共查询到20条相似文献,搜索用时 15 毫秒
1.
Acikel B. Taylor T.R. Hansen P.J. Speck J.S. York R.A. 《Microwave and Wireless Components Letters, IEEE》2002,12(7):237-239
In this paper, a new device topology has been proposed to implement parallel plate capacitors using BaxSr1-xTiO3 (BST) thin films. The device layout utilizes a single parallel capacitor and minimizes conductor losses in the base electrode. The new design simplifies the monolithic process and overcomes the problems associated with electrode patterning. An X-band 180° phase shifter has been implemented using the new device design. The circuit provided 240° phase shift with an insertion loss of only 3 dB at 10 GHz at room temperature. We have shown a figure of merit 93°/dB at 6.3 GHz and 87°/dB at 8.5 GHz. To our knowledge, these are the best figure of merit results reported in the literature for distributed phase shifters implemented using BST films at room temperature 相似文献
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Mahmud A. Kalkur T.S. Jamil A. Cramer N. 《Microwave and Wireless Components Letters, IEEE》2006,16(5):261-263
An active phase shifter circuit implemented with discrete components is reported. The tuning element, a ferroelectric varactor, is a parallel plate capacitor with Ba/sub 0.5/Sr/sub 0.5/TiO/sub 3/ (BST) as the dielectric. The circuit consists of two bipolar junction transistors coupled with a feedback network, which contains the varactor and thus produces a transfer function that can be varied with a control voltage. The active nature of the circuit allows for signal gain, while the BST varactor provides a high-Q tuning element. This represents an improvement over strictly passive phase shifters with ferroelectric elements. Circuit simulation results are presented and compared with measured data from the implemented system. The network, even with markedly nonideal transistors, can provide a true all-pass response over the frequency band of interest (200-1100 MHz). The measurement results demonstrate an analog tunability of about 100/spl deg/ with a gain variation of about 0.6 dB at I GHz when using a BST capacitor with a tunability of 2.75:1. 相似文献
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《Power Electronics, IEEE Transactions on》2009,24(1):221-231
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Metin Yazgi Ali Toker Bal S. Virdee 《Analog Integrated Circuits and Signal Processing》2009,60(3):215-220
This paper presents a new negative resistance (NR) circuit which is designed especially to compensate the losses inherent
in conventional distributed amplifiers (CDA). The consequence of the new NR circuit in the CDA is significant improvement
of bandwidth (~15%) with no degradation in gain. In addition, the simplicity of the NR circuit makes it amenable to MMIC technology
and moreover for broadband applications. 相似文献
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Design and Application for PV Generation System Using a Soft-Switching Boost Converter With SARC 总被引:1,自引:0,他引:1
Park S.-H. Cha G.-R. Jung Y.-C. Won C.-Y. 《Industrial Electronics, IEEE Transactions on》2010,57(2):515-522
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In this work, a complementary metal-oxide semiconductor (CMOS) op amp design using composite cascode stages is reported. The design follows the classic Widlar architecture and is fabricated on a 0.25 μm CMOS process. The measured gain of 117 dB is comparable to that achieved in bipolar designs in this architecture. This design is suited for precision instrumentation applications where high gain, low input offset voltage and small cell size are important. It provides a common-mode input range of ?1 to 0.7 V using±1 V power supplies with a quiescent current of 55 μA. The use of the composite cascode also allows for dominant pole compensation with a single capacitor. A phase margin of 43° is achieved with a 3.5 pF compensation capacitor. The resulting cell size for the core op-amp circuit is approximately 24 × 16 mils, including large common centroid input devices that achieve an input offset voltage in the 1 mV range. 相似文献
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This paper proposes a capacitor placement methodology based on sensitivity linear factors of distribution losses with respect to derivation-connected capacitor compensators. The methodology identifies the best size and location for every capacitor bank to be placed in the distribution network considering technical and economical issues. A compensation action is technically accepted when it reduces losses and improves voltage profiles. In order to reduce the search space of feasible solutions and to use real banks capacities, only commercial bank sizes are considered. To evaluate the different alternatives from the economical viewpoint, the net present value is applied. Two examples with different distribution systems reported in the literature are presented in order to illustrate the proposed methodology application. 相似文献
