Temperature Characteristics of BJMOSFET

The resolution expression for the temperature dependence of the current and threshold voltage is deduced as well as the analysis of temperature characteristics of BJMOSFET. Equivalent circuit of analysis and simulation has been established for the BJMOSFET temperature characteristics. By using the general circuit simulation software of PSpice9 and computer simulation, characteristic graphs of the BJMOSFET output characteristic, transient characteristic and amplitude-frequency characteristic with temperature variation are obtained. The results accorded very good with theoretical analysis and proved that BJMOSFET has better temperature characteristics than traditional MOSFET.     

BJMOSFET温度特性分析及计算机模拟

对兼有双极型和场效应型两种器件特点的双极MOS场效应晶体管(BJMOSFET)的电流和阈值电压的温度特性进行了详细分析．推导出它们随温度变化率的解析表达式。建立BJMOSFET的直流小信号模拟分析等效电路和频率特性模拟分析等效电路,采用通用电路仿真软件PSpice9,对BJMOSFET的输出特性、瞬态特性和幅频特性随温度的变化进行了计算机模拟,得到了随温度变化的特性曲线,并且理论分析与计算机模拟取得了一致的结果。相对传统MOSFET,证明了BJMOSFET具有较好的温度特性。     

基于SOI的双极场效应晶体管

在分析了双极型晶体管和场效应晶体管各自的特点和不足后，介绍了一种既具有双极型晶体管较大电流容量和功率输出，又具有场效应晶体管高输入阻抗的电子器件——双极MOS场效应晶体管(BJMOSFET)，同时指出体硅BJMOSFET的阳极扩散区与衬底之间存在较大的漏电流，可产生较大的寄生效应。提出了一种新型固体电子器件——基于SOI的BJMOSFET，分析了其工作原理j与体硅BJMOSFET比较，由于SOI技术完整的介质隔离避免了体硅器件中存在的大部分寄生效应，使基于SOI的BJMOSFET在体效应、热载流子效应、寄生电容、短沟道效应和闩锁效应等方面具有更优良的特性。     

Numerical Simulation of BJMOSFET on Current-Voltage Characteristics

A new power MOSFET Structure with a pn junction--Bipolar Junction MOSFET (BJMOSFET) has been proposed. The device has the advantages of both BJT and FET. The numerical model of the I-V characteristics of BJMOSFET has been obtained on the basis of both numerical and analytical methods. With the software package of Mathematic, we firstly calculate the gain factor, and then simulate the voltage tranmission, voltage output and voltage transfer's characteristic graphs of the BJMOSFET. The simulation result indicates that BJMOSFET has the current density, which is about 25% larger than the power MOSFET, under the same operating conditions and with the same structure parameters, except that the threshold voltage increase a little.     

一种新的不受寄生电容影响的电容式传感器接口电路

给出了一种新的用于微小电容检测的接口电路 .在电荷传送电路的基础上,引入了一个用于参考微变电容读出的电荷传送电路部分,将检测电路与参考电路的输出进行差分放大,从而大大提高了电路的稳定性和检测灵敏度,同时此电路也保持了电荷传送电路检测微小电容变化不受寄生电容影响的特性.     

放大电路频率特性的逆向启发式教学研究

"放大器的频率特性"是《模拟电子技术基础》课程中的教学难点,在学时分配有限的情况下该内容的教学方法是否得当将直接影响学生对于放大器特性的完整理解。遵照国内外主流教材,仍然以基本的单管共射放大电路为例,首先引出电路完整的电压放大倍数表达式,在启发学生思考中将频率特性的分析转变为对上、下限频率的简单求解;然后根据电容容抗的表达式对放大电路中的耦合电容与结电容进行分频段研究;分析RC低通、高通电路的频率特性及分别对应的上、下限频率,并很自然地引出晶体管的高频小信号Π形等效电路;最后根据学生的专业与学时有区别地化简等效电路,验证放大器的频率特性,得到放大电路的完整波特图。     

Millimeter wave monolithic high electron mobility (HEM) varactor diode-grid frequency tripler arrays

High Electron Mobility (HEM) varactor structures have been studied for millimeter-wave monolithic diode-grid frequency tripler array applications. The improved HEM varactor diode structures provide a highly nonlinear C-V characteristic (i.e., a steep slope of the C-V curve and a large capacitance ratio) which produces high harmonic generation efficiency and reduce the power requirement for efficiently pumping each device. The effects of the light illumination on the C-V characteristics of the Barrier-Intrinsic-N⁺ (BIN) varactor diode have also been studied and the results will be discussed in this paper. In the development of a monolithic diode-grid frequency multiplier array, the low-loss quasioptical configuration is used for the construction of the multiplier circuit. The study of the effects of the light illumination on the C-V characteristics of varactor diode is important in understanding the potential applications of the quasi-optical varactor diode-grid frequency multiplier array circuit.     

