Phase Shifter Circuit Research Articles

Analysis and implementation of wide zero‐voltage switching dual full‐bridge converters

A new full-bridge converter is presented to have the advantages of low conduction loss and wide zero-voltage switching (ZVS) range. The proposed converter includes two dc–dc converters connected in parallel to reduce the current stresses of power components. Each dc–dc converter integrates a phase-shift pulse-width modulation full-bridge circuit and an un-regulated half-bridge circuit sharing the lagging-leg switches in order to reduce the switch counts. The un-regulated half-bridge circuit is adopted to extend the ZVS range of the lagging-leg switches to improve the drawback of the narrow ZVS range in conventional full-bridge converter. Two dc–dc converters share the lagging-leg switches so that the switch counts in the proposed converter are less than the switches in conventional parallel full-bridge converters. The resonant capacitors are used on the primary side of full-bridge converters to reduce the primary current to zero at the freewheeling state. The secondary windings of full-bridge and half-bridge converters are connected in series to generate two positive voltage levels at the secondary rectified voltage. Therefore, the output inductor voltage at the freewheeling state is decreased and the output inductor size is reduced. Finally, the effectiveness of the proposed converter is verified by the experiments.

A PWM Phase-Shift Circuit using an RC Delay for Multiple LED Driver ICs

This paper proposes a PWM phase-shift circuit to make that the LED lighting system distributes the channel currents evenly for any number of LED strings by generating evenly phaseshifted PWM signals for multiple LED driver ICs. The evenly distributed channel currents reduce the peak current, the decoupling capacitor size, and EMI noise. The PWM phase-shift circuit makes an arbitrary degree of PWM phase-shift by using a resistor and a capacitor. It measures the RC delay once. It reduces the number of external resistors and capacitors by providing zero and 180 degree phaseshift modes requiring no resistor and capacitor. An LED driver IC with the PWM phase-shift circuit was fabricated with a 0.35 μm BCDMOS process. The PWM phase-shift circuit receives a PWM signal of 50 Hz~20 kHz at f CLK =450 kHz and it generates a 0~360° phase-shifted PWM signal with R=0~1.1 MΩ at C=1 nF and f PWM =1 kHz. The measured phase errors are 1.74~3.94% due to parasitic capacitances.

Reconfigurable Prototyping Microfluidic Platform for DEP Manipulation and Capacitive Sensing.

In this paper, we present a new rapid prototyping platform dedicated to dielectrophoretic microfluidic manipulation and capacitive cell sensing. The proposed platform offers a reconfigurable design including 4 independently programmable output channels to be distributed across 64 electrodes. Although its range of frequency covers up to 3.4 MHz, signal amplitude accuracy ( +/-10%) was demonstrated for frequencies up to 1 MHz and channel-to-channel phase shift setting was stable up to 1.5 MHz. A test of maximum resistive load showed a 10% attenuation of a 12 V peak-to-peak signal with a 22 Ω load. The platform has an advanced capacitive sensor to measure capacitance variation between in-channel electrodes with a sampling frequency up to 5 kH z. Experimental data of capacitive sensor showed a sensitivity of 100 fF. The sensor can be extended to 4 parallel measurements with lower frequency. We also present a new assembly technique for reusable microfluidic chip based on anisotropic adhesive conductive film, epoxy and PDMS. The proposed platform provides a wide range of control signals depending on the type of manipulation as sine, rectangular or square wave. The frequency range is extendible up to 3.4 MHz, in addition to a programmable phase shift circuit with a minimum phase step of 3.6(°) for each signal.

MEMS oscillating squeeze-film pressure sensor with optoelectronic feedback

This work reports on an oscillating pressure sensor that converts pressure into frequency using the squeeze-film effect. A new aspect is the laser Doppler vibrometer (LDV) in the optoelectronic feedback loop that is used to bring the sensor element into sustained mechanical oscillation. A phase shifter and automatic gain control circuit stabilize the oscillation. The frequency stability of the pressure sensor is investigated by measuring its Allan deviation and is compared to the performance of a quartz oscillating pressure sensor. Finally, the pressure resolution of this oscillating sensor is compared to conventional pressure sensors.

Design of a Resonant Reactive Shield With Double Coils and a Phase Shifter for Wireless Charging of Electric Vehicles

In this paper, a novel resonant reactive shield using a double-shield coil and phase-shift circuit is proposed to reduce magnetic field leakage in electric vehicle wireless charging applications. The double-reactive shield with a four-capacitor phase shifter generates a canceling magnetic field, the phase of which is perfectly opposite to that of the incident magnetic field, effectively reducing the leakage magnetic field as a result. The concept and structure, and an equivalent-circuit model analysis of the double-reactive shield are explained and discussed. The shielding effectiveness of the double-reactive shield is compared with that of a conventional reactive shield with a single-shield coil by a simulation and is verified by experiments.

