应用于热电能量收集的低压自启动电路

设计了一种两级低电压自启动电路,实现低输入电压条件下热电能量收集系统的自启动。在第一级自启动电路中引入一种新型堆叠式反相器,构成环形振荡器结构,在低供电电压下产生较大的振荡摆幅;第二级自启动电路由高幅值时钟产生电路与电感复用升压电路构成,进一步提高输出电压;由电压检测电路以及辅助电路构成的控制电路实现了第一级自启动向第二级自启动的转换,以及第二级自启动向主升压转换的过程。基于0.18 μm CMOS工艺设计该自启动电路,版图后仿真结果表明,在190 mV的TEG输入电压,以及11.8 μA的负载电流情况下,自启动电路可产生825 mV输出电压,转换效率可达到56.5%,实现能量收集系统的自启动功能,保证后级主升压电路的正常工作。     

基于环境微弱能量收集的低阈值CMOS电路设计

环境中存在着丰富的电磁波能量,而人体运动产生的机械能则是一种不受外界干扰非常稳定的能源,这些能源的存在使设备为自身供电成为可能.由于射频电磁波能量和振动能量密度低的特性,设计了一种能够匹配低功耗低电压的复合能量收集与管理电路.该电路采用0.18 μm标准CMOS工艺,对电源转化模块、电源调节模块(整流电路、滤波电路、升压电路,以及为升压电路提供时钟信号的振荡电路)和储能模块进行了分析与设计.整流电路的最低输入电压为200 mV,整流效率达到75％.升压电路采用新型电荷泵电路,具有4.8倍升压效果,输出电压最高达到970 mV,电压纹波率为0.5％.当输入电流为50 μA时,该电路转换率为10％,输出平均功率为1.14μW.     

胶囊内窥镜中高效全向能量接收芯片的设计

能量接收电路最主要的性能参数为功率转换率。为了提高电压转换率和功率转换率,通过对全向能量接收电路的理论分析,提出了使用低功耗高速比较器来控制mos管开关的方法。同时分析了闩锁效应,采用CMOS工艺设计了一种应用于胶囊内窥镜的高效全向能量接收电路。并用CSMC 0.5um工艺对该电路进行了仿真,仿真结果表明,该电路的电压转换效率可达97%,满足内窥镜对能量的要求。     

采用前端变压器的射频电磁波能量收集器设计

为了实现高灵敏度的电磁波能量收集,提出了一种采用前端变压器的射频电磁波能量收集器。该电路具有一个前端变压器和18级整流器,可使收集电路与一个标准的50天线相匹配,同时提供电压增益,从而减少了18级整流器的“死区”。设计的电路采用了标准130-nmCMOS工艺,面积为200 × 250 μm2。实验结果表明,提出的能量收集器电路能够与50Ω天线相匹配,且具有?25 dBm灵敏度。     

面向风力发电系统的交直流混合升压转换器

为提高风力发电系统中压功率转换器的性能,提出了一种用于风力发电系统中压直流转换的混合式高增益转换器,该转换器由升压谐振电路和耦合电压四倍频器组成,具有升压电压转换功能。其中,耦合电压四倍频模块通过1∶1∶1高频变压器连接到谐振电路,不需要高匝数比变压器;其次,利用高频整流级输入端的耦合电感构成电流型高增益整流器,保证二极管的平滑性能,消除二极管反向恢复损耗;然后,通过在输出整流级对电压四倍器进行磁耦合,实现电压平衡控制;最后,变频器模块采用变频控制输出电压。经过4MW模块化设计的SiC转换器系统仿真和实验室规模的样机实验,结果表明,转换器峰值效率接近99%。     

压电能量采集器高效能量提取接口电路设计

压电能量采集器能把环境振动能转换为电能,该文基于如何将压电能量采集器转化电能最大化提取的研究,提出了一种压电能量采集器高效能量提取接口电路,采用有源二极管整流电路降低了整流过程中的导通压降损耗,电感同步开关电荷提取电路有效提取了寄生电容中储存的电能。利用华虹宏力0.11 μm CMOS工艺进行电路设计和版图布局。测试结果表明,接口电路可提取80.4%寄生电容中存储的电能,20 kΩ电阻负载下导通压降为20.2 mV,在加速度5g(g=9.8 m/s2)和频率40 Hz条件下平均提取功率是标准接口电路的2.58倍。该芯片可应用于基于振动能供电的无线无源传感节点等领域。     

基于CMOS工艺高速光纤通信系统的限幅放大器

基于CMOS工艺,设计了高速光纤通信系统中的限幅放大器,主要包括四部分:输入缓冲级、输出缓冲级、宽带放大单元和失调电压补偿回路.其中宽带放大单元采用有源反馈技术和并联峰化技术扩展带宽,使限幅放大器的带宽达到6.8GHz,增益为46dB.当输入信号比特率为7Gb/s,输入电压峰峰值在10mV到1V之间波动时,输出摆幅稳定在1.4V.在标准的1.8V电源电压下,整体电路功耗为192.3mW.     

