A capacitor charging power supply utilizing a Ward converter

A prototype capacitor-charging power supply (CCPS) that utilizes a Ward converter is presented. This converter is a member of the family of resonant converters and is capable of zero-current switching. It is applicable to capacitor charging because of its inherent short-circuit protection and its insensitivity to the value of the load capacitance. The converter is controlled using a constant on-time constant frequency scheme that allows the utilization of zero-current switching techniques. The prototype CCPS is capable of charging various values of load capacitors up to 1000 V DC. Waveforms that show single- and repetitive-charge operation of the CCPS are presented     

Digital power-factor correction for a capacitor-charging power supply

The design and construction of a low-power low-cost power supply capable of charging an energy storage capacitor from a 120-V AC source and capable of power-factor correction (PFC) is presented. The load that is generally connected to a capacitor-charging power supply (CCPS) is a pulsed power load (i.e., laser, cardiac defibrillator, or flash lamp). A flyback converter was incorporated into the CCPS because it is capable of charging a capacitor while maintaining a high power factor. The control system of the CCPS uses peak current control to achieve PFC and is implemented using standard "off-the-shelf" digital logic components. A 300-V prototype has been constructed and tested. The experimental results show that a high power factor is obtained by the CCPS utilizing a flyback converter and the digital logic control system.     

一种实现50 ms断电维持供电的电路设计

针对机载28 V直流供电系统50 ms供电中断的情况,基于钽电容储能作用,采用充电电路、储能电容、放电电路的结构,设计了一种50 ms断电维持供电电路。在输入正常时,由充电电路将钽电容充电至高压来存储能量;当输入断电时,由放电电路将钽电容储能尽可能释放给后级DC-DC变换器,从而实现50 ms不间断供电。分析了电容充电浪涌电流和断电维持电压振荡的问题,提出了充电限流和宽滞回电压欠压保护方案。经实验电路测试验证,满足指标要求。     

串联谐振电容器充电电源特性研究

负载与谐振回路L-C以串联形式输出称为串联谐振变换器,将串联谐振变换器应用到电容器充电技术中,产生了串联谐振电容器充电电源（CCPS）。和普通电容器充电电源相比,串联谐振电容器充电电源具有抗负载短路能力强、体积小、控制简单、可开环控制等优点,在国防科研中得到广泛应用。为了研究串联谐振CCPS电路的工作特性,文章给出了其电路原理图及等效电路,建立了该电路的数学模型。通过数学仿真的方法,给出了谐振电路的特性。实验结果验证了所采用控制方案的正确性和充电系统的有效性。     

直线加速器长脉冲调制电源的理论计算

设计并模拟计算了高能直线加速器长脉冲调制电路,该电路所用的储能电容为30μF,由直流高压电源充电到速调管所需工作电压,在1.5ms,800μs和400μs的放电脉宽内,储能电容的电压降分别为5.59%,3.02% 和1.52%,为使负载得到±0.50%的输出脉冲电压,采用补偿电路来补偿脉冲放电期间储能电容的电压降.本文阐述了这种脉冲调制电路的计算结果.     

A feedback loop regulated bootstrap driver circuit with improved drive capability for high voltage buck DC–DC converter

A novel bootstrap driver circuit applied to high voltage buck DC–DC converter is proposed. The gate driver voltage of the high side switch is regulated by a feedback loop to obtain accurate and stable bootstrapped voltage. The charging current of bootstrap capacitor is provided by the input power of the DC–DC converter directly instead of internal low voltage power source, so larger driver capability of the proposed circuit can be achieved. The bootstrap driver circuit starts to charge the bootstrap capacitor before the switch node SW drop to zero voltage at high-side switch off-time. Thus inadequate bootstrap voltage is avoided. The proposed circuit has been implemented in a high voltage buck DC–DC converter with 0.6 µm 40 V CDMOS process. The experimental results show that the bootstrap driver circuit provides 5 V stable bootstrap voltage with higher drive capability to drive high side switch. The proposed circuit is suitable for high voltage, large current buck DC–DC converter.     

一种高精度高稳定性锯齿波振荡器的设计

设计了一种应用于DC/DC开关电源管理芯片的锯齿波振荡器,该电路利用内部基准电流源产生的电流对电容进行充放电,使得产生的锯齿波信号随电源电压和温度的变化较小,采用迟滞技术提高了锯齿波信号幅值.采用基于CSMC的0.5μmCMOS 工艺进行仿真.结果表明,该电路产生的振荡频率为5MHz,信号幅值为0-3V,电源电压在2....     

