biquad filter realizing low‐pass, band‐pass and high‐pass characteristics is presented. The proposed filter, which employs two FDCCIIs, two grounded capacitors and two NMOS transistors, provides electronic tunability with the control voltage applied to the gate. NMOS transistors act as linear resistor. Furthermore, the proposed circuit still enjoys realization using a low number of active and passive components, no requirement with the component choice conditions to realize specific filtering functions, high input impedance, and low active and passive sensitivities performance. Simulation results using SPICE program are given to show the performance of the filter and verify the theory. Copyright © 2010 John Wiley & Sons, Ltd.     

Three‐phase immittance converter

The immittance converter has an input impedance that is proportional to the admittance of a load connected across its output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, a constant‐voltage source is converted into a constant‐current source and a constant‐current source into a constant‐voltage source. The immittance converters consisting of only passive elements (inductors L and capacitors C) are suitable for use in the high‐frequency links in power electronics applications. Previously, we proposed several types of immittance converters and some applications to power electronics equipment. In this paper, we propose a new three‐phase immittance converter consisting of three L and C elements each to obtain an alternating current source from a three‐phase voltage source without control. This paper presents a configuration of the new three‐phase immittance converter that operates in either anti‐phase or in‐phase modes between the input voltage and the output voltage, and its voltage–current conversion characteristics and efficiency characteristics. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(1): 52– 58, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10169     

A 0.008‐mm2, 35‐μW, 8.87‐ps‐resolution CMOS time‐to‐digital converter using dual‐slope architecture

This paper presents a high resolution time‐to‐digital converter (TDC) for low‐area applications. To achieve both high resolution and low circuit area, we propose a dual‐slope voltage‐domain TDC, which is composed of a time‐to‐voltage converter (TVC) and an analog‐to‐digital converter (ADC). In the TVC, a current source and a capacitor are used to make the circuit as simple as possible. For the same reason, a single‐slope ADC, which is commonly used for compact area ADC applications, is adapted and optimized. Because the main non‐linearity occurs in the current source of the TVC and the ramp generator of the ADC, a double gain‐boosting current source is applied to overcome the low output impedance of the current source in the sub‐100‐nm CMOS process. The prototype TDC is implemented using a 65‐nm CMOS process, and occupies only 0.008 mm². The measurement result shows a dynamic range with an 8‐bit 8.86‐ps resolution and an integrated non‐linearity of ±1.25 LSB. Copyright © 2016 John Wiley & Sons, Ltd.