电流检测器MAX4373／74／75

MAX4373、4374及4375是三种由电流检测放大器、比较器及基准电压源组成的微功耗、低价电流检测器IC。MAX4373内部仅有一个比较器,4374及4375内部有两个比较器。工作电压范围从2.7V到28V;工作电流典型值仅50μA;满量程精度0.66%;内部有基准电压源及比较器,可组成过流保护及欠流/过流检测电路(后者仅MAX4374、4375);比较器输出锁存;电流检测放大器有     

一种新颖的电流采样电路的设计

设计了一个新颖的Step-Down电源管理芯片的电流采样电路，能够大幅度的提高Step-Down电源管理芯片的效率，它的输出电平LS1，LTH1和LS2，LTH2分别输入到LIM比较器和PFM电流比较器，控制LIM比较器和PFM比较器，在轻载时使芯片进入PFM工作模式，因此能够延长电池寿命并且大幅度的提高Step-Down PWM电源管理芯片的效率，最后采用HSPICE进行了功能仿真。     

开关电源并联控制系统设计与实现

该设计由自制两个额定输出功率均为16W的8V DC/DC模块并联组成,以STC12LE5A60S2低功耗单片机为控制核心,控制电路自动实现电流分配.每个模块的输出电流的绝对值相对误差小于2％,系统额定输出总电流大于4A.利用霍尔电流传感器ACS712精确测量输出总电流及从模块输出电流,采用闭环负反馈的方式使模块输出电流比无限逼近预置电流比.系统稳定性强,具有精确地短路保护(动作电流为4.5A)及自动恢复功能.     

基于STM32的开关电源模块并联供电系统

本设计以STM32单片机为主控元件产生PWM脉冲,双向DC/DC电路为核心电路,利用以IR2103芯片为主的驱动电路控制双向DC/DC电路中场效应管的开关。电路采用闭环反馈控制,高精度的INA282作为采样电路核心芯片输出反馈信号,单片机根据反馈信号对PWM做出调整,对并联供电系统的输出电流电压进行稳定的步进调整,从而实现稳压输出及电流的不同比例分配。该系统的输出误差和负载调整率低,具有过流保护功能,经测试系统能输出稳定直流电压8V,电流误差绝对值小于2%,供电效率达到70%以上。     

产业信息

ST推出快速响应的高速电压比较器意法半导体(STMicroelectronics,简称ST)推出拥有极佳电流消耗与响应时间比率的高速电压比较器。该高速电压比较器适用于要求极快速响应时间的产品设备(如数据通信设备等),以及音频放大器的脉宽调制器或示波器和模数转换器的输出缓冲器。意法半导体TS3011单路电压比较器在5V电源电压下拥有8ns传播延迟,而电流消耗仅为470μA,这独一无二的能效让客户实现功耗更低且更加环保的产品设计。     

单片电流模式降压型DC-DC转换器的设计

设计了一款内置功率MOSFET的电流模式降压型DC—DC转换器。该DC／DC转换器采用PWM控制，在传统的PWM结构上加入电流反馈环路，改善了传统电压模式DC／DC的缺点，能够取代国际上流行的三端可调线性稳压器。该转换器具有瞬态响应快，启动过冲小，输出纹波小，输出电压可调等特点。正常工作情况，输入电压5～25V，输出电流2A，工作频率400KHz。采用0．8μm BiCMOS工艺模型进行了Spectre模拟，并且制作了该芯片。经过验证，各项指标符合设计要求。     

一种反激式双输出DC/DC变换器的设计与实现

针对市场上DC/DC开关电源高压输出时,输出电压纹波较大问题,介绍了一种±50 V双输出DC/DC开关电源的设计方法及测试结果。该电路采用电流控制型PWM控制芯片,工作于反激模式。输入输出通过光耦实现隔离。该DC/DC变换器具有带负载能力强、纹波低、输出电压高等特点,可为电子设备提供稳定的供电电压。     

具有电压基准的比较器MIC841

MIC841是MICREL公司2000年12月推出的新器件,是一种内部带电压基准的微功耗、高精度电压比较器。外部可设三个电阻来确定要监控的阈值电压,当监控的电压超过设定的阈值电压,比较器输出电平信号。该比较器的特点:工作电压1.5V到5.5V,但输入、输出电压能上拉到6V,而不必考虑工作电压,内部基准电压精度高(±1.25％);工作电流低,典型值     

