Multi-mode controller IC for soft-switched flyback converter with high efficiency over the entire load range

This paper presents a multi-mode control scheme for a soft-switched flyback converter to achieve high efficiency and excellent load regulation over the entire load range. At heavy load, critical conduction mode with valley switching （CCMVS） is employed to realize soft switching so as to reduce turn-on loss of power switch as well as conducted electromagnetic interference （EMI）. At light load, the converter operates in discontinuous conduction mode （DCM） with valley switching and adaptive off-time control （AOT） to limit the switching frequency range and maintain load regulation. At extremely light load or in standby mode, burst mode operation is adopted to provide low power consumption through reducing both switching frequency and static power dissipation of the controller. The multi-mode control is implemented by an oscillator whose pulse duration is adjusted by output feedback. An accurate valley switching control circuit guarantees the minimum turn-on voltage drop of power switch. The prototype of the controller IC was fabricated in a 1.5-μm BiCMOS process and applied to a 310 V/20 V, 90 W flyback DC/DC converter circuitry. Experimental results showed that all expected functions were realized successfully. The flyback converter achieved a high efficiency of over 80% from full load down to 2.5 W, with the maximum reaching 88.8%, while the total power consumption in standby mode was about 300 mW.     

Digitally controlled boost PFC converters operating with large scale load fluctuations

When boost power factor correction （PFC） circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor cur- rent mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.     

On-chip boost regulator with projected off- and on-time control

The boost type power supplies are widely used in portable consumer electronics to step up the input voltage to adapt for the high voltage applications like light-emitting diode （LED） driving and liquid crystal display （LCD） biasing. In these applications, a regulator with small volume, fewer external components and high efficiency is highly desired. This paper proposes a projected off- and on-time boost control scheme, based on which a monolithic IC with an on-chip VDMOS with 0.2 Ω on-state resistance RDS-ON was implemented in 1.5 μm bipolar-CMOS-DMOS （BCD） process. A 12 V, 0.3 A boost regulator prototype is presented as well. With projected off-time and modulated on-time in continuous conduction mode （CCM）, a quasi fixed frequency, which is preferred for ripple control, is realized. With projected on-time and modulated off-time in discontinuous conduction mode （DCM）, pulse frequency modulation （PFM） operation, which is beneficial to light load efficiency improvement, is achieved without extra control circuitry. Measurement results show that an efficiency of 3% higher than that of a conventional method under 0.5 W output is achieved while a step load transient response comparable to that of current mode control is maintained as well.     

High Speed Column-Parallel CDS/ADC Circuit with Nonlinearity Compensation for CMOS Image Sensors

A high speed column-parallel CDS/ADC circuit with nonlinearity compensation is proposed in this paper.The correlated double sampling (CDS) and analog-to-digital converter (ADC) functions are integrated in a threephase column-parallel circuit based on two floating gate inverters and switched-capacitor network.The conversion rate of traditional single-slope ADC is speeded up by dividing quantization to coarse step and fine step.A storage capacitor is used to store the result of coarse step and locate the section of ramp signal of fine step,which can reduce the clock step from 2 n to 2 (n/2+1).The floating gate inverters are implemented to reduce the power consumption.Its induced nonlinear offset is cancelled by introducing a compensation module to the input of inverter,which can equalize the coupling path in three phases of the proposed circuit.This circuit is designed and simulated for CMOS image sensor with 640×480 pixel array using Chartered 0.18μm process.Simulation results indicate that the resolution can reach 10-bit and the maximum frame rate can reach 200 frames/s with a main clock of 10MHz.The power consumption of this circuit is less than 36.5μW with a 3.3V power supply.The proposed CDS/ADC circuit is suitable for high resolution and high speed image sensors.     

A novel voltage output integrated circuit temperature sensor

The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two-terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error of less than ±1.0℃ over a temperature range from -50℃ to +125℃. In addition to all the features that conventional IC temperature sensors have, the new device also has very low static power dissipation ( 0.5 mW ) , low output impedance ( less than 1Ω), excellent stability, high reproducibility, and high precision. The sensor's circuit design and layout are discussed in detail. Applications of the sensor include almost any type of temperature sensing over the range of -50℃-+125℃. The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy. Due to the excellent performance and low cost of this sensor, more applications of the sensor over wide temperature range are expected.     

