怎样选用元器件讲座（九）片状光电耦合器

本文介绍国产GH4020系列片状光电耦合器,其外形及管脚排列如图1所示。电路图形符号如图2所示。由图看出,该系列光电耦合器和普通产品一样,也是一种电—光—电的转换器件。其输入端是红外发光二极管(GaAs),输出端的受光器件是硅光电三极管。引出端共有四个:输入端的“—”、“ ”,表示发光二极管的极性;输出端的“E”、“C”表示光电三极管极性。输入端与输出端之间耐压通常高达1kV以上。GH4020系列片状光电耦合器的主要参数如附表所示。该产品按电流传输     

光电耦合器使用常识

简易测试方法 由于光电耦合器的组成方式不尽相同，所以在检测时应针对不同的结构特点，采取不同的检测方法。例如，在检测普通光电耦合器的输入端时．一般均参照红外发光二极管的检测方法进行。对于光敏三极管输出型的光电耦合器．检测输出端时应参照光敏三极管的检测方法进行。     

光电耦合器传输比衰变分析

文章在理论和实验的基础上，对光电耦合器的电流以传输比衰变的原因进行了全面的分析，并建立了数学模型，为可靠地应用光电耦合器提供了工程设计的依据。     

光电器件

安华高科技推出业内能效最高的1MBd数字光电耦合器产品Avago Technologies(安华高科技)宣布,推出业内能效最高的1MBd数字光电耦合器产品,和目前产业标准1MBd数字光电耦合器比较,Avago紧凑的ACPL-M50L低功耗单通道光电耦合器可以节省工作电流达80%,这     

高压下陶瓷空封光电耦合器内部气体放电电流特性研究

陶瓷空封光电耦合器存在高压下的内部气体放电,分析其放电电流特性有助于器件可靠性研究。提出了基于体电流和气体放电电流的陶瓷空封光电耦合器漏电流模型,并针对高压下漏电流测试能力不足的现状,设计了基于悬浮供电的漏电流检测系统,通过对高压下器件漏电流的测试及对比分析,实现了对内部气体放电电流特性的定量评估。     

光电耦合器辐照损伤的噪声检测

分析了光电耦合器辐照噪声特性,提出了光电耦合器辐照噪声的检测方法,搭建了光电耦合器噪声测试电路.实验结果表明,噪声参量比电参量更能灵敏真实地反映光电耦合器的辐照损伤程度.     

泰科电子全新太阳能板接地连接器帮助实现快速简便安装

AvagoTechnologies（安华高科技）宣布,推出业内能效最高的1MBd数字光电耦合器产品,和目前产业标准1MBd数字光电耦合器比较,Avago紧凑的ACPL—M50L低功耗单通道光电耦合器可以节省工作电流达80％,     

不同偏置条件下光电耦合器的总剂量效应

开展了4N49光电耦合器不同辐照偏置条件下的辐照实验,结果表明:电流传输比的下降幅度与辐照期间的偏置条件有关,处于工作状态的光电耦合器比短路状态的总剂量效应要弱,其根源是光电耦合器的LED施加了电流,而与光敏晶体管的偏置状态关系不大;电流传输比随偏置条件的变化关系是由初级光电流决定的,而C-B区光响应度是初级光电流退化的主导因素.     

光电耦合器总剂量辐照的噪声表征

 本文在研究光电耦合器工作原理、辐照理论及1/f噪声理论的基础上,分析了光电耦合器辐照噪声产生机理及特性,建立了光电耦合器总剂量辐照损伤噪声模型.研究结果表明,随着辐照总剂量增强, LED及光敏管氧化层中引入的氧化层陷阱密度增多,载流子数涨落增强,从而使电压噪声功率谱密度增加.实验结果验证理论分析的正确性,电压噪声功率谱密度可作为光电耦合器辐照损伤表征参量.     

光电耦合器电流传输比的噪声表征

光电耦合器中可俘获载流子的陷阱密度是影响其电流传输比(CTR)的重要因素,并与器件可靠性有密切关系.在器件内部的多种噪声中,1/f噪声可有效地表征器件陷阱密度.本文在研究光电耦合器工作原理以及1/f噪声理论的基础上,建立了光电耦合器的CTR表征模型和1/f噪声模型.在输入电流宽范围变化的条件下,测量了器件的电学噪声和CTR变化,实验结果验证了以上模型的正确性.将CTR模型与噪声模型相结合,得到了CTR与1/f噪声之间的关系.此关系应用于对光电耦合器辐照实验结果的分析,实验结果与理论得到的结论一致.理论与实验结果表明,噪声幅值越大,电流指数越接近于2,则器件的可靠性越差,相同工作条件下CTR的老化衰减量越大,其失效率显著增大.从而证明噪声可表征光电耦合器的CTR并能准确地反映器件的可靠性.     

A modified model of the light amplifying optical switch (LAOS)

A new analytical circuit model of the light amplifying optical switch (LAOS) is proposed. The static I-V curve, the switching voltage, and the input-output characteristics can be calculated from this model. The model is based on deriving an expression for the nonlinear current gain of the heterojunction phototransistor (HPT). The switching mechanism and the I-V characteristics of the LAGS is studied in the context of optical and/or electrical feedback. The nonlinear current gain of the HPT, and the Early effect are the main factors which are responsible for the thyristor-like characteristics of the LAOS. An external feedback resistor is also added to achieve the appropriate switching condition and build up the feedback mechanism. A bistable system using a LAGS is also studied as well as the device hysteresis width     

A phototransistor optical isolator noise model

A noise model for the phototransistor optical isolator is presented and used to predict optical isolator noise performance. Results are shown to agree with existing experimental data on phototransistor optical isolator noise. The model presented includes burst noise, flicker noise and shot noise.     