36kV/10kW CO2激光器充电电源的研制

为了改善现有CO2激光器工频LC谐振充电时充电电压随激光器工作频率升高而降低、影响激光输出的稳定性和光束质量,不利于装置的小型化和轻量化的问题。采用全桥逆变结构和串联谐振软开关电路,研究了36kV/10kW高频高压充电电源。该电源系统采用三相380V交流电作为供电系统,大功率智能功率模块作为全桥逆变电路。逆变交流信号经串联谐振电路及高频脉冲变压器得到高压脉冲信号,高压脉冲经整流给负载电容充电,电源应用电压电流双闭环控制系统,输出电压、电流经采样及放大后,反馈到电源控制芯片SG3525,芯片SG3525通过判断反馈信号的大小,控制输出脉冲宽度调制驱动信号的占空比。激光器放电频率为25Hz时,电源输出电压为37kV,峰值输出功率为13.05kW,充电效率为0.826。结果表明,该高频高压充电电源适合用作CO2激光器的高压充电电源。     

激光器用快速退压式电光Q开关驱动器的研制

研制了一种快速退压式电光Q开关驱动器,它具有结构简单、稳定性好、体积小且成本低的优点。由基于PWM型集成控制器SG3525的升压型DC/DC开关电源提供0V至1500V的高压直流电平,稳定度在0.2%以内,纹波小于300mV;采用高压功率场效应管作为开关器件,获得了频率在1KHz至50KHz、高电平在0V至1200V可调、下降沿可达6ns的高压负脉冲;采用LiNbO3晶体作为电光晶体,运用于小功率Nd：YVO4激光器的电光调Q,工作在高电平为725V,频率为10KHz时,获得了脉宽约13ns的脉冲激光输出。     

A high-voltage modulator for high-power RF source research

The design, construction, and operating results of a high-voltage modulator system capable of generating 700-kV, 2.5-μs pulses at 5 p.p.s. into a load of 900 Ω are presented. The modular is used to energize a variety of high power microwave devices requiring voltage stability and reproducibility. Voltage ripple is less than 0.2% during the 1.0-μs flat top, with a shot-to-shot voltage variation of less than 0.1%. The primary circuit consists of two seven-stage tunable Rayleigh-type pulse-forming networks (PFNs) connected in parallel with a total impedance of 2.25 Ω, a total capacitance of 0.56 μF, and a total inductance of 2.8 μH. The PFN is charged by a highly stable 80-kV capacitor charging power supply (0.1% RMS voltage ripple) at a rate of 10 KJ/s. The total energy stored (1.5 kJ) is released through an ITT F-187 thyratron into a 20:1 pulse transformer, which generates 700-kV, 2.5-μs pulses. By changing the transformer, it was possible to obtain 250-kV, 1.70-kA pulses for driving low-impedance relativistic magnetron diodes. The flat-top voltage generated by the modulator is highly desirable for driving RF sources requiring high-quality electron beams, such as free-electron lasers (FELs) and cyclotron autoresonance masers (CARMs). The modulator performance in the relativistic magnetron and CARM experiments is described     

Control algorithms and circuit designs for optimal flyback-chargingof an energy-storage capacitor (e.g., for flash lamp or defibrillator)

A flyback-type of a transformer-coupled DC/DC power converter supplies a train of current pulses to charge an energy-storage capacitor to a desired high voltage, converting input DC power obtained from a lower voltage DC source. The energy-storage capacitor is charged to a specified voltage within a specified time with minimum peak and RMS currents in the transistor, the rectifier diode, the transformer windings and the DC power source, minimizing the i²R losses. This is done by generating: (1) energy-storage current pulses in the power transistor and the transformer primary winding in which the current increment from the beginning to the end of a pulse is only a small fraction of the final (peak) value; and (2) energy-delivery flyback current pulses in the capacitor and the transformer secondary winding in which the current decrement from the beginning to the end of a pulse is only a small fraction of the initial (peak) value. Recommended methods are: (1) hysteretic current-mode control with current sensing in both transformer windings; (2) peak-current-commanding current-mode control with switching frequency or transistor-nonconducting time varying in a prescribed way during the charging; or (3) valley-current-commanding current-mode control with switching frequency or transistor-conducting time varying in a prescribed way during the charging. Compared with one nonoptimal method, peak currents are reduced by a factor of about 2 and i²R power losses are reduced by a factor of about 1.33     

A 10 b, 20 Msample/s, 35 mW pipeline A/D converter

This paper describes a 10 b, 20 Msample/s pipeline A/D converter implemented in 1.2 μm CMOS technology which achieves a power dissipation of 35 mW at full speed operation. Circuit techniques used to achieve this level of power dissipation include digital correction to allow the use of dynamic comparators, and optimum scaling of capacitor values through the pipeline. Also, to be compatible with low voltage mixed-signal system environments, a switched capacitor (SC) circuit in each pipeline stage is implemented and operated at 3.3 V with a new high-speed, low-voltage operational amplifier and charge pump circuits. Measured performance includes 0.6 LSB of INL, 59.1 dB of SNDR (Signal-to-Noise-plus-Distortion-Ratio) for 100 kHz input at 20 Msample/s. At Nyquist sampling (10 MHz input) SNDR is 55.0 dB. Differential input range is ±1 V, and measured input referred RMS noise is 220 μV. The power dissipation at 1 MS/s is below 3 mW with 58 dB of SNDR     

采用串联结构的高压电容恒流充电电源

在电压大范围变化条件下,针对纯电容负载介绍了串联负载谐振电路的工作原理、恒流特性以及软开关工作方式对高压电容充电品质的影响.在高频高压情况下,分析了以低压方式解决高压问题的多模块串联均压的典型电路结构,并讨论了变压器分布电容和漏感对充电的影响.实现了由直流48V供电,输出为10kV的高压电容恒流充电\电源.     

