超低静态电流热插拔控制器

LTC4231允许电路板或电池安全地从2．7～36V系统中插入和拔出。LTC4231控制一个外部N沟道MOSFET,以平缓地给电路板电容器加电,从而避免瞬态放电、连接器损坏和系统干扰。器件在正常工作时静态电流仅为4μA,在停机模式则降至0．3μA。为确保低电流工作,欠压和过压阻性分压器连接至一个选通接地,从而将其平均吸收电流降低50倍。     

基于CPLD的短路电流检测与保护系统硬件电路设计

传统依靠电流幅值判断短路故障的方法,在大电流情况下局限性明显,判断时间延长导致整个系统在大的故障电流情况承受较长的时间,增大了系统运行的风险系数。文中提出了一种电流上升率结合电流幅值的方法作为短路判断依据,在分析电流检测和保护工作原理的基础上,设计了基于CPLD的短路电流早期检测和保护系统硬件电路,通过搭建混合式微网智能断路器实验平台,验证了该硬件电路的可靠性。     

基于TPS2491的热插拔保护电路设计

文章对主流热插拔控制策略进行了比较分析,在介绍热插拔控制器TPS2491功能结构后,以24V电源背板总线数据采集卡为设计实例,详细介绍了基于TPS2491进行热插拔保护电路的设计过程,并对设计电路进行了测试验证,验证结果表明设计电路可有效抑制热插拔过程中的浪涌电流.     

基于TPS2301的热插拔电路设计

简要介绍了快速热插拔器件TPS2301的主要特点,给出了一种基于TPS2301的热插拔控制电路的设计方法,同时就设计要点进行了详细的分析。     

ADM4210热插拔控制器的原理及应用

ADM4210器件构成的热插拔保护电路,为电路提供欠压、过压、过流和短路保护,能够在不响应工作底板正常运行情况下,实现板卡的热插拔.介绍了ADM4210的主要特性、工作原理及应用电路设计.     

LTC4222：双路热插拔(Hot Swap)控制器

Linear推出双路热插拔（Hot Swap）控制器LTC4222,用于保护具有多个范围为2．9V至29V的负载电源电压的电路板。通过控制外部N沟道MOSFET以在加电时限制浪涌电流,可实现从一个带电的两电源背板安全地把电路板插入和拔出。LTC4222适合于众多电子断路器、计算机／服务器和平台管理应用。     

ADM4210热插拔控制器的原理及应用

ADM4210器件构成的热插拔保护电路,为电路提供欠压、过压、过流和短路保护,能够在不响应工作底板正常运行情况下．实现板卡的热插拔。介绍了ADM4210的主要特性、工作原理及应用电路设计。     

基于LT1641的双路热插拔电路设计

针对某大型数据系统带有双路电压结构插件板的具体情况,给出了用LT1641热插拔控制器来进行热插拔电路设计的具体方法。同时给出了基于LT1641来实现两部分电路互锁的具体电路．最后给出了对该电路进行实验测试的测试波形结果。     

热插拔控制器实现双极性处理

有些应用场合需要使用一个热插拔控制器、一个断路器或者两者都要使用,以适应双极性直流输入电源干线.在某些使用热插拔控制器的情况下,这种要求仅仅出于对起动电流的考虑.要消除连接器的应力和电源干线的干扰,就必须控制起动电流.另外一些应用场合在某一电源因某种原因发生故障时就会出现问题.     

栅极电阻对GaN MOSFET瞬态特性的影响研究

为了研究栅极电阻对GaN MOSFET的开关速率和输出特性中出现振荡的影响,首先利用MOSFET的基本公式对其导通和关断时的输出瞬态电流进行了理论推导,然后通过实验平台测试GaN MOSFET的瞬态电流值,且与理论值对比,验证栅极电阻带来的影响。实验结果表明,GaN MOSFET的瞬态电流值实验值与理论值基本吻合,在导通和关断时,GaN MOSFET的输出瞬态电流和输出电流的高频震荡均随栅极电阻的增加而减小。栅极电阻从10 Ω变化到100 Ω时,导通时开关速率上升率占总开关速率上升率的84.7%,关断时开关速率下降率占总开关速率下降率的54.06%。在栅极电阻为10~100 Ω范围内,GaN MOSFET具有较快的开关速度。     