基于偏振调制型全光纤电流互感器的研究

随着电力系统输电电压等级和传输容量的不断提高,传统的电磁式电流互感器暴露出诸多问题已难以满足当今社会的需要。本系统通过对光纤电流互感器的理论基础进行了深入的研究,并在此基础上建立了光纤电流互感器数学模型;根据模型设计了光纤电流互感器光路系统,并根据光路特点选择了相关器件;根据光路系统输出信号的特点,设计了激光器驱动电路和光纤电流互感器信号检测电路,对检测电路的性能进行了单独测试;最后,设计了光纤电流互感器准确度测试系统,并对所设计的光纤电流互感器系统进行了整体测试。测试结果表明,在相同的测试环境下,该光纤电流互感器的输出具有极好的线性,测试结果符合 IEC 0.2S 级。     

The avalanche phototransistor—A novel type of radiation detector and its potential use in optical communication systems

The possibility of triggering avalanche transistors by optical signals and the resulting electrical characteristics are presented. These avalanche phototransistor (APT) detectors are capable of generating nanosecond output pulses at high current levels. A series connection of an APT and injection laser is shown to operate as a simple PCM-regenerator circuit in optical communication systems.     

Gain of a heterojunction bipolar phototransistor

Analytical expressions have been derived for the collector current, optical gain, and quantum efficiency for a heterojunction, bi-polar phototransistor (HPT). These expressions can be utilized to optimize the current gain and quantum efficiency for HPT design. The presence of avalanche multiplication in the base-collector junction has been taken into account and shown to be a significant factor in determining the gain of an InGaAs/InP phototransistor. Experimental results of optical gain versus the collector-emitter voltage can only be explained in terms Of avalanche multiplication.     

The lambda bipolar phototransistor-analysis and applications

An analytic model for the I-V characteristic of the lambda bipolar phototransistor (LBPT) is developed in which the characteristic parameters, such as the peak voltage, peak current, differential negative resistance, valley voltage, and valley current, are expressed in terms of the known device parameters and photocurrent. It is shown that the valley current of the new device in the dark is much smaller than the saturation dark current of the conventional bipolar phototransistor and that the differential negative resistance region can be varied for wide range by controlling the fabrication processes. Comparisons between the characteristics of the fabrication devices and the developed model have been made and satisfactory agreement has been obtained. Moreover, some interesting applications of this new device in photodetection are also presented and discussed.     

异质结光电晶体管增益特性分析

从理论上分析了用宽带隙材料作发射区的ｎ－ｐ－ｎ光电晶体管可提高其发射区注入效率，就ｎ－ｐ－ｎ光电三极管的增益特性进行了研究，给出了光增益与电增益的关系。     

MEXTRAM modeling of Si-SiGe HPTs

The integration of the photodetector is essential for optical communication chips. The heterojunction phototransistor (HPT) is integrable with the SiGe HBT process and can be modeled by a modified MEXTRAM model for the circuit simulation. The impact ionization to obtain an extra gain for the optoelectronic conversion and the "early voltage reduction" under constant illumination are well modeled in a modified model. The base recombination current (nkT current) and the substrate contact to enhance the HPT speed are incorporated in ac model. It shows a good agreement between measurement and simulation.     

An a-Si:H/a-Si,Ge:H bulk barrier phototransistor with a-SiC:Hbarrier enhancement layer for high-gain IR optical detector

The design and fabrication of a high-gain amorphous silicon/amorphous silicon germanium (a-Si:H/a-Si,Ge:H) bulk barrier phototransistor for infrared light detection applications are reported. The a-Si,Ge:H material featured a lower energy gap and is suitable for the absorption of longer wave light, but it also leads to a low breakdown voltage and high dark current. An additional a-SiC:H thin-film layer was used at the collector/base interface in the conventional amorphous bulk barrier phototransistor to enhance the function of the bulk barrier and obtain high optical gain     

AlGaAsSb-InGaAsSb HPTs with high optical gain and wide dynamic range

Novel heterojunction phototransistors based on AlGaAsSb-InGaAsSb material systems are fabricated and their characteristics are demonstrated. Responsivity of a phototransistor is measured with applied bias voltage at four different wavelengths. The maximum responsivity around 1400 A/W and minimum noise equivalent power of 1.83/spl times/10/sup -14/ W/Hz/sup 1/2/ from this phototransistor with bias of 4.0 V at a wavelength of 2.05 /spl mu/m were measured at 20/spl deg/C and -20/spl deg/C, respectively. Noise equivalent power of the phototransistor is considerably lower compared with commercially available InGaAs p-i-n photodiodes. Collector current measurements with applied incident power are performed for two phototransistors. Currents of 400 nA at low intensity of 0.425 /spl mu/W/cm/sup 2/ and of 30 mA at high intensity of 100 mW/cm/sup 2/ are determined. Collector current increases nearly by five orders of magnitude between these two input intensities. High and constant optical gain of 500 in the 0.46-nW to 40-/spl mu/W input power range is achieved, which demonstrates high dynamic range for such devices at these power levels.