A Single Resistor Tunable Grounded Capacitor Dual-Input Differentiator

A new current feedback amplifier (CFA) based dual-input differentiator (DID) design with grounded capacitor is presented; its time constant (τo) is independently tunable by a single resistor. The proposed circuit yields a true DID function with ideal CFA devices. Analysis with nonideal devices having parasitic capacitance (Cp) shows extremely low but finite phase error (θe); suitable design θe could be minimized significantly. The design is practically active-insensitive relative to port mismatch errors (ε) of the active element. An allpass phase shifter circuit implementation is derived with slight modification of the differentiator. Satisfactory experimental results had been verified on typical wave processing and phase-selective filter design applications.

Low insertion loss, high power handling and good performance 90o phase shifter for X-band radar application

In this paper, a monolithic microwave integrated circuit 90° phase shifter circuit for X band radar application is designed and fabricated using 0.1 μm pseudomorphic high electron mobility transistor technology based on GaAs with f t = 85 GHz. This block is used in passive phase shifters. The structure of 90° used double single port double throw (SPDT) in both input/output. The SPDT used a high yield and good performance switch. The switches have low insertion loss and phase variation. The measurement results of 90° block with ?6 V control voltage indicate that the insertion loss is less than ?1.6 dB and phase shift is 87 ± 3.5° over 8---12 GHz. The 1 dB compression point (P1dB) is more than 25 dBm. The die size is 1 mm2. The measurements show good correlation between simulation and measurement results. So, the result demonstrates the great potential of the proposed block for high performance phased array radar systems.

Research of Drives of Power Amplifiers of Magnetic Levitation Servo Spindle Applied to Micro EDM Based on FPGA

The drives of power amplifiers of magnetic levitation servo spindle applied to micro EDM (Electron discharge machining) based on FPGA (Field programmable gate array) are developed. The drive module that produces the PWM (Pulse width modulation) waves that conform to the requirements of spindle power amplifiers involving three-level half bridge switch power amplifier, three-level full bridge switch power amplifier and motor power amplifier, according to input of action values from magnetic levitation servo spindle controller DSP (Digital signal processor) is designed. Multi-PWM producing algorithm by single timer with multi comparing nodes is proposed. After being applied to control system of magnetic levitation servo spindle, the drives accomplish conversion from DSP action values to PWM waves. The PWMs that drive radial coil current power amplifier have phase difference of 180°. The PWMs that drive axial coil current power amplifier have dead zone time and their wave shapes are complementary. The PWMs that drive the motor power amplifier conform to requirements of power amplifier chip LMD18200. Using FPGA to realize the drive function of spindle power amplifier makes the drive design more flexible, resource distribution of DSP more optimized, the task of algorithms running more centralized, and the drives module gets simpler and more reliable because the phase shift circuit and dead zone circuit are cancelled but the function of phase shift and dead zone is reserved.

Ultrasonic Motor’s H-Bridge Control Circuit Using Phase-Shift PWM Method

Ultrasonic motor is a special kind of actuator for motion control system. Because of the peculiar mechanism of ultrasonic motor, control circuit is needed for the operation of ultrasonic motor. The performance of ultrasonic motor depends on the topology and modulation method of control circuit. A novel type of control circuit for ultrasonic motor, H-bridge control topology using phase-shift PWM method, is proposed in this paper. Two kinds of implementary circuits are designed and analyzed. On the basis of the new designed circuit, the difference of performances between the phase-shift H-bridge circuit and push–pull circuit is analyzed. The experimental results proved that, the performance of the proposed control circuit is good.

Novel Reflectarray Antenna with Quasi-Dipole Unit Cells

This letter presents a novel reflectarray design based on quasi-dipole unit cells. The substrate of the quasi-dipoles is oriented perpendicular to the array surface, giving the advantage of sufficient large area for phase-shifter circuits behind the antenna element. In order to prove the concept at 10 GHz, unit cells are characterized in a waveguide simulator, and far-field measurements of two 8 × 8-element antenna demonstrators are presented. One demonstrator, pointing in a broadside direction, has shown a half-power beamwidth of 15 ° and a sidelobe level of -12 dB in the E-plane. The other demonstrator is pointing toward 20 ° and has shown a sidelobe level of -7 dB with a half-power beamwidth of 20 °.

