不需要散热器的150W dc/dc变换器

用同步整流设计的PowerQordc/dc变换器效率达90％,其输出电压为3.3v,输出电流30A。它的耗热是用     

Multiple output zero-current switching switched-capacitor bidirectional dc–dc converter

The proposed circuit is a multiple output quasi-resonant (QR) zero-current switching (ZCS) switched-capacitor (SC) converter with a bidirectional power flow control conversion scheme. The principles of the proposed multiple output QR ZCS SC bidirectional dc–dc converter are described using a detailed circuit model for analysis. Simulation and experimental results are carried out to verify the validity and the soft switching performance of the proposed converter. The maximum efficiency achievable is about 94 and 92% for the forward and reverse power flow control schemes, respectively. The output voltage can be regulated by changing the switching frequency for the designed compensated closed-loop controller.     

理解并降低dc/dc开关式转换器的接地噪声

一旦了解了两个主要噪声源,就可以尽量减小它们。dc/dc开关式电源转换器的物理干扰众人皆知,除非系统和电路图都经过了精心设计。这些转换器会对电气地注入多余的电荷,产生虚假的数字信号、翻转的双倍时钟、电磁干扰、模拟电压误差,还可能是有害的高电压。随着这类设计复杂性的增加以及应     

Efficiency investigation of dc–dc converter with passively damped input filter circuit

Passive damping of input filters in dc–dc converter applications has suffered enormous criticism presumably due to high conduction losses in the damping resistors. However, an accurate quantitative assessment of their adverse impact on efficiency is lacking. Similarly, not enough attention has been paid to the severity and extent to which they can effectively deteriorate a converter-efficiency under varying operating conditions. In order to quantify these losses we have performed a generalised power-loss analysis that helps in predicting this harmful effect of damping resistors on overall filter-converter system efficiency. A practical damping approach using a shunt R–C network, which is most commonly suggested in dc–dc converter applications, is investigated theoretically as well as experimentally. Results show that converter efficiency is susceptible to severe degradation, especially at high loads as well as at smaller damping resistor values. Furthermore, it is shown that these losses are considerably higher in buck-type converters than in boost-type converters. Authors emphasise that considering this negative impact on power economy is of crucial importance while optimising such a damping network.     

尺寸为2.2×2.2英寸的dc/dc转换器功率达40W

有高达91％的效率和宽的工作温度范围ExA40仓系列dc/dc。转换器封装在一个2.2*2.2英寸的开放式结构中,提供4OW一10W的功率,超过绝大多数同尺寸设备。该转换器有7种型号,输     

使用简单步进降压dc／dc转换器的三通道白光LED驱动器

只要增加少许元件，就可以用一只高效率的步进降压dc／dc转换器，做出一个恒流的多通道LED驱动器。驱动一只单通道LED相对比较简单，但要驱动多通道并联LED，事情就变得比较复杂了。     

On the output voltage ripple in the ideal boost and buck-boost dc–dc converters

This paper re-examines the typical textbook analysis of the ideal boost and buck-boost dc–dc converters operating in the continuous conduction mode. It is shown that there is a range of valid average load currents for which the simple equation usually derived to relate output voltage ripple to output capacitor size in both converters is not strictly correct. An equation giving the correct relationship for the range of load currents in question is derived, using basic concepts. It is shown that the error introduced by using the original equation where the new one is appropriate is significant if both the switching duty cycle of the converter is relatively small (～0.3 or smaller) and the average load current is close to the continuous conduction cutoff. In such cases the size of the output capacitor needed to meet a maximum output voltage ripple specification will be significantly underestimated. The results are illustrated with an example and PSPICE verification.     

双核时代 HP Compqa dc7600商用台式机

HP一向是IT技术应用的领域头羊，英特尔（Intel）双核CPU Pentium的发布，HP自然也是最快做出反应的厂商——在国内发布的采用英特尔Pentium D双核心处理器技术的HP Compaq dc 7600商用台式机，就是其技术领先的最好例证。     

用dc溅射法制备的Y-Ba-Cu-O膜

用dc二极管溅射制备Y-Ba-Cu-O膜。膜不是淀积在正对靶的基片上。产生这种现象的原因似乎是由于电子轰击活化Ba所造成的。为了制备厚度均匀的膜。在靶和基片极之间采用强的横向磁场是有效的。     

DC/DC变换器性能更好、尺寸更小,这就是最新dc/dc电源的特征

安装于DIN导机之上的dc/dc交换器 ERD系列dc/dc变换器带有卡座,以便安装到DIN导轨上。有30、60和150W三种规格。 输出电压范围从5到48Vdc;输入电压12、24、48Vdc。(价格:30W型,164美元;卡座:27美元——现货)     

高温超导双晶结垫圈型dc SQUID 磁强计的研制

采用脉冲激光沉积法(PLD)在10x10mm2的SrTiO3双晶基片上制备了纯c取向的高温超导YBCO薄膜,薄膜表面平整,杂相颗粒少,在20μm尺度范围内,起伏在几个nm之内。通过标准光刻和离子束刻蚀工艺制备出了高温超导垫圈型双晶结dcSQUID磁强计。测试结果表明:磁强计有效面积达0 09mm2,在没有超导屏蔽的环境下,磁强计白噪声区磁场噪声达到333fT/Hz1/2。     

YBa2Cu3O7−x dc squid magnetometers with bicrystal junctions for biomagnetic multichannel applications

We have fabricated magnetometers based on direct-coupled YBa₂Cu₃O_7−x superconducting quantum interference devices (SQUID) with SQUID inductances of 50 pH and 100 pH on 10×10 mm² 24° SrTiO₃ bicrystal substrates. The thin films were deposited by hollow cathode discharge sputtering and patterned using conventional photolithography and Ar ion beam etching. The optimization of the fabrication process was performed utilizing design of experiment methodology. The SQUID magnetometers were operated with an improved direct-coupled flux-locked loop electronics with a preamplifier voltage noise of 0.44 nV Hz^−1/2 and bias reversal (f_b=0.1–500 kHz). The best sensor had a white noise of 41 fT Hz^−1/2 and a 1/f corner at 2 Hz, including electronics and environmental noise. High-quality magnetocardiograms recorded in the Berlin magnetically shielded room (BMSR) illustrate that the sensors are suitable for biomagnetic multichannel systems.     

A compact 1–30 μH, 1–350 μF, 5–50 mΩ ESR compliant, 1.5% accurate 0.6 μm CMOS differential ΣΔ boost dc–dc converter

Emerging high-end portable electronics demand on-chip integration of high-performance dc–dc power supplies not only to save pin count, printed circuit board (PCB) real estate, and the cost of off-chip components but also to better regulate the point of load (PoL). In the face of a widely variable LC filter, however, integrating the frequency-compensation circuit is difficult without sacrificing stability performance, which is why integrated controller ICs only cater to relatively narrow LC ranges. While ΣΔ control addresses this LC compliance issue in buck dc–dc converters with high equivalent series resistance (ESR) output capacitors, it is not clear how it applies to ΣΔ boost converters. To that end, this paper discusses, analyzes, and experimentally evaluates a prototyped 0.6 μm CMOS differential ΣΔ boost converter. Experimental results verified the switching supply was stable across 1–30 μH, 1–350 μF, and 5–50 mΩ of inductance, capacitance, and ESR while keeping output voltage variations in response to 0.1–0.8 A load and 2.7–4.2 V line changes to less than ±1.5%, peak efficiency at 95%, and switching frequency variation to less than 27%.