一种频率稳定的低功耗振荡器电路设计

设计了一种频率稳定的低功耗张弛振荡器电路。采用恒流源对电容两端同时充电和放电,然后将电容两端电压送入后级比较器进行判决,使得输出频率只与恒流源电流、电容以及比较器比较窗口相关。该电路采用GSMC 0.18μm CMOS工艺,在5 V电源电压以及室温条件下仿真,输出频率为123.6 kHz,平均电流消耗为2.67μA;在2 V～5.5 V电源电压和-40℃-+85℃的温度变化范围内,输出频率精度在-6.5%-1.3%范围内。     

ST推出快速响应的高速电压比较器

意法半导体（STMicroelectronics,简称ST）推出拥有极佳电流消耗与响应时间比率的高速电压比较器。该高速电压比较器适用于要求极快速响应时间的产品设备（如数据通信设备等）,以及音频放大器的脉宽调制器或示波器和模数转换器的输出缓冲器。     

PWM整流器保持高功率因数运行的方法研究

针对煤矿井下电压波动严重时影响稳压电源的单位功率因数等问题,提出采用可变输出直流电压法来控制PWM整流器的直流侧电压,以保证PWM整流器处于高功率因数运行的工作状态;详细分析了直流侧电压的选取及交流侧输入电压大范围波动对交流侧输入电流及功率因数的影响,介绍了可变输出直流电压法的控制原则及软件实现。试验结果表明,在电压波动情况下,可变输出直流电压法不仅可使PWM整流器系统稳定,而且可以保持整流器的高功率因数运行状态。     

高精度数控可调直流稳压电源设计

针对常规直流稳压电源的输出电压精度不高和调节较为繁琐的缺点,设计了一款高精度数控可调直流稳压线性电源。该电源输出电压0～30V可调,输出电流最大值可达4A。通过输出电压/电流取样电路、差动放大电路及电压/电流调整电路等所构成的闭环负反馈环节和软件上的双线性插值误差补偿方法,提高了输出电压的精度。该电源输出电压和电流的最大值既可通过旋转编码器和实体按键进行调节,也可以通过在所用触控液晶模块中创建的虚拟键盘直接进行设置,操作简便。实际测试结果表明,该电源的输出电压精度高,12V输出时的负载调整率仅为0.15%,且参数设置操作简便,可满足一般教学、科研的应用需求。     

电流配比可调Buck并联电路变换器设计

本文主要在现有的Buck电路模块基础上,设计了一种实现输出电流可控和多路并联输出电流配比可调的Buck电路变换器。该系统由Buck驱动电路,供电电路,采样电路,控制电路构成。采用ARM公司STM32F407为主控制芯片产生控制驱动功率开关器件IGBT的PWM脉冲,对直流输入电压和各种不同类型的的直流负载实现电压电流双闭环PID算法控制。该系统输出电压闭环控制稳定,可以同时给多个负载进行供电,并且各路输出的电流的比例可调。仿真和实验结果验证了该项设计的稳定性和可行性。     

A novel gate driver circuit for depletion‐mode a‐IGZO TFTs

In this paper, a novel gate driver circuit, which can achieve high reliability for depletion mode in a‐InGaZnO thin‐film transistors (TFTs), was proposed. To prevent the leakage current paths for Q node effectively, the new driving method was proposed by adopting the negative gate‐to‐source voltage (V_GS) value for pull‐down units. The results showed all the V_OUT voltage waveforms were maintained at VGH voltage despite depletion‐mode operation. The proposed circuit could also obtain stable V_OUT voltage when the threshold voltage for all TFTs was changed from ?6.5 to +11.5 V. Therefore, the circuit can achieve high reliability regardless of threshold voltage value for a‐IGZO TFTs. In addition, the output characteristics and total power consumption were shown for the alternating current (AC)–driven and direct current (DC)–driven methods based on 120‐Hz full‐HD graphics (1920 × 1080) display panel. The results showed that the AC‐driven method could achieve improved V_OUT characteristics compared with DC‐driven method since the leakage current path for Q node can be completely eliminated. Although power consumption of the AC‐driven method can be slightly increased compared with the DC‐driven method for enhancement mode, consumption can be lower when the operation has depletion‐mode characteristics by preventing a leakage current path for pull‐down units. Consequently, the proposed gate driver circuit can overcome the problems caused by the characteristics of a‐IGZO TFTs.     