Closed loop driving and detect circuit of piezoelectric solid-state micro gyroscope

Piezoelectric solid-state micro gyroscope is a novel kind of rotating rate sensor, which is based on the special thickness-shear vibrating mode of a piezoelectric body. Compared with the general vibratory micro gyroscope, it has no evident mass-spring component in its structure, so it has larger stiffness and robust resistance to shake and strike. Therefore, piezoelectric solid-state micro gyroscope can be used in the high-g environment. In this paper, piezoelectric solid-state micro gyroscope working principle is described. The closed loop driving and detect circuit of piezoelectric solid-state micro gyroscope is proposed in order to track the resonance frequency drift, stabilize the driving voltage value and detect the gyroscope output. The closed loop driving circuit (CLDC) mainly contains phase lock loop circuit, automatic gain circuit. Detect circuit mainly contains de-modulator, difference amplifier, Phase shift circuit and low pass filter. Experimental results show that the frequency of CLDC fluctuates within ±15 Hz with the resonance frequency of 357.9 kHz when get its stable status and the fluctuation of reference voltage is within ±7 mv, while the fluctuation of reference voltage in open loop driving circuit is ±23 mv. In the experiment, the sensitivity of the gyroscope with 740 mv/rad/s is observed. The work in the paper provides the theoretical and experimental foundation for realizing for this kind of gyroscope.

중성점을 사용하지 않는 BLDC 전동기 센서리스 제어 기법

Generally, brushless DC motor(BLDCM) driving system uses hall sensors or encoders as the mechanical position or speed sensor. It is necessary to achieve the informations of rotor position for driving trapezoidal type brushless DC motor without any position sensor. In this paper, the commutation signals are obtained without the motor neutral voltage, multistage analog filters, A/D converters, or the complex digital phase shift circuits which are indispensable in the conventional sensorless control algorithms. In the proposed method, in stead of detecting the zero crossing point of the nonexcited motor back electromagnetic force for the average motor terminal to neutral voltage, the commutation signal are extracted directly from the specific average line to line voltage with low-pass filter, adder and comparators circuit. In contrast to conventional methods, the neutral voltage is not need; therefore, the commutation signals are insensitive to the common mode noise. Moreover, the complex phase shift circuit can be eliminated. The effectiveness of the proposed method is verified through simulation results.

An 8-Bit Digitally Controlled Programmable Phase Shifter Circuit for Sinusoidal Signals with 252∘ Phase Control Range

In this paper, the synthesis, design, and implementation of a programmable phase shifter circuit for sinusoidal signals is presented. The proposed circuit, built-up herein with operational amplifiers (OPAMPs), high precision resistors and low voltage switches, consists of a digitally controlled amplitude attenuator in combination with a single-tone orthogonalizer. Experimental results agree with theoretical background: the attained phase range was 252∘ in 256 steps with a median step of 0.9∘. The inaccuracy of the circuit was determined to be of 0.03 %. Contrary to other OPAMP approaches for sinusoidal signals reported in the literature and based on a first-order all-pass filter structure, the approximation suggested in this work is based on a different concept. The achieved results demonstrate the functionality of the system for the case of a sinusoidal signal with frequency of 1 kHz. Notwithstanding, the proposed architecture can be extended to operate at higher frequencies by using different building blocks with larger bandwidth. Furthermore, it can be extended as well to work out with other periodic input waveforms, like triangular shapes or square waves, with the use of an appropriate orthogonalizer.

Design and Implementation of Ultrasonic Velocity Measuring Module Based on Phase-Locked Loop

Due to the important relationship between ultrasonic velocity and some properties of sample, the measurement of velocity of ultrasound is widely needed in various fields. In this paper, based on phase-locked loop technique, a new hybrid circuit is designed for ultrasonic velocity measurement and named as UV-PLL. In order to improve the stability of phase and achieve the ability of fast locking, an auxiliary capturing circuit, which consists of phase shift circuit and capturing circuit, is designed and implemented in this module. Additionally, two methods for estimating the propagation delay is compared and described in detail. The UV-PLL module is validated through the ultrasonic velocity measurement in distilled water at different temperatures. Experimental results show that the maximum relative deviation of velocity measurement is less than 0.15% and the loop can be quickly locked, indicating that this module can meet the requirements of online measurement and can be widely applied. Index Terms—ultrasound, velocity, phase-locked loop (PLL), auxiliary capturing circuit, amplitude I. INTRODUCTION Due to its advantages of non-destruction, rapidity, accuracy and cheapness, ultrasonic testing has become a hotspot in the industrial inspection field. During the process of testing, a lot of interesting properties of sample are related to the ultrasonic velocity. Therefore, the ultrasonic velocity in specific sample is one of the most important parameters and how to accurately measure this parameter becomes the key problem in the whole inspection system (1, 2). Usually, the methods for acoustic velocity measurement can be classified into two categories. One is to acquire the velocity through

