Controlled turn-on thyristors

In a one or more amplified stage thyristor design it is possible to control the peak current level of all but the final stage with impedance built into the p-base zone. This impedance reduces both the current and the duty cycle of the protected amplifying stage effectively protecting it from undesirable temperature rises during turn-on. A further bonus and perhaps equally important is the fact that the amplifying stage and its current control impedance can be used to reduce and essentially fix the voltage level at which the following stage turns on. This results in a lower voltage, lower stress turn-on of the following stage, and a device essentially protected from di/dt turn-on failure. This paper describes several aspects of controlled turn-on in the context of a 2.6- and 6-kV light triggered thyristor. In particular we discuss selection of the resistor value, the problem of unwanted current control resistor modulation by device current as well as some factors affecting the proper wattage of such resistors. We also discuss the role current control resistors can play in controlling avalanche current from known locations on the device.     

Pulse current trimming of polysilicon resistors

The practical application of pulse current trimming of polysilicon resistors has been investigated and successfully implemented in large scale integrated circuit production. In-package pulse current trimming of heavily doped polysilicon resistors allows precise control of the final resistor value and can effectively compensate for process variation in polysilicon sheet resistance. The technique requires no additional process complexity, is layout efficient, remarkably accurate, and is quick and inexpensive from a test perspective. Resistance reduction occurring during the trim process is shown to be reversible to a small, but usable, extent for n-type polysilicon. Thermal modeling of the resistor trim process shows that the peak temperature reached within the polysilicon film must exceed the highest temperature encountered during wafer fabrication before any permanent resistance change occurs. As the resistor is further trimmed, the film temperature approaches the melting point of silicon     

一种电感值可独立调节的低噪声有源电感

基于回转器-电容原理,联合采用回转电容、可调反馈电阻、补偿电容和噪声抵消支路,提出了一种电感值相对于Q值可独立调节的低噪声有源电感。通过改变正-负跨导器之间的回转电容值来实现电感值的调节。因调节电感值而引起的Q值变化,可通过调节正-负跨导器之间的可调反馈电阻值和伪差分对之间的补偿电容值来共同补偿,从而实现电感值相对于Q值的独立调节。通过噪声抵消支路来降低有源电感的噪声。对该有源电感的性能验证表明,协同调节3个外部偏置电压,可实现电感值相对于Q值的独立调节,在电感峰值变化幅度为175.49%时,Q值的峰值变化幅度仅为4.88%。在0~6 GHz内,有源电感的输入参考噪声电流均小于45 pA·Hz-1/2,噪声较低。     

High frequency saturated CMOS floating resistor for fully-differential analogue signal processors

A floating resistor on a current source technique is introduced. All the transistors are saturated leading to higher frequency response than previously proposed techniques. Simulated results, using HSPICE level 3, for a 214 k Omega floating resistor have shown a -3 dB frequency of the order of 1 GHz. Its total harmonic distortion at 10.7 MHz and including 2% worst case transistor mismatches is less than -62 dB for fully differential applied signals up to 2 V peak to peak.<>     

一种连续可调接地电容倍比器的实现

提出了一种用电流传送器 (CC +/-)构成的接地电容倍比器。该倍比器的电容量可经接地电阻连续调节 ,线性可调范围大 ,利用此接地电容 ,另添加一个电阻 ,可构成一阶低通滤波器 ,改变接地电阻的大小 ,即改变了滤波器的 -3 d B截止频率 ,计算机仿真结果与理论分析相吻合     

On the temperature behavior of the logarithmic integrated circuit current source

The logarithmic constant current source in silicon integrated circuit form has been analyzed in detail. It is shown that the temperature behavior is critically dependent on the voltage developed across the emitter resistor of the source transistor. This resistor value can be chosen so as to over, under, or perfectly temperature compensate the current source. The results are used to design a current source and are verified by computer simulation.     

A hybrid active filter for damping of harmonic resonance inindustrial power systems

This paper proposes a hybrid active filter for the damping of harmonic resonance in industrial power systems. The hybrid filter consists of a small-rated active filter and a 5th-tuned passive filter. The active filter is characterized by detecting the 5th-harmonic current flowing into the passive filter. It is controlled in such a way as to behave as a negative or positive resistor by adjusting a feedback gain from a negative to positive value, and vice versa. The negative resistor presented by the active filter cancels a positive resistor inherent in the passive filter, so that the hybrid filter acts as an ideal passive filter with infinite quality factor. This significantly improves damping the harmonic resonance, compared with the passive filter used alone. Moreover, the active filter acts as a positive resistor to prevent an excessive harmonic current from flowing into the passive filter. Experimental results obtained from a 20-kW laboratory model verify the viability and effectiveness of the hybrid active filter proposed in this paper     