Design and Power Optimization of High-Speed Pipeline ADC for Wideband CDMA Applications

This paper presents a 7-bit 64 MS/s pipeline A/D convertersuitable for wideband CDMA applications. Targeting atachieving low power dissipation at high speed, techniques suchas digital correction and optimal scaling of capacitor valuehave been employed. Switched-Opamp technique is used tofurther reduce power consumption. This ADC is implemented in0.5 m standard CMOS process. It operates from a single 3 V supply, and dissipates only 31 mW at 64 MS/s.     

一种基于复合运放的线性锂离子电池充电器

基于复合运放,设计了一款新颖的线性锂离子电池充电器.该充电器根据锂离子电池充电的特性,采用三阶段充电法,即涓流充电(预处理),恒流充电(快充),恒压充电(充满).仿真结果显示,在4.5 V电源电压下,充电器实现了涓流充电电流80 mA,恒流充电电流800 mA,及恒定电压4.2 V的充电过程.另外,设计中利用充电功率管的栅极寄生电容作为充电环路的补偿电容,节省了芯片成本和面积.     

A 10 bit 20 MS/s 3 V supply CMOS A/D converter

A 10 bit CMOS A/D converter with 3 V power supply has been developed for being integrated into system VLSI's. In this A/D converter, redundant binary encoders named “twin encoders” enhance tolerance to substrate noise, together with employing differential amplifiers in comparators. The bias circuit using a replica of the amplifier is developed for biasing differential comparators with 3 V power supply. Subranging architecture along with a multilevel tree decoding structure improves dynamic performance of the ADC at 3 V power supply. The A/D converter is fabricated in double-polysilicon, double-metal, 0.8 μm CMOS technology. The experimental results show that the ADC operates at 20 MS/s and the twin encoders suppress the influence of substrate noise effectively. This ADC has a single power supply of 3 V, and dissipates 135 mW at 20 MS/s operation     

Low power data decision IC for 20-40 Gbit/s data links using 0.2μm AlGaAs/GaAs HEMTs

A decision IC for optical data links at bit rates of 20-40 Gbit/s has been realised by using 0.2 μm AlGaAs/GaAs HEMT technology and tested on-wafer at bit rates up to 25 Gbit/s. The IC can be operated with a supply from ~3.3 to 5.2 V and a DC current of ~50 mA     

A compact low noise operational amplifier for a 1.2 μm digitalCMOS technology

A compact low noise operational amplifier using lateral p-n-p bipolar transistors in the input stage has been fabricated in a standard 1.2 μm digital n-well CMOS process. Like their n-p-n counterparts in p-well processes, these lateral p-n-p transistors exhibit low 1/f noise and good lateral β. The fabricated op amp has an area of only 0.211 mm² with E_n=3.2 nV/√(Hz), I_n=0.73 pA/√(Hz), E_n and I_n 1/f noise corner frequencies less than 100 Hz, a -3 dB bandwidth greater than 10 MHz with a closed loop gain of 20.8 dB, a minimum PSRR (DC) of 68 dB, a CMRR (DC) of 100 dB, a minimum output slew rate of 39 V/μs, and a quiescent current of 2.1 mA at supply voltages of ±2.5 V. The operational amplifier drives a 1 kΩ resistive load to 1 V peak-to-peak at 10 MHz and has been used as a versatile building block for mixed-signal IC designs     

多功能太阳能移动电源的研制

在户外,为解决数码产品续航,待机问题,设计一款多功能太阳能移动电源,使用典型芯片和常用元件设计控制电路,将太阳能充电和手摇充电合为一体。单晶硅太阳能PV板将光能转换为电能,经直一直流变换电路,在标准USB口输出DC5V,实现太阳能充电。手摇发电机将机械能转换为电能,经交一直流变换电路后稳压输出,实现手摇充电。选用LM2575代替传统三端集成稳压芯片设计稳压电路,经过电路调试和实验,太阳能和手摇模块均可供手机及其他5V数码产品充电,充电可靠,成本低,体积小,另外增加照明和电量指示等辅助功能,更加实用。     

GaAs switched capacitor DC-to-DC converter

A switched capacitor DC-to-DC negative converter fabricated in GaAs MESFET technology is introduced in this paper. The converter has an oscillator that runs at 250 kHz, and requires two external capacitors, 0.1 and 1 μF. The converter runs off a wide range of supply voltage, 2 to 10 V, and has a typical output impedance of 75 Ω. A typical open circuit voltage conversion efficiency of 99.6% is achieved. The circuit can be integrated with other GaAs circuits to provide an on-chip negative supply. Measured, simulated and analytical results are introduced in this paper