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《Electron Devices, IEEE Transactions on》1962,9(6):484-491
A particular harmonic generator circuit using an ideal nonlinear capacitor is analyzed and theoretical expressions are obtained for the loss involved in generating a high-order harmonic. The harmonic energy is developed in a load resistor either as an exponentially decaying sine wave or as a pulse. The analysis is valid for harmonics of about the tenth or greater. The results are presented in a graphical form that allows the losses involved to be found easily and it is thus shown that the minimum loss in generating a high-order harmonic by this circuit is about 8.5 db independent of the order of the harmonic. The degree to which a charge storage diode approximates to an ideal nonlinear capacitor is then discussed and some experimental results using such a diode are presented. 相似文献
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电流型PWM DC-DC升压转换器的稳定性分析与实现 总被引:2,自引:0,他引:2
文章先对影响电流型DC-DC升压转换器电路的系统稳定性的因素进行分析,然后在电路设计实现上提出了具体的改进办法:在误差放大器模块增加频率补偿电路来消除放大器反馈环路可能存在的振荡现象:采用斜坡补偿电路来增强反馈电流环路的稳定;为了提高电压反馈环路的稳定性,创新提出在芯片外部增加COMP管脚。内部增加环路补偿电路;输入管脚增加旁路电容以减少噪声;输出管脚增加旁路电容以增强芯片反馈系统的稳定性;通过采取这些措施,保证了芯片电路的的稳定性能,并极大的提高了输出电压的精度,设计取得了很大成功。 相似文献
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A new type of electrolytic capacitor has been developed specifically for high-peak-current applications. Preliminary results of an ongoing research effort to determine the operational characteristics of this new type of electrolytic capacitor are reported. The new electrolytic capacitors, designed for pulse discharge application, were tested in a low-inductance discharge circuit to evaluate the maximum current extractable, internal inductance of the capacitors (equivalent series inductance), internal losses of the capacitor (equivalent series resistance), and the potential lifetimes of the capacitors. The peak currents extracted ranged from 17 kA for the 2000-μF unit to 27 kA for the 6800-μF unit, with pulsewidths ranging from approximately 100 to 280 μs for the 2000- and 6800-μF units, respectively 相似文献
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S. S. Saha B. Majumdar T. Haldar S. K. Biswas 《International Journal of Electronics》2013,100(11):755-768
A fully soft-switched boost-converter using a one auxiliary switch is presented here. It uses the minimum number of components in the auxiliary circuit with minimum current stress of the main switch. Since the resonant capacitor charges only through an inductor and a diode, the circuit conduction losses are minimized. The main and auxiliary insulated gate bipolar transistor (IGBT) switches share a common emitter connection, facilitating direct drive to them. Various operating modes of the converter are presented in detail and analysed. The choice of the resonating capacitor and inductor has been done through an optimization process based on the guiding equations working under different modes. In this optimization process, emphasis has been given on minimum voltage stress on the auxiliary switch for a wide duty cycle range of operation. Based on the design, the principle of operation has been verified with computer simulation. Experimental results from a laboratory prototype with active power factor correction confirms the operation of this converter. 相似文献
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This paper presents a low quiescent current,highly stable low-drop out(LDO) regulator.In order to reduce capacitor value and control frequency response peak,capacitor multipliers are adopted in the compensation circuit with mathematic calculations.The phase margin is adequate when the load current is 0.1 or 150 mA.Fabricated in an XFAB 0.6μm CMOS process,the LDO produces 12.2 mV(0.7%) overshoot voltage while the current changes at 770 mA/100μs with a capacitor load of 10μF. 相似文献
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In this article, the effect of pole–zero placements on settling time has been analysed for a three-stage CMOS operational amplifier (opamp) with nested Miller compensation (NMC) and reversed nested Miller compensation (RNMC) schemes. In this study, optimised balancing of speed and power is done for a three-stage CMOS opamp for a given load condition (on-chip opamp). Optimum values of circuit parameters have been derived for power efficient shifting of poles and zeros. The effect of placement of poles and zeros on dynamic settling error (DSE) is analysed by means of numerical simulation using MATLAB. This analysis will be useful to ascertain the relationship between pole–zero placements and settling time. The study of the effects of compensation elements on pole–zero placements has been done to assist the circuit designers to achieve better performance. Analysis of the effect of capacitive load on pole–zero placements and DSE has been done in this study. A technique has been developed to find out the upper and lower limits of compensation capacitor that allows fast settling with low power. The validity of the analytical work has been checked by simulation using Tanner tool in 0.35-µm CMOS technology. In the case of RNMC scheme, a power dissipation of 60.17?µw and a settling time of 340?ns are achieved; the results obtained are better than the earlier reported design technique. In the case of NMC, the simulation has been done to validate the analytical analysis. 相似文献