变电站设计中短路电流的计算与分析

变电所设计中,为了电气设备、载流导体的选择、继电保护、自动化装置的整定、限制短路电流措施确定等目的,往往都需要先进行短路电流的计算。准确地进行短路电流计算就能根据变电站电力系统的实际情况合理地确定限制短路电流的方案,或者限制某种运行方式的出现,得到既可靠又经济的主接线方案。短路电流主要包含有三相短路电流、两相短路电流和单相短路电流。本论文通过某工厂变电所的设计,详细地介绍了短路电流的计算原则,得出了一种切实可行的短路电流计算方法。     

The superlinearity of the short-circuit current oflow-resistivity-concentration solar cells

It has been observed that Si solar cells respond superlinearly to irradiance while GaAs behaves linearly. Computer analysis of superlinear characteristics of short-circuit current with irradiances above 1 sun for low-resistivity Si concentrator cells has shown the importance of the base electric field in enhancing the collection efficiency of minority carriers generated in the base region. The effect of the base electric field can be incorporated into effective upstream and downstream diffusion lengths. The effective downstream diffusion length increases from 223 μm at one sun to near 1000 μm at 1000 suns in one case. Collection of minority carriers in the base alone due to the enhanced diffusion lengths is sufficient to explain the observed superlinearity     

热插拔控制器构成限流电路

为避免电源在系统出现短路或过载时损坏,常采用限流电路为电源提供保护.针对这种应用,集成电路制造商提供了内置P沟道MOSFET和限流门限可调的芯片,这些芯片大多用于5V系统,将系统的最大电流限制在2A以内,电流精度较低(20%至50%).利用具有电流调节功能的"热插拔控制器"可构成高精度的通用限流电路(图1),外部MOSFET和电流检测电阻使该类芯片可用于3V至12V供电系统,CTIM引脚接地,抑制芯片的双速/双电平检测功能,使芯片处于开启模式.依照下式选择检流电阻、设置限流门限:ILIM=(200mV)/RSENSE(RSENSE 为检流电阻)     

Improved hysteresis band current controller

A new hysteresis band current controller for voltage source inverters is presented. This new technique, which has been experimentally verified, is based on the use of a second input current error derivative for the selection of the zero voltage vectors V_0,7 , which greatly reduces the inverter switching frequency     

Effect of thickness on short-circuit current of silicon solar cells

It has been found that the parameters of present high performanceN/Psilicon solar cells are such that even small reductions in the thickness of the cells result in noticeable decreases of the short-circuit current due to lower collection efficiency at long wavelengths. Theoretical and experimental results of an investigation into the change of short-circuit current as function of thickness are discussed. This effect is studied in dependence on the spectral distribution of the irradiating light for three commonly used types of light source as well as on the minority carrier lifetime and mobility in the base region of the solar cell. It is noteworthy that the differences in short-circuit current are eliminated by moderate damage due to nuclear particle radiation.     

Exchange switching of a magnetic junction by a current pulse

Results of numerical simulation of switching of a magnetic transition induced by a spin-polarized current pulse in the presence of an external magnetic field for a current density and a field strength that are lower than the corresponding threshold values are presented. The magnetic field regenerates the system and drives it to the threshold of an orientation phase transition, which simplifies exchange switching induced by a current pulse. This switching is characterized by the same locality as the exchange interaction, i.e., it is local at atomic lengths. It is demonstrated that there exists the possibility of switching with a controllable delay with respect to the current pulse.     

A novel SVM-based hysteresis current controller

In this paper, a novel space vector modulation (SVM)-based hysteresis current controller (HCC) for squirrel cage induction motors is proposed. This technique utilizes all advantages of the HCC and SVM technique. The controller determines a set of space vectors from a region detector and applies a space vector selected according to the main HCC. A set of space vectors including the zero vector to reduce the number of switchings is determined from the sign of the output frequency and output signals of three comparators with a little larger hysteresis band than that of the main HCC. A simple hardware implementation is proposed and experimental results of the SVM-based HCC are also shown     

An improved space-vector-based hysteresis current controller

In this paper, an improved space-vector-based hysteresis current controller (SVBHCC) is proposed. The controller determines a set of space vectors from a region detector and applies a space voltage vector selected according to the main HCC. A set of space vectors including the zero voltage vector to reduce the number of switchings is determined from the information of the current errors, which are wider than those of the main HCC. A simple hardware implementation is proposed and the good experimental results of the SVBHCC for a squirrel cage motor are also shown