具有阈值可编程信号检测功能的BiCMOS限幅放大器

采用0.6 μm BiCMOS工艺,设计了一种应用于FTTH(光纤到户)的限幅放大器.该限幅放大器采用PECL电平输出,动态范围宽,信号增益高,输入差分信号1.6～800 mV,单端输出电压摆幅约800 mV,具有阈值可编程的信号丢失检测功能和信道阻塞功能,适用于FTTH级别的光接收机.     

全摆幅运算放大器的设计

设计了一种全摆幅输入的运算放大器。通过恒定跨导结构实现互补输入差分对共模输入电压在轨到轨范围内对恒定跨导的控制。设计中在输出结构里使用了电流求和电路,以达到输出信号相加,实现单端输出的功能。采用Spectre进行仿真,电源电压5V时,低频增益84dB,单位增益带宽12MHz。     

二极管型非制冷红外探测器的前端电路设计

设计了一种二极管型非制冷红外探测器的前端电路,该电路采用Gm-C-OP积分放大器的结构,将探测器输出的微弱电压信号经跨导放大器(OTA)转化为电流信号,再经电容反馈跨阻放大器(CTIA)积分转化为电压信号输出。该OTA采用电流反馈型结构,可以获得比传统OTA更高的线性度和跨导值。输入采用差分结构,可以有效地消除环境温度及制造工艺对探测器输出信号的影响。电路采用0.35 m CMOS工艺进行设计并流片,5 V电源电压供电。Gm-C-OP积分放大器总面积0.012 6 mm2,当输入差分电压为0~5 mV时,测试结果表明:OTA跨导值与仿真结果保持一致,Gm-C-OP积分放大器可实现对动态输入差分信号到输出电压的线性转化,线性度达97%,输出范围大于2 V。     

差分测量的重要性

许多实际应用都要求放大强噪声环境中的徵弱信号。通常，信号传感器离放大器有一定的距离，所以经常引入大量的噪声和杂音。有效的信号恢复常常依赖于为具体的应用精心地选择最佳的放大器。有三种常见的应用系统类型：单端输入和单端输出(基于运算放大器)系统；差分输入和单端输出(基于仪表放大器)系统；以及差分输入和差分辅出(基于差分放大器)系统。有些设计工程师可能要使用单端输人、屏蔽电缆系统，类似图A所示。这里，首先在屏蔽电缆和公共端(或者“地”)之间施加输入信号，然后它通过电缆传送到运算放大器。像这样的单端系统很容易引…     

差分测量的重要性

许多实际应用都要求放大强噪声环境中的微弱信号。通常,信号传感器离放大器有一定的距离,所以经常引入大量的噪声和杂音。有效的信号恢复常常依赖于为具体的应用精心地选择最佳的放大器。有三种常见的应用系统类型:单端输入和单端输出(基于运算放大器)系统;差分输入和单端输出(     

基于偏流补偿的低失调运算放大器的设计

基于双极型工艺,设计了一种具有低输入失调电压、低输入偏置电流的运算放大器。电路结构包含偏置电路、差分输入级电路、中间级电路和输出级电路。差分输入级电路采用共射-共基耦合对,能够降低失调电压,并且采用基极电流补偿结构抵消输入偏置电流在外围电路上所产生的影响,提高电路精度。中间级为整个电路提供增益,并且将双端输入信号转换为单端输出信号。输出级电路为AB类输出级,具有低静态功耗,能够提高电路效率,增大电路带负载能力并为负载提供更多功率。电路采用齐纳修调技术,在封装后对芯片进行修调,避免封装后引入的二次失调。流片后测试结果表明：在±15 V电源电压条件下,输入失调电压≤10μV,输入偏置电流≤3 nA,输入失调电流≤1.5 nA,大信号电压增益≥110 dB。     

