A silicon medium-power transistor for high-current high-speed switching applications

A diffused base, diffused emitter, n-p-n silicon switching transistor has been developed for high-current applications such as switching magnetic memories. The transistor is designed to operate as a switch at the 0.75- ampere level. For a collector current of 0.75 ampere, the large signal current gain is 20 and the saturation voltage drop 4 volts. The breakdown voltages are 75 volts collector-to-base, and 6 volts emitter-to-base. The unit shows fast switching characteristics. The rise, storage, and fall times are each of the order of 0.1 µsec. It has a common emitter unity gain frequency greater than 50 Mc. The transistor employs a localized emitter produced by photoresist techniques and oxide masked diffusion. Lead attachment is accomplished by compression bonding. The silicon wafer is bonded through a molybdenum intermediary to a massive copper stud. The design theory of the device, and the variation of device characteristics with temperature are given. The applicability of this devices to RF amplifier service is also discussed.     

A 2-ns 16K bipolar ECL RAM with reduced word-line voltage swing

A reduced word-line voltage swing (RWS) circuit configuration that results in a high-speed bipolar ECL (emitter coupled logic) RAM is proposed. The write operation can be performed with the configuration in the condition of reduced word-line voltage swing, which causes write operation error in conventional circuit configurations. The proposed configuration cuts off the hold current of the selected memory cell, and then the low-voltage node is charged up through the load p-n-p transistor. A 16-kb ECL RAM with a p-n-p loaded memory cell was fabricated by advanced silicide-base transistor (ASBT) process technology. A 2-ns access time was obtained with 1.8-W power consumption in which the word-line voltage swing was reduced by 0.7 V from a conventional case. Simulation results show that the access time is improved by 25% compared with a conventional case. Simulation results also show that writing time becomes comparable with the conventional time of 1.7 ns when the load p-n-p transistor has a saturation current of 5.0× 10¹⁷ A and a current gain of 1.0. The saturation current is 5 times larger and the current gain is 5 times smaller than those of the standard lateral p-n-p transistor     

Realization of an n-channel GaAs/AlGaAs bistable transistor(BISFET)

The first realization of a novel heterostructure device, the bistable field-effect transistor (BISFET), is reported. The device uses an n-channel GaAs/AlGaAs inversion channel structure. It contains a positive feedback loop between the gate and source terminals, which is activated above a gate voltage of 1.7 V. This leads to abrupt transitions between high- and low-current states as the drain voltage is changed, with a switching ratio of 1.5. The transitions are accompanied by sharp changes in gate current as the feedback loop turns on and off. These transitions, referred to as switch up and switch down, form a large hysteresis loop in the drain characteristics. Hysteresis as large as 3.7 V is observed, making the device strongly bistable     

基于功率晶体管窄脉冲激光驱动设计

激光的高功率、窄脉冲是提高激光引信系统精度,提高引信抗干扰能力的重要手段。为实现小体积的高频、高功率、窄脉冲激光发射,采用大功率晶体管正反馈设计出晶闸管开关应用于高频脉冲激光测距窄脉冲激光发射电路,用钳位二极管抑制激光器反向击穿。通过对RLC充放电回路、晶体管开关电路、晶闸管器件的分析,设计SCR电路,分析放电回路的三个步骤,运用pspice仿真程序对驱动电路进行了参数仿真。制作了印刷电路板,得到峰值电流12 A,脉宽8 ns的脉冲电流。     

A unified approach to characterization of PWM and quasi-PWMswitching converters: topological constraints, classification, andsynthesis

Topological constraints are obtained for pulse width-modulation (PWM) (under both continuous and discontinuous current modes) and quasi-PWM (including families of quasi-resonant and quasi-square wave) converters by identifying their three structures. Switching sequences of these converters and a classification of quasi-PWM power converters are presented. A dual circuit of an ideal diode and an ideal switch are proposed and used to obtain duals of the switching converters in one step. A procedure for the synthesis of quasi-PWM converters is presented     

Accumulation effects in an amorphous chalcogenide thin-film switch

A Te-As-Si-Ge thin-film switch has been investigated by pulse program measurements. Switching occurs after a certain delay time, during which the energy necessary for switching is accumulated. Increasing the pressure applied to the devices leads to a decrease of the switching energy. After removal of the voltage, the device will return to the low-conduction state after a recovery time. Two effects are detected: one enables and the other disables the following pulses, if a first pulse with switching has occurred. A current density of 10⁸A/cm²in the high-conduction state probably leads to liquidification of the conduction channel. The device operates more than 10¹⁰times without any failure. The diode construction is described.     