恒跨导高摆率轨对轨运算放大器的设计

本文在分析MOS管恒跨导输入级和AB类输出级运算放大器的基础上设计了一个高摆率、恒跨导的轨对轨运算放大器。在输入级中采用了齐纳二极管的稳压原理,保证Rail-to-Rail运算放大器的输入跨导恒定。为了实现高转换率,本文采用了一种新型的压摆率提高电路。另外,为了提高系统的稳定性,采用了控制零点的米勒补偿进行频率补偿。采...     

一种二极管桥式跟踪保持电路设计

设计了一种基于二极管桥的两级全差分跟踪保持电路,两级模块由独立的时钟控制,可以各自工作在跟踪模式。芯片采用1μm GaAs HBT工艺实现,芯片大小为1.8mm×2mm,功耗2.75W。经测试,电路可以工作在1GS/s采样速率下,单端输入峰峰值250mV信号时采样带宽超过7GHz;单端输入峰峰值250mV,DC-2GHz信号时,电路具有8bit有效位。     

一种低失调高压大电流集成运算放大器

基于结型场效应晶体管(JFET)和双极型晶体管(BJT)兼容工艺,设计了一种低失调高压大电流集成运算放大器。电路输入级采用p沟道JFET (p-JFET)差分对共源共栅结构;中间级以BJT作为放大管,采用复合有源负载结构;输出级采用复合npn达林顿管阵列,与常规推挽输出结构相比,在输出相同电流的情况下,节省了大量芯片面积。基于Cadence Spectre软件对该运算放大器电路进行了仿真分析和优化设计,在±35 V电源供电下,最小负载电阻为6Ω时的电压增益为95 dB,输入失调电压为0.224 5 mV,输入偏置电流为31.34 pA,输入失调电流为3.3 pA,单位增益带宽为9.6 MHz,具有输出9 A峰值大电流能力。     

Transformer‐Reuse Reconfigurable Synchronous Boost Converter with 20 mV MPPT‐Input, 88% Efficiency,and 37 mW Maximum Output Power

This paper presents a transformer‐based reconfigurable synchronous boost converter. The lowest maximum power point tracking (MPPT)‐input voltage and peak efficiency of the proposed boost converter, 20 mV and 88%, respectively, were achieved using a reconfigurable synchronous structure, static power loss minimization design, and efficiency boost mode change (EBMC) method. The proposed reconfigurable synchronous structure for high efficiency enables both a transformer‐based self‐startup mode (TSM) and an inductor‐based MPPT mode (IMM) with a power PMOS switch instead of a diode. In addition, a static power loss minimization design, which was developed to reduce the leakage current of the native switch and quiescent current of the control blocks, enables a low input operation voltage. Furthermore, the proposed EBMC method is able to change the TSM into IMM with no additional time or energy loss. A prototype chip was implemented using a 0.18‐μm CMOS process, and operates within an input voltage range of 9 mV to 1 V, and an output voltage range of 1 V to 3.3 V, and provides a maximum output power of 37 mW.     

A small, low power boost regulator optimized for energy harvesting applications

A small, low power bootstrapped boost regulator is introduced that can start up with an input voltage of 240 mV and achieve a maximum efficiency of 97 %. The proposed circuit uses two separate control schemes for startup and steady-state operation. A fixed-frequency oscillator is used to initially start up the circuit and raise the output voltage. Once the output voltage has reached a level adequate to bias the internal circuitry, a constant-on-time style hysteretic control scheme is used, which helps increase system efficiency compared to using a conventional pulse-width-modulated control scheme. While maintaining a high efficiency, the proposed circuit only requires three external components: two capacitors (input and output) and an inductor. The effectiveness of this approach is shown through Spectre simulation results.     

An active power factor correction technique for three-phase dioderectifiers

A novel active power factor correction method for power supplies with three-phase front-end diode rectifiers is proposed and analyzed. The implementation of this method requires the use of an additional single switch boost chopper. The combined front-end converter draws sinusoidal AC currents from the AC source with nearly unity input power factor while operating at a fixed switching frequency. It is shown that when the active input power factor correction stage is also used to regulate the converter DC bus voltage, the converter performance can improve substantially in comparison with the conventional three-phase AC-to-DC converters. These improvements include component count reduction, simplified input synchronization logic requirements, and smaller filter refractive components. Theoretical results are verified experimentally. The proposed method has the disadvantage of substantially increasing the current stresses of the switching devices and the high-frequency ripple content of the prefiltered AC input currents     

