对VN系列VMOS功率场效应管输入电容的改善设计

VN系列VMOS功率场效应管自1984年7月设计定型以来,用户以及本研制小组针对系列产品中普遍存在的问题作了一些探讨并提出了改进意见.其中主要一点是VN系列产品的输入电容(C_(?)过大的问题.VMOS功率场效应管目前主要用于各种微功率驱动电路、高频电路以及大容量电流源电路中,这些电路一般要求输入阻抗高,开关速度快,频率响应     

变截面场效应管

本文提出了一种具有渐变沟道“截面”(电导率)的新型场效应管.在通常的场效应管中,高频电流通过沟道时将因沟道电阻及其侧面电容的 R C效应而衰减,但是在一只 GaAs变截面场效应管中,当控制沟道场强使得其中的电子微分迁移率取负值时,高频电流振幅将沿着沟道递增,从而得出一种三端负阻放大器,其极限频率是很高的.     

二极管正向浪涌电流测试方法

该文讲述了二极管正向浪涌电流测试的基本要求和标准测试方法,针对标准测试方法存在的不足,设计实现了采用信号控制、电容储能和大功率场效应管晶体管电流驱动的电路解决方案,简洁而又高效地实现了二极管正向浪涌电流的测试。     

工作电流达10A的VN系列VVMOS大功率场效应管的设计及制造

本文提出了工作电流达10A的VVMOS场效应管的设计方案、制造方法,并给出管子特性曲线.一九八四年七月二日至四日.由电子工业部器件工业总公司主持,在西安召开了部级鉴定会,一致通过了VN系列VVMOS大功率场效应管生产鉴定.     

双注入结型场效应管的电流-电压特性

对新型半导体器件——双注入结型场效应管的电流－电压特性进行了详细分析，并得出解析表达式，为该器件的设计和应用提供了理论依据。     

双注入结型场效应管的电流—电压特性

对新型半导体器件－双注入结型场效应管的电流－电压特性进行了详细分析，并得出解析表达式，为该器件的设计和应用提供了理论依据。     

高压、高效率白光LED驱动电路的研究与设计

设计了一种高效率的高输入电压,恒定电流输出的白光LED驱动芯片.采用高压工艺,以脉宽调制(PWM)峰值电流的控制方式,实现了宽范围电压输入、恒定电流输出的LED驱动芯片的设计.内部集成了带隙电压基准源,产生0.25V的参考电压.芯片设计采用了高压横向扩散金属氧化物半导体场效应管(LDDMOS),设计了电压预调整电路,实现了输入电压范围在85V-400V间变化,输出电流在1毫安到1安培间设定.芯片仿真结果显示电能转换效率最高可达90%以上.     

场效应管的特性、检测及使用（下）

六、场效应管的使用由于场效应管的输入阻抗高,适用于多级放大电路的输入级,尤其对于高内阻信号源以及信号电流很小的情况下,采用场效应管才能有效地放大。场效应管是电压控制元件,当V_(DD)和R_D选定后,静态工作     

结型场效应可调恒流晶体管

本文根据肖克莱理论分析了使结型场效应管恒流的原理,介绍了可调恒流晶体管3DH的设计及应用.本器件主要优点为:恒流稳定可调,动态电阻可达≥5MΩ,工作电压范围宽.其特性十分接近理想电流源.是一种适用范围很广的新颖器件.     

三相电机电流检测系统的设计及实现

为了方便对分布在各处的三相电机工作电流的相位进行检测,文章设计了一种分布式体系结构的电机检测系统。系统包括上位机和下位机2个部分。上位机程序采用Delphi语言编写,通过上位机向各个下位机发送命令,同时收集下位机发送来的数据并储存。下位机设备是以LPC2013微控制器为核心的数据采集设备,其软件部分以RT-Thread实时操作系统为基础进行设计,实现与上位机的通信、数据采集,得到电机工作电流和相位差。上位机与下位机设备的通信基于CAN总线。     

基于TOP Switch Ⅱ的开关电源设计

介绍以TOP227Y为核心制作实验反激式稳压电源的工作原理,通过TL431与光耦PC817闭环反馈来控制TOP控制端电流大小,改变脉冲占空比,使开关电源在负载变化和输入电压变化时能量状态、电路状态的稳定。合理改进变压器设计以及制作工艺,减小开关电源电磁干扰,减小输出电压的纹波含量。     

A PWM DC-DC converter with optimum segmented output stage and current detector

High efficiency is very important for DC-DC power supplies in portable applications. A PWM DC-DC converter with optimum segmented output stage is proposed in this paper whose efficiency at light load is improved. The segmented output stage is optimally divided into 5 small segments plus 4 big segments. The segmented number of the output stage can be adaptively regulated according to the load current. Moreover, two current detector circuits are simultaneously adopted to form a mixed load current sensor in the converter to improve the detecting accuracy. A segmented current SenseFET (SCS) is used to sense the load current in continuous current mode, and a time digital converter with digital judgement (TDC-D) is designed to detect the load current in discontinuous current mode. The structure of the proposed PWM converter with optimum segmented output stage and mixed load current detector circuits is described in this paper, which has been implemented in a 0.13 μm CMOS process. Simulation and testing results show that the output stages of the PWM converter can self transit from one segment stage to another segment stage according to the load condition. And the maximum efficiency improvement of the proposed converter can reach 15%.     