Thick-film resistor quality indicator based on noise index measurements

A quality indicator for thick-film resistors based on noise index and resistance measurements is proposed. As this correlates resistor transport and noise characteristics and has mobility dimensions, we titled it to be noise reduced mobility. The experimental results for thick-film resistors, realized using three different resistor compositions with sheet resistances of 1, 10 and 100 kΩ m/sqr show that layers with sheet resistance of 10 kΩ0.25>m/sqr have minimum value of noise reduced mobility in comparison with layers formed using resistor compositions with sheet resistances of 1 and 100 kΩ m/sqr. The potential and resistance distributions measured along test resistors show that the noise reduced mobility is in correlation with thick-film inhomogeneity.     

ESD对RuO2厚膜电阻阻值的影响

采用静电放电(Electrostatic discharge,ESD)发生器对RuO2厚膜电阻直接放电,研究了电阻阻值变化率与电阻尺寸、阻值和ESD条件的关系。结果表明:厚膜电阻阻值受ESD作用而下降;相同ESD及阻值条件下的阻值变化率随电阻尺寸的增大而减小;相同电阻的阻值变化率随ESD电压的增大而增大;10kΩ左右的厚膜电阻在ESD作用下的阻值变化率最大,阻值变化率随着阻值的减小和增大而呈减小趋势;对10kΩ厚膜电阻反复施加不断增大的ESD电压,除宽度尺寸为0.45mm的电阻阻值在8～10kV之间出现一次回升外,电阻阻值逐步下降。     

Sub-1-μA dynamic reference voltage generator forbattery-operated DRAMs

A new reference voltage generator with ultralow standby current of less than 1 μA is proposed. The features are: 1) a merged scheme of threshold voltage difference generator and voltage-up converter with current mirror circuits, and 2) intermittent activation technique using self-refresh clock for the DRAM. This combination enables the average current to be reduced to 1/100 and the resistance of trimming resistor to be reduced to 1/10 compared to conventional reference voltage generators, while maintaining high accuracy and high stability. The proposed circuit was experimentally evaluated with a test device fabricated using 0.3-μm process. An initial error of less than 4% for 6 trimming steps of the trimming resistor, temperature dependence of less than 370 ppm/°C from room temperature to 100°C, and output noise of less than 12 mV for 1 V_p-p V_cc bumping are achieved. These results are sufficient for achieving high-density battery operated DRAMs with low active and data-retention currents comparable to SRAMs     

一种低温漂电流感应电路的分析与设计

提出了适用于电流模DC-DC转换器的低温漂高精度的电流感应电路,用MOS管线性电阻和负温度系数电阻一起组合来实现。所设计电路应用于一款DC-DC升压转换器中,并在CSMC0.5μm工艺上进行流片验证,在输入电压1.8V,输出3.6V的条件下,带载能力达到0.8A,不同温度环境下,电感峰值电流限流值维持在2.1A左右,达到了很好的感应效果。     

A novel topology for grounded-to-floating resistor conversion in CMOS technology

A new circuit topology to convert grounded resistors to an equivalent floating resistor is presented and discussed. The value of the resulting floating resistor equals the sum of the two grounded resistors. The new topology can be used to convert either passive, active grounded resistors or active grounded conductances. The new topology is used in the design of a current controlled very high value floating resistor in the range of GΩ. This was achieved by utilising the output conductance of two matched transistors operating in the subthreshold region and biased using a 500 nA current. The practicality of the new topology is demonstrated through the design of a very low frequency bandpass filter for artificial insect vision and pacemaker applications. Simulations results using Level 49 model parameters in HSPICE show an introduced total harmonic distortion of less than 0.25% for a 1 V_pp input signal in a 3.3 V 0.25 μm CMOS technology. Statistical modelling of the new topology is also presented and discussed.     

30 GHz SiGe active inductor with voltage controlled Q

An active inductor (AI) based on a cascade gyrator for 30 GHz applications implemented with a 0.25 μm in SiGe technology is presented. The gyrator converts not only a key capacitor into an inductor, but also an added resistor, into a negative resistor. This gyrator-RC has its losses compensated by the negative resistor improving the active inductor Q factor. Changing the bias voltage and current allows to obtain a variable AI. A study of a cascade gyrator AI topology is done to understand the circuit behavior and key elements. For this purpose, an AI impedance model is introduced and discussed. An improved AI with the added resistor replaced by a voltage controlled mosfet resistor is proposed. This extra control voltage allows the variable AI quality factor fine tuning. Schematic and circuit extracted from layout simulations are presented, and compared with the measured results of two prototypes of the AIs (one with a fixed resistor and other with a voltage controlled resistor). A prototype of a high pass filter using the AI with fine Q control was fabricated. Non-linear simulations for different input signal levels were performed and compared with measurements. Also discussion on the non-linear models accuracy is performed.     