ACPL-782T：汽车用小型隔离放大方案

Avago公司的ACPL-782T是在电子马达驱动器和电池系统监控中使用的小型绝缘放大器,用于电压和电流检测。在典型应用中,马达电流流过一个外部电阻器,产生的模拟压降被ACPL-782T检测。在ACPL-782T光隔离屏障的另一端,生成了差分输出电压。差分输出电压同马大电流成比例,并且利用在推荐应用电路中使用的光放大器可以将其转换为单端信号。     

基于偏振调制型全光纤电流互感器的研究

随着电力系统输电电压等级和传输容量的不断提高,传统的电磁式电流互感器暴露出诸多问题已难以满足当今社会的需要。本系统通过对光纤电流互感器的理论基础进行了深入的研究,并在此基础上建立了光纤电流互感器数学模型;根据模型设计了光纤电流互感器光路系统,并根据光路特点选择了相关器件;根据光路系统输出信号的特点,设计了激光器驱动电路和光纤电流互感器信号检测电路,对检测电路的性能进行了单独测试;最后,设计了光纤电流互感器准确度测试系统,并对所设计的光纤电流互感器系统进行了整体测试。测试结果表明,在相同的测试环境下,该光纤电流互感器的输出具有极好的线性,测试结果符合 IEC 0.2S 级。     

一种用于生物信号采集的CMOS全差分前置跨阻放大器设计

针对生物信号微弱、变化范围大等特点设计了一种用于检测微弱电流的全差分跨阻放大器(TIA)电路结构。不同于传统电路的单端输入,该结构采用高增益的全差分两级放大器实现小信号输入及轨到轨输出。基于CSMC 0.18μm CMOS工艺,采用1.8V电源电压对设计的电路进行了仿真,仿真结果表明:TIA输入电流动态范围为100nA^10μA,最大跨阻增益达到104.38dBΩ,-3dB带宽为4MHz,等效输入噪声电流为1.26pA/Hz。对电路进行跨阻动态特性仿真表明,在输入电流为100nA时,输出电压的动态摆幅达到3.24mV,功耗仅为250μW,总谐波失真(THD)为-49.93dB。所设计的高增益、低功耗、宽输入动态范围TIA适用于生物医疗中极微小生物信号的采集,可作为模块电路集成在便携设备中。     

电流模式n阶OTA—C滤波器的设计

提出了设计电流模式ｎ阶ＯＴＡ－Ｃ滤波器的新方法：使用单端输入，双端输出的电流放大器及单端输入，三端输出的电流积分器对ｎ阶电流传递函数的信号流图进行综合。     

Non-linear model for FET differential amplifier

A simple formula is presented for the relationship between an input differential voltage and the corresponding output differential current of an FET differential amplifier. Also, a closed-form expression is derived for the output signal of a differential amplifier excited by a multi-sinusoidal input signal.     

A 1 V CMOS programmable accurate charge pump with wide output voltage range

A 1 V, programmable, accurate, high speed, single-ended charge pump is proposed, suitable for low voltage PLLs. It is designed in TSMC 90-nm digital CMOS process and it consists of four switches in a current steering configuration, a unity gain rail to rail buffer for the charge sharing effect elimination, one more rail to rail amplifier for minimizing the DC current mismatch, a programmable current bias circuitry and two drivers based on the standard cell XOR gates specific configuration for achieving good synchronization between all charge pump input pulses at the PLL lock state. Replica biasing technique is applied to all charge pump switches. Current glitches and charge mismatch are suppressed by employing a mechanism with additional switches at the output. It exhibits a maximum DC current mismatch of 1% and charge mismatch of 6% over a wide output voltage range of 0.7 V for the entire range of output currents. The wide range of the output voltage remains relatively constant and independent of the selected charge pump current amplitude. This is attained by applying appropriate variation of the W/L ratios of the bias cascode current sources via the employment of additional programmable switches such that their saturation voltages remain relatively constant, something which in turn enables the output currents range to be as wide as it is required.     