Design rules for an integratable low-power amplifier/filter combination

In this paper design rules for a circuit topology in which there is an inseparable combination of an amplifier and a filter characteristic, are presented. By intentionally using the capacitance of an already present input sensor for the filtering, the total required integrated capacitance is much less than that in circuits, which have a separately designed amplifier and filter function. Consequently, it is possible to have the advantage of a better integratability. Moreover, less complexity in the design is achieved. The presented circuit shows a current-to-voltage conversion and an inherently controllable second-order low-pass filter characteristic. A discrete realization has been designed to test the circuit. This circuit operates down to a 1 V supply voltage and the transfer shows a 1.8 M currentto-voltage conversion with a bandwidth of 6 kHz. Measurement results of this circuit show that a 63 dB dynamic range can be achieved with a total required integrated capacitance of only 31 pF.     

电磁干扰中元件的高频特性研究

电力电子设备产生的电磁干扰都会超过可接受的水平,所以要利用滤波电路降低他们产生的EMI,这些滤波电路由串联扼流圈和并联电容器构成低通滤波器,文章对EMI滤波元件的高频特性进行分析,给出了电容、电感、电阻等的高频特性、等效电路以及仿真曲线。得出的结论体现出与工频下不同的特性,对滤波设计有重要指导意义。     

微波倍频器的设计与研制

针对微波倍频器的实现途径,介绍了阶跃管倍频和三极管倍频的原理,其中三端非线性电阻微波倍频器可实现有增益倍频,且倍频效率高,稳定性好,在现代通信系统中有着广泛的应用前景。应用ADS软件对倍频电路进行优化仿真,利用集总参数电容和电感对阻抗进行匹配,设计利用晶体三极管通过两次4倍频实现了L波段16倍频,最终成功研制出性能优良的L波段16倍频器,输出功率10.67 dBm,杂波抑制>75 dB,谐波抑制>60 dB,电流仅为120 mA,频谱纯净度较好,温度稳定性较高,能够有效实现倍频功能,满足微波频率源系统的使用要求。     

Improving the Characteristics of integrated EMI filters by embedded conductive Layers

Discrete electromagnetic interference (EMI) filters have been used for power electronics converters to attenuate switching noise and meet EMI standards for many years. Because of the unavoidable structural parasitic parameters of the discrete filter components, such as equivalent parallel capacitance (EPC) of inductors and equivalent series inductance (ESL) of capacitors, the effective frequency range of the discrete filter is normally limited. Aiming at improving high frequency performance and reducing size and profile, the integrated EMI filter structure has been proposed based on advanced integration and packaging technologies , . Some improvements have been made but further progress is limited by EPCs of the filter inductors, which is restricted by dimension, size and physical structure. In this paper, a new structural winding capacitance cancellation method for inductors is proposed. Other than trying to reduce EPCs, a conductive ground layer is embedded in the planar inductor windings and the structural capacitance between the inductor winding and this embedded layer is utilized to cancel the parasitic winding capacitance. In order to obtain the best cancellation effect, the structural winding capacitance model of the planar spiral winding structure is given and the equivalent circuit is derived. The design methodology of the layout and area of the embedded ground layer is presented. Applying this method, an improved integrated EMI filter is designed and constructed. The experimental results show that the embedded conductive layer can effectively cancel the parasitic winding capacitance, hence ideal inductor characteristics can be obtained. With the help of this embedded conductive layer, the improved EMI filter has much smaller volume and profile and much better characteristics over a wide frequency range, compared to the former integrated EMI filter and the discrete EMI filter.     

电容加载对频率选择表面传输特性的影响

有源频率选择表面,是指在频率选择表面中加入变容二极管或PIN二极管等有源器件构成的FSS结构,通过有源器件的可调性来实现对FSS性能的控制。文中根据有源器件的电容等效原理,设计了一种方形缝隙FSS结构,研究了电容加载对FSS传输特性的影响。仿真结果表明,加载电容后其谐振频点向低频偏移,带宽减小,且加载电容对FSS传输特性有较好的可控性。     