基于电流型控制的LED恒流源分析与设计

设计了一种输出功率约50W的LED恒流源驱动模块,其负载为由多只LED管(每只功率为1W)采用混联方式组成的LED阵列。通过对其电流型反激式变换及恒流控制电路的设计与试制,并在不同输入电压下,改变负载测试,可看出其电流变化规律基本相似。随着负载变小,输出电压升高,输出电流逐渐减小,输出电流稳定度达4.6%。在一定负载时,输出电压值保持在47.2V左右,电压纹波峰-峰值约为400mV。电流波动约0.05A,输出电流稳定可靠,可用于对多只串并混联的LED阵列驱动供电。     

基于电流型控制的LED恒流源分析与设计

设计了一种输出功率约50W的LED恒流源驱动模块, 其负载为由多只LED管(每只功率为1W)采用混联方式组成的LED阵列。通过对其电流型反激式变换及恒流控制电路的设计与试制, 并在不同输入电压下, 改变负载测试, 可看出其电流变化规律基本相似。随着负载变小, 输出电压升高, 输出电流逐渐减小, 输出电流稳定度达4.6%。在一定负载时, 输出电压值保持在47.2V左右, 电压纹波峰-峰值约为400mV。电流波动约0.05A, 输出电流稳定可靠, 可用于对多只串并混联的LED阵列驱动供电。     

电流型PWM控制器UC3844及其在微机电源中的应用

针对电压型脉宽调制器(PWM)控制器只有电压控制环、电流变化滞后电压变化、系统响应速度慢、稳定性差等固有缺点,介绍了既有电压控制环、又有电流控制环的新型电流型PWM控制器.分析了电流型PWM控制器与电压型PWM控制器的控制原理,比较了二者之间的优缺点;介绍了电流型PWM控制器UC3844的工作原理,并应用电流型PWM控制器UC3844设计了微机电源,指出了设计中应该注意的问题.结果表明,由电流型PWM控制器构成的微机电源具有良好的电压调整率、负载调整率和系统稳定性等优点.     

A Transient-Enhanced Low-Quiescent Current Low-Dropout Regulator With Buffer Impedance Attenuation

This paper presents a low-dropout regulator (LDO) for portable applications with an impedance-attenuated buffer for driving the pass device. Dynamically-biased shunt feedback is proposed in the buffer to lower its output resistance such that the pole at the gate of the pass device is pushed to high frequencies without dissipating large quiescent current. By employing the current-buffer compensation, only a single pole is realized within the regulation loop unity-gain bandwidth and over 65deg phase margin is achieved under the full range of the load current in the LDO. The LDO thus achieves stability without using any low-frequency zero. The maximum output-voltage variation can be minimized during load transients even if a small output capacitor is used. The LDO with the proposed impedance-attenuated buffer has been implemented in a 0.35-mum twin-well CMOS process. The proposed LDO dissipates 20-muA quiescent current at no-load condition and is able to deliver up to 200-mA load current. With a 1-muF output capacitor, the maximum transient output-voltage variation is within 3% of the output voltage with load step changes of 200 mA/100 ns.     

一款采用超前相位补偿技术的低压差线性稳压器

设计了一种具有高稳定性、能够驱动较大负载电流的低压差线性稳压器(LDO)电路,输入电压为3.0~6.0 V,输出电压为2.8 V。采用超前相位补偿技术,产生一组零极点对,零点补偿前面环路中的极点,使得LDO电路具有稳定的环路结构,得到稳定的输出电压。基于CSMC 0.25μm EN BCDMOS工艺完成电路和版图的设计。电路仿真结果表明电路的负载调整率为0.03%/A,线性调整率为0.13%/V,最大驱动的负载电流为10 mA。在不同负载条件下,LDO环路的最差相位裕度能够达到64.1°。     

Steady-state and large-signal design of current-programmed DC-DCconverters

A new method for steady-state design of current-programmed-mode (CPM) DC-DC converters is presented. The method uses a set of equations derived based on the relationships between line voltage, load current, control current, and the stabilizing artificial ramp. The set of normalized equations are verified by a fast large-signal simulation and experimental measurement. These equations are plotted on the converter DC output plane (a graph of output current versus output voltage) in which characteristic curves related to different artificial ramps and boundaries of different operating modes are indicated. A general design procedure is presented for a CPM converter with both input voltage and output resistive load varied. By this means, the design time can be significantly reduced, and systematic design trade-offs can be made to ensure correct converter operation over the desired range of line and load variation     

一种DC/DC转换器的短路保护电路设计

针对负载短路会对DC/DC造成性能不稳定或损坏的情况,提出一种新型短路保护电路,有效地避免了传统电路在短路时大电流输出造成的能量浪费。该保护电路采用在负载短接时,通过改变电流限比较器输入端基准电压达到降低电路最大输出电流的措施。采用0.35 μm BCD工艺将该电路应用于一款高压同步BUCK型DC/DC转换器中,specter仿真结果表明,当负载短路时,该芯片的短路电流只有30 mA,与传统保护电路相比,降低了短路时的输出电流,达到节约能量的目的。     

A dual mode charge pump with adaptive output used in a class G audio power amplifier

A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented.According to the amplitude of the input signals,the charge pump has two level output voltage rails available to save power.It operates both in current mode at high output load and in pulse frequency modulation (PFM) at light load to reduce the power dissipation.Also,dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range.The prototype is implemented in 0.18μm 3.3 V CMOS technology.Experimental results show that the maximum power efficiency of the charge pump is 79.5%@ 0.5x mode and 83.6%@ lx mode.The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control.An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results.