Am improved tail current source for low voltage applications

A new current source for low-voltage applications is proposed. This current source is well suited for biasing differential pairs and source followers. Measured compliance voltage is slightly smaller than that of a single transistor. Its output resistance is a factor of 25 larger than that of a single transistor current source and was measured to be 8 MΩ. The use of the new current source improves the common-mode input range and the common-mode rejection ratio of fully balanced and single-ended differential amplifiers     

一种基于UC2844的单端反激式高频稳压开关电源

本文设计了一种以UC2844电流型PWM控制器控制,多路输出的单端反激式开关电源。根据UC2844的电流控制模式给出以单端反激式拓扑结构和峰值电流PWM技术为基础的设计方法,通过测试得到的信号波形说明了本方法设计出的开关电源可以减小纹波和提高电源效率,保证电压的稳定输出。     

Current-source parallel-resonant DC/AC inverter with transformer

This paper gives the theory and experimental results for a current-source parallel-resonant inverter with a transformer used to change voltage levels and provide isolation. The analysis is performed in the frequency domain using Fourier series techniques to predict output power, efficiency, DC-to-AC voltage transfer function, and component voltage and current stresses. The inverter consists of two switches, a large choke inductor, a transformer, and a parallel-resonant circuit. The magnetizing inductance of the transformer is used as the inductance of the parallel-resonant circuit, thereby requiring one less component. Each switch consists of a MOSFET in series with a diode. The MOSFETs have their sources grounded so there is no need for a complicated gate-drive circuit. An inverter was designed and constructed. The DC input voltage was 156 V and the output voltage was a sine wave with a peak value of 224 V at an operating frequency of 50 kHz. The output power at full load was 100 W     

155Mbps速率级0.5μmCMOS限幅放大器

描述了用于SDH光纤通信STM-1速率级光接收机主放大器的155 Mbps限幅放大器.该电路采用CSMC0.5 μm CMOS工艺实现,供电电压为3.3 V,功耗为198 mW.核心电路包含6级级联的传统差分放大器,一个输出缓冲和一个直流失调补偿反馈环路.通过调整片外电阻Rset,小信号增益在44～74 dB范围内可调.芯片封装后测试得到的输入动态范围为54 dB(Rset=50Ω),单端输出摆幅为950 mV,在高达400 Mbps伪随机码输入时,所得眼图仍然令人满意.     

降压型DC/DC开关电源中的电压前馈技术

介绍了一种应用于降压型DC/DC开关电源的电压前馈技术,通过调整内部三角波的中心电压,使PWM信号占空比跟随输入电源电压快速改变。该技术能有效抑制输入电源电压变化对输出电压的影响,增强输出电压的稳定性。     

CMOS high linearity PA driver with an on-chip transformer for W-CDMA application

A fully integrated high linearity differential power amplifier driver with an on-chip transformer in a standard 0.13-μm CMOS process for W-CDMA application is presented.The transformer not only accomplishes output impedance matching,but also acts as a balun for converting differential signals to single-ended ones.Under a supply voltage of 3.3 V,the measured maximum power is larger than 17 dBm with a peak power efficiency of 21%.The output power at the 1-dB compression point and the power gain are 12.7 dBm and 13.2 dB,respectively. The die size is 0.91×1.12 mm~2.     

An Improved Topology of SEPIC Converter With Reduced Output Voltage Ripple

An improved version of a single-ended primary inductor converter (SEPIC) is presented. The converter consists of a conventional SEPIC converter plus an additional high-frequency transformer and diode to maintain a freewheeling mode of the dc inductor currents during the switch on state. The voltage conversion ratio characteristics and semiconductor device voltage and current stresses are characterized. The main advantages of this converter are the continuous output current, smaller output voltage ripple, and lower semiconductors current stress compared with the conventional SEPIC converter. The design and simulation of the concept is verified by an experiment with a 48-V input and 12-V/3.75-A output converter.