A constant output current three-phase diode bridge rectifier employing a novel "Electronic Smoothing Inductor"

This paper presents an improvement of the well-known conventional three-phase diode bridge rectifier with dc output capacitor. The proposed circuit increases the power factor (PF) at the ac input and reduces the ripple current stress on the smoothing capacitor. The basic concept is the arrangement of an active voltage source between the output of the diode bridge and the smoothing capacitor which is controlled in a way that it emulates an ideal smoothing inductor. With this the input currents of the diode bridge which usually show high peak amplitudes are converted into a 120/spl deg/ rectangular shape which ideally results in a total PF of 0.955. The active voltage source mentioned before is realized by a low-voltage switch-mode converter stage of small power rating as compared to the output power of the rectifier. Starting with a brief discussion of basic three-phase rectifier techniques and of the drawbacks of three-phase diode bridge rectifiers with capacitive smoothing, the concept of the proposed active smoothing is described and the stationary operation is analyzed. Furthermore, control concepts as well as design considerations and analyses of the dynamic systems behavior are given. Finally, measurements taken from a laboratory model are presented.     

New design of RF rectifier for passive UHF RFID transponders

A novel diode-connected MOS transistor for ultra-high-frequency (UHF) micro-power rectifiers was presented, and a high efficiency N-stage charge pump voltage rectifier based on this new diode-connected MOS transistor was designed and implemented. The new diode-connected MOS transistor and the rectifier are designed and fabricated in SMIC 0.18-μm 2P3M CMOS embedded EEPROM process. The structure design of the new diode achieved 315 mV turn-on voltage, and 415 nA reverse saturation leakage current. Compared with traditional rectifier, the rectifier using the presented diode-connected MOS has higher power conversion efficiency (PCE), higher output voltage and smaller ripple coefficient. When the RF input is a 900-MHz sinusoid signal with the amplitude ranging from 0.8 to 1.8 V, PCEs of the charge pump rectifier with only 3-stage are more than 30%, and the maximum output voltage is 5.02 V, and its ripple coefficients are less than 1%.     

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。     

箝位二极管承受低电压的有源箝位谐振直流环节逆变器

为解决无源箝位谐振直流环节逆变器辅助电路中采用耦合电感辅助换流（即抽头电感法）所引起的箝位二极管两端承受的电压应力过大问题,提出一种箝位二极管承受低电压的有源箝位谐振直流环节逆变器,该逆变器采用有源箝位的方法可使箝位二极管两端承受的最大反向电压不超过直流母线电压的最大值.且该逆变器的辅助谐振电路中只有一个辅助开关器件,箝位电路中无需设置箝位开关,控制简单且硬件成本较低.此外,在箝位电路的作用下可将逆变器的直流母线电压箝位在输入直流电压的1.1~1.3倍,有效地降低了电压应力.以各个阶段下的等效电路为基础,对电路的工作过程进行了分析,并进行了实验验证,实验结果表明开关器件实现了软开关,且在额定功率3kW条件下,逆变器的效率达到96.5%.因此,该拓扑结构能够有效地提高工作效率.     

A novel ultra low power ASK demodulator for a passive UHF RFID tag compatible with C1 G2 EPC standard protocol

In order to reduce the power consumption of RFID tags and increase the reading range of RFID systems, this paper proposes an ASK demodulator that uses a new approach to reduce the threshold voltage of diode connected MOS transistors as an obstacle in the design of the envelope detector. Also, an ultra low power comparator is used for further power reduction. This circuit has been simulated in a 0.18 μm CMOS technology to satisfy EPC Class 1 Generation 2 standard protocol emphasizing on the reduction of power consumption. The proposed circuit can correctly demodulate the minimum input RF signal amplitude of 180 mV for modulation depths of 55–100 % with 40–160 kb/s data rates. A total power consumption of less than 290 nW is achieved at a 1.2 V power supply. Effects of the input signal additive white noise as well as the process and temperature variations on the signal demodulation is also investigated in this paper.     

一种新型软开关DC-DC PWM升压变换器设计

为提高转换效率并降低电源开关的电流应力,提出一种基于新型有源缓冲电路的PWM DC-DC升压变换器。该有源缓冲电路使用ZVT—ZCT软开关技术,分别提供了总开关ZVT开启及ZCT闭合、辅助开关ZCS开启及ZCT闭合。消除了总开关额外的电流及电压应力,消除了辅助开关电压应力,且有源缓冲电路的耦合电感降低了电流应力。另外,通过连续将二极管添加到辅助开关电路,防止来自共振电路的输入电流应力进入总开关。实验结果表明,相比传统的PWM变换器,新的DC-DC PWM升压变换器在满负荷时电流应力降低且总体效率能达到98.7%。