A battery charge controller realized by a flyback converter with digital primary side regulation for mobile phones

A flyback converter with digital control designed and implemented for a lithium battery charging system is proposed in this study. As opposed to the requirement of both voltage and current feedbacks for a conventional flyback converter, this study proposes a converter structure that needs only one voltage feedback to stabilize converter output for implementing the designed battery charging techniques. This single feedback of voltage is made possible by so-called “primary side regulation (PSR)”, which in hardware senses the output voltage using an auxiliary winding in the isolating transformer of the flyback converter that is operated in DC–DC discontinuous current mode. The adoption of PSR also enables the elimination of the opto-coupler that is often used in conventional converters for feedback signals. Another essential part of the converter is the proposition of a new a duty control method which regulate successfully the output current by only one feedback voltage signal. The proposed battery charging design consists of three consecutive modes, trickle current (TC), CC and CV. At TC and CC, a duty control method is adopted, which is able to regulate the output current by sensing only the output voltage. Both simulation and experimental results show a 7 % error deviated from targeted output current. As for CV, a proportional-integral controller is designed and implemented to regulate the output voltage. The overall experimental results show a favorable performance of the proposed charging method with proposed PSR-flyback converter.     

Stability of current-mode control for DC–DC power converters

DC–DC power converters are switched devices whose averaged dynamics are described by a bilinear second-order system with saturated input. In some cases (e.g., boost and buck–boost converters), the input output dynamics can be of nonminimum-phase nature. Current-mode control is the standard strategy for output voltage regulation in high dynamic performance industrial DC–DC power converters. It is basically composed by a saturated linear state feedback (inductor current and output voltage) plus an output voltage integral feedback to remove steady-state offset. Despite its widespread usage, there is a lack of rigorous results to back up its stabilization capability and to systematize its design. In this paper, we prove that current-mode control yields semiglobal stability with asymptotic regulation of the output voltage.     

Passive piezoelectric DC sensor applicable to one-wire or two-wire DC electric appliances for end-use monitoring of DC power supply

A passive, non-contact piezoelectric DC electric current sensor to satisfy the increasing needs of DC power supply for monitoring the electricity consumption by either one-wire or two-wire appliance cord was proposed, and the sensing principle was schematically described and experimentally verified. A micro magnet was integrated into the proposed DC sensor and the appropriate position for locating the micro magnet was theoretically pinpointed. A prototype DC sensor was fabricated, and an impulse piezoelectric voltage output was detected when a DC electric current was applied to a two-wire electrical appliance cord, by using the constructed measurement setup for demonstration. A linear relationship between the detected peak value of the impulse output voltage and the applied DC electric current was further obtained based on the empirical measurements. In light of the above preliminary results, the proposed piezoelectric DC sensor is thus believed to be useful to various kinds of DC electricity end-use monitoring systems without consuming power electricity and using cord separators even in the case of the two-wire appliances.     

基于DPA425的48V-12V反激电源设计

单片开关电源具有体积小、输出纹波小、效率高等特点,在工业生产中得到了广泛的应用.基于PI单片开关电源芯片DPA425 PN设计了一种20 W反激开关电源,开关频率为300 kHz,输入直流42～60 V,输出直流12 V,输出电流0～1.7A.详细描述了反激开关电源的设计过程及参数计算,并给出了电路的原理图以及测试结果.测试结果显示,输出12 V稳定,最大输出电流1.7A,最大输出功率20W,效率可达83％,该电源满足设计需求.     

基于级联H桥逆变器的SVG直流侧电压控制策略

SVG在柔性交流输电中得到广泛应用,其主要缺点之一是各功率单元直流侧的电压不平衡。论文基于功率单元的数学模型和瞬时无功功率理论,深入研究了功率单元电压平衡控制策略。在坐标变换中,取电流矢量为d轴,控制输出电压的直轴分量就可以保持直流侧电压平衡。根据功率平衡原理,提出了控制器的设计计算方法。仿真结果验证了该方法的正确性。