OPTIMUM DESIGN OF MODIFIED SCHIFFMAN MULTI-SECTION WIDE BAND DIFFERENTIAL PHASE SHIFTER WITH IMPEDANCE MATCHING

In this paper, a new circuit conflguration composed of two main and reference paths is proposed for the modifled multi- section Schifiman phase shifter, which improves its bandwidth. The method of least squares (MLS) is developed for its design, based on a circuit model including dispersion relations and dissipation efiects. The difierential phase shift and re∞ection coe-cients from the input ports are obtained by conversions among the impedance, admittance, ABCD and scattering matrices of the circuit model. Then, an error function is constructed, whose minimization is performed by the combination of genetic algorithm and conjugate gradient method, which gives the optimum values of the physical dimensions of the metallic strips. The impedance matching function of the proposed phase shifter circuit makes it a dual action device, leading to some circuit miniaturization. Three phase shifter circuits with single, double and quadruple sections are designed and one prototype model is fabricated and measured. The MLS, full-wave simulation softwares and measurement results agree very well, which validate the proposed circuit conflguration and MLS design procedure. The multi-section phase shifters have actually increased the frequency bandwidth.

Technical procedures to select basic parameters of a fluxgate magnetometer

In fluxgate magnetometers, the external magnetic field is generally measured from the second harmonic induced voltage in the pick-up coil. Thus, toimprove the performance of a fluxgate magnetometer design, careful considerations should focus on some operational parameters and how to calibrate them to attainan optimal performance with a minimum intrinsic noise at the output. Basically, two main factors are considered: i) the output dependence on variations of the evenharmonics amplitudes with the excitation current; and ii) adjustments for a perfect timely match between the core saturation and the time-width of the sampling. Thebest sensitivity of the magnetometer is obtained in a portion of the hysteresis curve where the 2nd harmonic component predominates. Since this region depends on theamplitude of the excitation, it becomes necessary to calibrate the excitation amplitude in order to get the highest 2nd harmonic amplitude in the pick-up coil. When theamplitude of the excitation current is modified, the amplitude of the even harmonics also changes, and consequently the magnetometer will operate below its optimalsensitivity, depending on how much the current has changed. Similar result is observed when the core is built with a different inductance (different number of wraps)which requires operational tests to be carried out to verify the level of the core saturation by adjusting the amplitude and the frequency to get the best performancefrom the magnetometer. Changes in the amplitudes of the excitation current generally occur with changes in the excitation current waveform, affecting the timing ofthe core saturation. To avoid bad synchronization between the excitation current and the sampling, the phase shift circuit is locked with the excitation current circuitin order to work together and variations on the excitation current phase is automatically corrected in the sampling circuit. In summary, finding the moment whenthe 2nd harmonic has its greatest value, adjusting the time-width of the synchronous detector and avoiding phase’s shifts between excitation and detection circuitscan produce a magnetometer performing at its lowest noise output.

A 45 nm CMOS miniature phase shifter with constant amplitude response

We present analysis, optimization, design and characterization of an integrated passive analog phase shifter at 24GHz in a commercially available 45nm RF-CMOS process. The design is based on a well-known RC bridge topology, which was optimized for maximum phase shift and minimal amplitude response variation versus phase and frequency. Phase is controlled by varying DC voltage on a varactor, resulting in 60° maximum phase shift with 0.1dB amplitude variation at 24GHz. The size of the phase shifter circuit excluding pads and input/output buffers is 40×50μm2.

Circuit Design for Alternating Current Field Measurement Make Use of Lock-in Amplifier

In ACFM, the measured signal is very weak and always inevitably includes the noises and the unwanted signal. Make use of lock-in amplifier technology to have designed a disturbance magnetic field testing circuit which includes eliminating 2.5 volt DC circuit, amplifying and filtering circuit, phase-shifting circuit and switching voltage multiplier. This circuits designed can performe the measurement and do-nosing for weak magnetic signal of ACFM. The experiment indicated that make use of lock-in amplifier technology to design and optimize ACFM detection circuit is an effective method

AVERAGE CURRENT CONTROL FOR AIRCRAFT APPLICATIONS

Five, single-phase H-bridge converters are used to interface variablespeed,permanent magnet generator into a common DC bus. To drawhigh quality current from the generator and provide constant DCvoltage, a modified implementation of the average current controltechnique is proposed. A phase shift circuit was added to the averagecurrent control to allow system operation at different load and speedconditions. The proposed technique has a significantly fast dynamicperformance. The analysis was validated using rigorous simulation.

Linearization of dependence of phase incursion on a distance in case of deviation of phase characteristics of retransmitter channels

There are obtained dependences of phase incursion of retransmitting meter signal, obtained in case of deviations of retransmitter phase characteristics from nominal values. New method of compensation of deviations is supposed for the case of linear law of dependence of phase shift from distance to the controlled object, when it considerably reduces an output error. Replacement of phase shift change is considered taking into account the possibility of processing algorithm modification. It is also shown the necessity of some additions for the input phase shifter circuit.