Analysis Model of Dynamic Response on the Circular Caisson Breakwater Under Random Wave

The random wave load is applied to dynamic response analysis of circular caisson breakwater. The motion process of circular caisson breakwater is classified as rotation motion mode and rotation-and-sliding motion mode. The dynamic model system composed of damper-antislider to control the lateral sliding is introduced, and corresponding dynamic equations of two motion modes are established. The formulas to calculate added mass and new conversion relation of the unit rotational stiffness coefficient are put forward according to the characteristic of the circular caisson breakwater. An engineering case is calculated by a program compiled in Fortran language using proposed dynamic model and method. The validity of the model is calibrated.     

Position Sensorless Control for Permanent Magnet Synchronous Motor Using Sliding Mode Observer

An approach of position sensorless control for permanent magnet synchronous motor （ PMSM ） is put forward based on a sliding mode observer. The mathematical model of PMSM in a stationary αβ reference frame is adopted, and the system is controlled by the digital signal processor （ DSP; TMS320LF2407 according to the control achieve closed loop operation of the motor, the stator theory of sliding mode observer. In order to magnetic field should be vertical with the rotor magnetic field and be synchronous with rotor rotating, so the position and speed of PMSM is estimated in real time and the estimated position is modified continuously. The simulation results indicate that the proposed observer has high precision is more robust to the parametric variation and load in estimation of PMSM position and speed, and torque disturbance.     

Robust Adaptive Control Design for Rotorcraft Unmanned Aerial Vehicles Based on Sliding Mode Approach

This paper presents a nonlinear robust control design method for a generic rotorcraft unmanned aerial vehicle（RUAV）. The control objective is to let the RUAV track some pre-defined time-varying position and headingtrajectories. The proposed controller employs feedback linearization process to realize the dynamic decoupling controland applies adaptive sliding mode control to compensate for the parametric uncertainties and external disturbances.The global asymptotical stability is proved via stability analysis. Compared with the cascaded controller, the proposedcontroller demonstrates a superior tracking performance and robustness through numerical simulation in the presenceof parametric uncertainties and unknown disturbances.     

Impact of load impedance on the performance of a thermoacoustic system employing acoustic pressure amplifier

An acoustic pressure amplifier （APA） is capable of improving the match between a thermoacoustic engine and a load by elevating pressure ratio and acoustic power output. A standing-wave thermoacoustic engine driving a resistance- and-compliance （RC） load through an APA was simulated with linear thermoacoustics to study the impact of load impedance on the performance of the thermoacoustic system. Based on the simulation results, analysis focuses on the distribution of pressure amplitude and velocity amplitude in APA with an RC load of diverse acoustic resistances and compliance impedances. Variation of operating parameters, including pressure ratio, acoustic power, hot end temperature of stack, etc., versus impedance of the RC load is presented and analyzed according to the abovementioned distribution. A verifying experiment has been performed, which indicates that the simulation can roughly predict the system operation in the fundamental-frequency mode.     

Drivability improvements for a single-motor parallel hybrid electric vehicle using robust controls

For a single-motor parallel hybrid electric vehicle, during mode transitions （especially the transition from electric drive mode to engine/parallel drive mode, which requires the clutch engagement）, the drivability of the vehicle will be signifi- cantly affected by a clutch torque induced disturbance, driveline oscillations and jerks which can occur without adequate controls. To improve vehicle drivability during mode transitions for a single-motor parallel hybrid electric vehicle, two controllers are proposed. The first controller is the engine-side controller for engine cranking/starting and speed synchronization. The second controller is the motor-side controller for achieving a smooth mode transition with reduced driveline oscillations and jerks under the clutch torque induced disturbance and system uncertainties. The controllers are all composed of a feed-forward control and a robust feedback control. The robust controllers are designed by using the mu synthesis method. In the design process, control- oriented system models that take account of various parameter uncertainties and un-modeled dynamics are used. The results of the simulation demonstrate the effectiveness of the proposed control algorithms.     