中国微米纳米学会－微型压电振动发电机谐振频率调节技术的研究

具有高能量密度的微型压电振动发电机可以无限、持续地为无线传感器网络提供能量。为了适应环境振源频率的变化,提高压电振动发电机的能量转换效率,采用理论建模和数值分析的方法,研究了旁路电容调节振动发电机固有频率的关键技术。建立压电电容与压电层杨氏模量的力学模型,分析压电电容对压电发电机固有频率的影响规律,提出了单晶片和双晶片压电梁的电容频率调节配置方案;分别研究厚度比、长度和宽度对开路、闭路刚度比及固有频率比的影响特性,对结构参数进行了优化配置。     

Role of supply voltage and load capacitors in the experimental operation of small-signal MOSFET amplifiers

Experimental investigation has been performed of the role of supply voltage and load capacitors in small-signal MOSFET amplifier circuit. Particular emphasis has been given to addressing basic issues involving MOSFET amplifiers, rather than modifying the design, and hence standard amplifiers have been considered as the topic of study. The study uncovers that while keeping all other circuit parameters constant, the dc bias voltage (V_DD) plays an important role in creating large voltage gain as it sets the condition for the transistor to be in the saturation mode. This is the region of operation of the transistor where linear amplification is achieved.

The influence of load capacitor C_L has been studied by connecting the output of MOS amplifier to a load. The input impedance of the load circuit is the combination of a capacitance in parallel with a resistance. It is found that the load capacitance is important for determining the frequency range for a constant amplifier gain. In general, the lower the load capacitance, the wider is the midband frequency range. At the high frequency end of the spectrum, the gain drops under the influence of C_L, which is consistent with the PSpice simulation results for small-signal amplifiers. At low frequency end of the spectrum, the midband gain decreases because coupling capacitors and bypass capacitors do not act as perfect short circuits.     

电感、电容在有线电视传输系统中的应用

介绍电感、电容、串联电路、并联电路的特点 ,分析电感、电容对高频率的电视载波信号和低频率的交流信号所呈现的特性 ,对两信号的分离与合成进行阐述 ,介绍如何利用串联谐振和并联谐振回路对信号进行特殊处理     

Parametric resonance in an oscillating circuit utilising nonlinear capacitance

The letter deals with parametric resonance in an oscillating circuit with nonlinear capacitance. Using the method in Reference 3, one can comparatively simply obtain the amplitude/frequency characteristic of the parametric resonance, the dependence of the minimal amplitude needed for excitation of the circuit on the distuning and the phase characteristic of the parametric oscillator.     

Simplified equivalent circuit for a piezoelectric resonator with high electromechanical coupling

A simplified equivalent circuit, which has been used for a resonator with low electromechanical coupling is still a good approximation for a high coupling resonator, provided that the parallel capacitance is so chosen that the circuit yields the exact antiresonance frequency. All the circuit constants can be experimentally determined.     

A Monolithically Integrated 12V/5V Switch-Capacitor DC-DC Converter

A monolithically integrated 12V/SV switch capacitor DC-DC converter with structure-simplified main circuit and control circuit is presented. Its topological circuit and basic operating principle are discussed in detail. It is shown that elevated operating frequency, increased capacitance and reduced turn-on voltage of the diodes can make the converter's output characteristics improved. Reducing resistance of the equivalent resistors and other parasitic parameters can make the operation frequency higher. As a feasible efficient method to fabricate monolithically integrated converter with high frequency and high output power, several basic circuits are parallelly combined where the serial-parallel capacitance is optimized for the maximum output power. The device selection and its fabrication method are presented. A feasible integration process and its corresponding layout are designed. All active devices including switching transistors and diodes are integrated together with all passive cells including capacitors and resistor on a single chip based on BiMOS process,as has been verified to be correct and practical by simulation and chip test.     

一种采用电容共用技术的DC-DC开关电源软启动电路

开关电源DC-DC转换器已经在各种电子设备中取得了广泛的应用。软启动电路保证了DC-DC转换器的正常启动,防止了器件的损坏。从理论上分析了软启动电路原理,设计了一种新型的开关电源软启动电路,该电路引入了电容共用方法,通过与频率补偿电容共用节省了软启动电容,降低了应用成本。并给出了具体电路实现,Spectre仿真结果验证了这种电路的可行性。     

石英音叉陀螺等效参数的测量与分析

分析了石英音叉陀螺连接电路中采样电阻的等效电容(电容特性)对测试的影响,求出了陀螺等效参数,找出了理想工作点.根据陀螺连接电路,针对考虑和不考虑采样电阻的等效电容两种情况进行建模,利用基于初等反射阵(Householder矩阵)变换的最小二乘法求出陀螺两组等效参数,通过仿真对比说明了采样电阻的等效电阻对测试结果有影响,测试中必须考虑.通过求得的参数进行仿真研究,说明了陀螺的真实串联谐振频点为陀螺的理想工作点.