Modeling and simulation of a chaotic oscillator by MATLAB

A MATLAB-based system is presented to model and simulate a chaotic oscillator. Chua’s circuit is selected to describe the chaos phenomenon. Furthermore, the nonlinear resistor (Chua’s diode) is modeled by an I-V piecewise-linear characteristic whose current and voltage ranges can be varied by the user. It is shown how to generate a sequence of chaotic behaviors by varying the value of a linear resistor. The simulation results can be plotted in a 2D and 3D graphs. Finally, it is described the synthesis of the chaotic oscillator by using standard CMOS integrated-circuit technology.     

High resolution AC temperature field imaging

Using a CCD camera and a multichannel lock-in scheme, the authors have enhanced the capabilities of photoreflectance microscopy to obtain a 2D image without scanning the sampler thus dramatically reducing the acquisition time. The photoreflectance images presented show Joule and Peltier heating of a polycrystalline Si 1 kΩ resistor across which a 30 mA peak to peak sinusoidal current is forced     

`R-lens filter': An (RC)n current-mode lowpass filter

A continuous-time (RC)ⁿ lowpass filter is presented that can be fully integrated with cutoff frequency down to the 0.1 MHz range. The circuit is based on a cascade of new compact RC-cells that provides current amplification and filtering with minimum power dissipation (<15 μW/pole) using a single supply voltage (2 V). The high value resistance of the RC-cell is obtained by means of a current conveyor feedback that de-magnifies the signal current flowing in a small physical resistor. The circuit is intrinsically low-noise due to a `cooling effect' in the equivalent resistor     

An Electronically Tunable Linear or Nonlinear MOS Resistor

We present a bidirectional MOS resistor circuit that is electronically tunable and has zero dc offset. For a given I–V characteristic, the circuit senses the source-to-drain potential across an MOS device and automatically generates an appropriate bias for the gate terminal to implement the characteristic via negative feedback. We show that the I–V characteristic of the resistor can be designed to be linear, compressive or expansive by using appropriate translinear current mode circuits for the feedback biasing. Our technique does not require the MOS transistor to operate in the triode region and is valid in both weak and strong inversion. Experimental results from a CMOS process show that a square-root, linear, or square resistor can be implemented as examples of our topology. The linear version was tunable over a resistance range of 1 ${hbox{M}}Omega$ –100 ${hbox{G}}Omega$ in our particular implementation and exhibited proportional-to-absolute temperature (PTAT) behavior. The measured excess noise of the resistor agrees with theoretical predictions.      

一种可调节电流的电流型PWM直流转换器

介绍一种用于驱动发光二极管(LED)的可调节电流的电流型PWM直流转换器.该直流转换器由于接有一个外接电阻,可以通过调节外接电阻的大小来调节输出电流.输出电流调节范围在5～40mA之间.主要分析了电路的输出电流调节功能,和这种输出电流可变的电流型PWM直流转换器的电流和电压反馈环的反馈实现原理.并简要介绍了这种带电流调节功能的PWM直流转换器的工作原理,最后给出了电路在输出不同电流时使用HSPICE软件对反馈参考电压,PWM锁存器输出波形的仿真结果.     

Sub 1-V highly-linear low-power class-AB bulk-driven tunable CMOS transconductor

This paper describes the design and realization of a sub 1-V low power class-AB bulk-driven tunable linear transconductor using a 0.18-μm CMOS technology. The proposed transconductor employs a class-AB bulk-driven differential input voltage follower and a passive resistor to achieve highly linear voltage-to-current conversion. Transconductance tuning is achieved by tuning the differential output current of the core transconductor with gain-adjustable current mirrors. With 10.4-μA current consumption from a 0.8-V single power supply voltage, simulation results show that the proposed transconductor achieves the total harmonic distortion (THD) of <?40 dB for a peak differential input voltage range of 800 mV at frequencies up to 10 kHz. The simulated input-referred noise voltage integrated over 10-kHz bandwidth is 100 μV, resulting to an input signal dynamic range of 75 dB for THD <?40 dB. A biquadratic G_m-C filter is designed to demonstrated the performance of the proposed transconductor. At the nominal 10-kHz cut-off frequency, the filter dissipates 34.4 μW from a 0.8-V supply voltage and it achieves an input signal dynamic range of 67.4 dB for the third-order intermodulation distortion of <?40 dB.