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Yamamichi S. Lesaicherre P. Yamaguchi H. Takemura K. Sone S. Yabuta H. Sato K. Tamura T. Nakajima K. Ohnishi S. Tokashiki K. Hayashi Y. Kato Y. Miyasaka Y. Yoshida M. Ono H. 《Electron Devices, IEEE Transactions on》1997,44(7):1076-1083
A Gb-scale DRAM stacked capacitor technology with (Ba,Sr)TiO3 thin films is described, The four-layer RuO2/Ru/TiN/TiSix, storage node configuration allows 500°C processing and fine-patterning down to the 0.20 μm size by electron beam lithography and reactive ion etching. Good insulating (Ba0.4Sr0.6)TiO3 (BST) films with an SiO2 equivalent thickness of 0.65 nm on the electrode sidewalls and leakage current of 1×10-/6 Acm2 at 1 V are obtained by ECR plasma MOCVD without any post-deposition annealing, A lateral step coverage of 50% for BST is observed on the 0.2 μm size storage node pattern, and the BST thickness on the sidewalls is very uniform, thanks to the ECR downflow plasma. Using this stacked capacitor technology, a sufficient cell capacitance of 25 fF for 1 Gb DRAMs can be achieved in a capacitor area of 0.125 μm2 with only the 0.3 μm high-storage electrodes 相似文献
18.
Ivan M. Milosavljević Dušan N. Grujić Đorđe Č. Simić Jelena S. Popović-Božović 《Analog Integrated Circuits and Signal Processing》2014,81(1):253-264
This paper describes a method for the estimation of capacitor process variations in integrated circuits and for the subsequent compensation of such variations through a calibration scheme that exploits a variable capacitor bank. An architecture for the calibration circuit is proposed, and various problems that arise during implementation are discussed. The design consists of an oscillator whose output frequency is inversely proportional to the capacitor value and simple state machine for measurement of capacitor process variations. The design of optimum capacitor bank is described together with the adequate tuning plan. The circuit is fabricated and verified in 130 nm RF CMOS process and can be easily scaled to sub-100-nm technologies. 相似文献
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Seung Eon Moon Han Cheol Ryu Min Hwan Kwak Young Tae Kim Su‐Jae Lee Kwang‐Yong Kang 《ETRI Journal》2005,27(6):677-684
A phased array antenna was fabricated using four‐element ferroelectric phase shifters with a coplanar waveguide (CPW) transmission line structure based on a Ba0.6Sr0.4TiO3(BST)/MgO structure. Epitaxial BST films were deposited on MgO (001) substrates by pulsed laser deposition. To attain the large differential phase shift and small losses for a ferroelectric CPW phase shifter, an impedance‐matching‐part adding technique between the effective transmission line and connecting cable was used. The return loss and insertion loss for this technique‐adapted BST CPW device were improved with respect to those for a normal BST CPW device. For an X‐band phased array antenna system consisting of ferroelectric BST CPW phase shifters, power divider, dc block, patch antenna, and programmed dc power, the steering beam could be tilted by 15° in either direction. 相似文献
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This paper proposes a new automatic compensation network (ACN) for a system‐on‐chip (SoC) transceiver. We built a 5 GHz low noise amplifier (LNA) with an on‐chip ACN using 0.18 µm SiGe technology. This network is extremely useful for today's radio frequency (RF) integrated circuit devices in a complete RF transceiver environment. The network comprises an RF design‐for‐testability (DFT) circuit, capacitor mirror banks, and a digital signal processor. The RF DFT circuit consists of a test amplifier and RF peak detectors. The RF DFT circuit helps the network to provide DC output voltages, which makes the compensation network automatic. The proposed technique utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance, gain, and noise figure using the developed mathematical equations. The ACN automatically adjusts the performance of the 5 GHz LNA with the processor in the SoC transceiver when the LNA goes out of the normal range of operation. The ACN compensates abnormal operation due to unusual thermal variation or unusual process variation. The ACN is simple, inexpensive and suitable for a complete RF transceiver environment. 相似文献