High-speed low-power direct-coupled complementary push-pull ECLcircuit

This paper presents a high-speed low-power direct-coupled complementary push-pull ECL (DC-PP-ECL) circuit. The circuit features a direct-coupled pnp pull-up and npn pull-down scheme with no extra biasing circuit for the push- and pull-transistor. The bias of the pull-up pnp transistor is established entirely by direct tapping of the existing voltage levels in the current switch. The scheme provides a sharp self-terminating dynamic current pulse through the pull-up pnp transistor during the switching transient, thus completely decoupling the collector load resistor from the delay path. Based on a 0.8-μm double-poly self-aligned complementary bipolar process, the circuit offers 2.0X (2.2X) improvement in the loaded delay at 1.0 (0.5) mW/gate and 2.2X improvement in the load driving capability at 1.0 mW/gate compared with the conventional ECL circuit     

Equivalent circuit models for resonant and PWM switches

The nonlinear switching mechanism in pulsewidth-modulated (PWM) and quasi-resonant converters is that of a three-terminal switching device which consists only of an active and a passive switch. An equivalent circuit model of this switching device describing the perturbations in the average terminal voltages and current is obtained. Through the use of this circuit model the analysis of pulsewidth modulated and quasiresonant converters becomes analogous to transistor circuit analysis where the transistor is replaced by its equivalent circuit model. The conversion ratio characteristics of various resonant converters and their relationship to a single function, called the quasi-resonant function, is easily obtained using the circuit model for the three-terminal switching device. The small-signal response of quasi-resonant converters to perturbations in the switching frequency and input voltage is determined by replacing the three-terminal switching device by its small-signal equivalent circuit model     

A switching lateral transistor

A switching phenomenon has been reported in certain lateral geometry transistors in silicon integrated circuits. These devices switch between conducting and nonconducting states at a critical value of VCE. A hypothesis for the mechanism has been proposed. In this paper an equivalent circuit is developed for the switching lateral transistor and is used to predict transistor behavior. The effect of manufacturing tolerances on the device switching voltage is investigated and a technique of production control is proposed. Circuits using the device are described in which the circuit switching voltage may be varied over a wide range. Some applications of the switching lateral transistor, as an overvoltage protection circuit and a relaxation oscillator, are described.     

基于开关选通控制网络的FED驱动电路设计

基于开关控制技术提出了一种开关选通电流型FED驱动电路。该驱动电路包括FET开关选通电路、数字视频锁存电路及PWM调制转换电路等部分,开关选通电路每8路构成一组,各组同步工作,既减少了电流源数量又保证了PWM脉冲有较大的占空比,PWM信号最大脉宽可达TH/8。采用本驱动电路使得在一行内只有1/8的像素数同时导通,有效降低了行扫描驱动电路的输出电流和功耗,同时相邻阴极依次导通减弱了极间电容影响,有利于改善PWM调制性能。     

Amorphous—Crystalline heterojunction transistors

The characteristics of a new hybrid amorphous-crystalline three-terminal device are described in detail. The device uses a threshold-switching-type chalcogenide glass as the emitter, with a p-type crystalline-silicon base and an n-type silicon collector. When the amorphous emitter is in the off state, the small-signal current gain is significantly smaller than unity. However, once the voltage across the glass is sufficient to produce the on state, the device operates as a transistor with gains well in excess of unity. (Small-signal gains of up to 15 have already been observed in unoptimized configurations.) Under certain conditions, the high-gain on state can be preserved after the switching pulse is removed, suggesting memory-type applications. Previous results on amorphous-crystalline heterojunctions are used to construct a band model for the transistor. This model is used to analyze the steady-state and pulsed-mode characteristics of the device. Recent studies of the on-state current density and carrier concentration are used to calculate the expected gain as a function of current and base doping concentration, with results in good agreement with the experimental data. The behavior of the devices provides another confirmation of the electronic nature of threshold switching in chalcogenide glasses.     

A New Bidirectional Switch With Regenerative Snubber to Realize a Simple Series Connection for Matrix Converters

A new bidirectional switch and snubber circuit are proposed for medium-voltage AC/AC converters. The proposed switch can be constructed using 2-in-1 insulated-gate bipolar transistor and 2-in-1 diode modules, and can reduce the voltage stress of the switching device by series connection. The proposed snubber configuration is very simple and can regenerate absorbed energy. On the other hand, timing errors in the switching between the series-connected switches cause a voltage imbalance in the snubber circuit. Therefore, a simple method is proposed for reducing the voltage imbalance that uses one voltage sensor for each switch circuit. This proposed method controls the snubber voltages by adjusting the switch timings. Furthermore, application of the proposed switch circuit to a matrix converter is discussed and is confirmed by experiment.     