Design of a high efficiency boost DC-DC converter

An accurate circuit of PWM/PFM mode converting and a circuit of auto-adaptively adjusting dimension of power transistor are described. The duty cycle of the signal when the control mode converts can be gained accurately by using ratios of currents and capacitances, and an optimal dimension of power transistor is derived with different loads. The converter is designed by 0.35 μm standard CMOS technology. Simulation results indicate that the converter starts work at 0.8 V input voltage. Combined with synchronized rectification, the transfer efficiency is higher than 90% with full load range, and achieves 97.5% at rating output.     

中高压软启动控制器的设计

直接启动电动机会产生很强的冲击电流,降低了电动机的使用寿命,对电网也会造成很大的冲击.设计一种限流PI调节降压式软启动,该软启动以TMS320 F28335为控制核心,通过在同步信号作用下,采集电动机启动时电流、电压信号,对晶闸管触发角移相的控制实现电动机启动电压和电流的调节,电动机启动过程中的参数可以根据电动机不同负...     

A novel low-voltage high precision current reference based on subthreshold MOSFETs

INTRODUCTION With the development of modern electronics,there is a growing trend of designing a low-voltagehigh precision current reference in many mixed-signaland analog circuits such as data converters (Mehr andSinger, 2000; Oh et al., 2004), oscillators and PLLs(Razavi, 2001; Banba and Shiga, 1999). Low-costreasons need the reference to be realized in simplestandard CMOS logic process technology, withoutresorting to the use of BiCMOS process and specialdevices such as floating-g…     

A new broadband differential phase shifter fabricated using a novel CRLH structure

Broadband phase shifters are mostly proposed and fabricated based on the scheme proposed by Shiffman, which uses a coupled line with far ends connected together and a uniform transmission line to give a differential phase shift. Based on the unique dispersion property of the composite right/left-handed (CRLH) metamaterial structure, a new configuration is presented in this paper for fabricating the broadband differential phase shifter, which employs a novel CRLH metamaterial structure as one of the differential phase-shift arms, instead of the conventional coupled line. The new circuit can achieve a phase shift of 90° in an operational bandwidth as broad as one octave and its phase deviations are quite small. An original design of the novel broadband phase shifter is presented, in which the artificial CRLH structure was implemented by microstrip quasi-lumped elements. Both the simulated and measured results of the 90° broadband differential phase shifter are presented.     

基于数据质量控制的ETL

提出了一种基于数据质量进行控制的ETL技术,在传统的ETL操作流程中增加脏数据处理模块及抽样数据质量评估模块,并将数据质量控制思想融入到ETL的操作流程设计中,控制ETL过程的数据质量。实验表明,带有质量控制的ETL算法设计优化了ETL工作流程,提高了进入数据挖掘中数据的质量。     

基于FOT模式PFC电路设计的研究

提出了一种基于FOT模式的PFC电路设计方法,以L6562为控制芯片,给出了470W PFC主电路及控制电路方案。采用C语言编程的方式对电流等关键参数进行模拟计算,在满载情况下,对设计电路进行了实验验证。计算及实验结果表明,在优化参数：电感值350uH,固定关断时间为5us情况下,470W FOT模式PFC电路能有效减小输入电流谐波,提高功率因数。     

EDA技术及其应用

随着大规模集成电路技术和计算机技术的不断发展,电子技术得到了飞速发展,电子设计自动化（EDA）技术,加速了现代高科技发展的进程_从微电子技术、微电脑技术到信息技术等领域,EDA技术的含量正以惊人的速度上升,在电子系统设计上产生了具有里程碑意义的飞跃,为大规模可编程逻辑器件的应用奠定了基础．     

Compact wideband microstrip array antenna with beam squint

A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured impedance bandwidth (voltage standing wave ratio (VSWR)⩽2) is over 16%, which agrees well with the simulated one. It is a low-cost wideband design with compact simple structure, suited for military and commercial application.