A high voltage MOS switch

A novel MOS high voltage switch suitable for use in integrated circuits is described. The device doubles the operational voltage capability, compared to the standard MOS transistor used in integrated circuits. It uses a unique variable positive feedback which increases dramatically its saturation current and permits significant saving of the circuit area. The switch is fabricated using common Sigate technology. No additional processing steps are required.     

Two-dimensional nonisothermal carrier flow in a transistor structure under reactive circuit conditions

The current density and temperature distribution in a bi-polar power transistor operating in the switching mode under transient conditions has been computed as a function of circuit environment. A modeling was done of the turnoff of the transistor in a circuit containing resistive and inductive elements. Of particular interest was the study of the local current and temperature distribution achieved in the transistor during turnoff in a circuit with a large inductance; in the process of shutoff this inductance maintains the transistor collector current at a high value as the collector junction undergoes avalanche multiplication due to the high voltage induced across this junction by the inductive load. The length of time that the transistor remains in the high-current high-voltage mode during the turnoff transient determines the extent of current crowding and local heating in the device. The method of computation was to solve numerically the electrical carrier flow as well as Poisson's and the heat-flow equations in a two-dimensional model of an n⁺-p-n-n⁺transistor structure, as a function of time. The electrical boundary conditions on the emitter, base, and collector contacts were determined by considering the transistors interaction with its electric circuit environment. This interaction was calculated at each step in time, in an iterative fashion, as the transistor was turned off by extracting current from its base lead. The study permits the evaluation of a given bipolar transistor design with respect to current crowding, heating, and impact ionization in switching circuits containing inductive loads.     

An improved zero-voltage and zero-current-switching full-bridge PWMconverter using a simple resonant circuit

An improved zero-voltage and zero-current-witching full-bridge pulsewidth modulation (ZVZCS-FB-PWM) DC-to-DC converter is presented and analyzed. An auxiliary resonant circuit, which consists of a switch and a capacitor, are added to provide zero-current switching (ZCS) conditions to the primary lagging-leg switches. Due to the auxiliary circuit, when the primary current is being extinguished, the voltage applied on the leakage inductance of the transformer is larger than DC-link voltage. This large voltage increases the maximal output current that can be handled in ZCS. Furthermore, the auxiliary switch softly turns on and turns off     

Ring oscillator circuit simulation with physical model for GaAs/GaAlAs heterojunction bipolar transistors

Switching performance is simulated for GaAs/GaAlAs heterojunction bipolar transistors (HBT's) by combining a realistic physical device model that involves numerical solutions for carrier transport equations and Poisson's equation with our own circuit simulator that enables direct access to the device model embedded in arbitrary circuits. Based on simulated results for five-stage ring oscillators, discussion is given as to how the switching performance depends on the circuit configuration such as current mode logic (CML) without and with emitter follower, and direct-coupled transistor logic (DCTL), inclusion or exclusion of external base areas, and choice for single-or double-heterojunction transistors.     

SiC光控异质结达林顿晶体管的导通机理

利用窄能隙SiCGe三元合金，采用SiCGe/SiC pn异质结产生基极光电流方法，提出了新型SiC光控达林顿异质结晶体管功率开关结构，并用二维数值模拟软件对其导通机理进行了研究. 分析结果表明，SiC光控异质结达林顿晶体管在近红外区内具有明显光控开关特性，其饱和导通压降为4.5V左右，且宜于强光工作.     

A traveling-wave high electron mobility transistor

A traveling-wave high electron mobility transistor (THEMT) is proposed. The device is unique in that it includes an integral distributed load resistor and uses a HEMT as the active device. A rigorous analysis of the device is carried out, using a small-signal equivalent circuit model for an incremental section of the device. Losses and reflected waves are not neglected, as has been done in other work. Treating the device as a four-port network, closed-form expressions for S-parameters are derived. Theoretical calculations, using equivalent circuit parameter values for a HEMT reported in the literature, show that the proposed device is capable of exponential increase in gain with device width. Power gain of more than 10 dB at 50 GHz and remarkably flat response in the frequency range 10-100 GHz are shown to be achievable for a 1-mm-wide device