Piezoelectric energy harvesting from vibrations induced by jet-resonator system

Inspired by musical instruments that create high amplitude tones corresponding to resonator acoustic modes when subjected to airflow, a new piezoelectric energy harvester for powering the electronic system of aircrafts is developed. It converts the incoming airflow energy into electricity via a piezoelectric transducer during the flight. With the airflow simulated by an air cylinder, prototypes of the developed energy harvester are fabricated and tested. Experimental results show that the curve of sound pressure, corresponding to the first resonator acoustic mode, is a regular sinusoidal pattern. Within the study range of airflow velocity, a linear relationship can be found not only between sound pressure and airflow velocity but also between open circuit voltage and airflow velocity. A power of above 85 mW is released on a passive electric load of 3 kΩ by using a single piezoelectric element of 10 mm diameter at relative airflow velocity of 159 m/s. And the maximum total energy conversion efficiency of the piezoelectric energy harvester is about 1.2‰. It has laid a solid foundation for powering sensors or other devices, thus eliminating a need for batteries.     

8 Gbits/s inductorless transimpedance amplifier in 90 nm CMOS technology

This work presents the design and the measured performance of a 8 Gb/s transimpedance amplifier (TIA) fabricated in a 90 nm CMOS technology. The introduced TIA uses an inverter input stage followed by two common-source stages with a 1.5 kΩ feedback resistor. The TIA is followed by a single-ended to differential converter stage, a differential amplifier and a 50 Ω differential output driver to provide an interface to the measurement setup. The optical receiver shows a measured optical sensitivity of ?18.3 dBm for a bit error rate = 10^?9. A gain control circuitry is integrated with the TIA to increase its input photo-current dynamic range (DR) to 32 dB. The TIA has an input photo-current range from 12 to 500 μA without overloading. The stability is guaranteed over the whole DR. The optical receiver achieves a transimpedance gain of 72 dBΩ and 6 GHz bandwidth with 0.3 pF total input capacitance for the photodiode and input PAD. The TIA occupies 0.0036 mm² whereas the complete optical receiver occupies a chip area of 0.46 mm². The power consumption of the TIA is only 12 mW from a 1.2 V single supply voltage. The complete chip dissipates 60 mW where a 1.6 V supply is used for the output stages.     

直管谐振式低频压电声能量回收系统

为了高效回收环境中的声能,基于阵列式压电换能器、直管谐振腔以及能量回收电路提出了一种声能量回收系统.当声波进入直管谐振腔,管中产生谐振驻波作用于压电换能器,将声能转换为电能.本文设计了能量回收电路并且进行理论、仿真分析实验研究了压电振子数量、声波频率、声压级对输出电压的影响,分析了负载电阻对输出电压及功率的影响.实验结果表明,该装置可回收不同频率的声能量,在声波频率为96Hz时发电效果最优.当入射声压级为110dB时,不使用能量回收电路,输出交流电压有效值最高达12.9V,输出交流功率最高达到799μW;使用设计的能量回收电路,最高输出直流电压为64.2V,最高输出直流功率为473μW.该声能量回收系统不仅可以作为声能量采集器,还能对无线传感节点等独立工作的微型电子系统供能.     

一种用于红外焦平面读出电路的输出缓冲器

设计了一种应用于红外焦平面读出电路的输出缓冲器,其建立时间短、静态功耗低、线性度高,在77 K和300 K温度下均能正常工作.该输出缓冲器采用0.5 μm CMOS工艺,5.5 V单电源供电,负载为一个25 pF电容并联一个500 kΩ电阻.模拟结果表明,该输出缓冲器在室温(300 K)时,开环增益为54.2 dB,单位增益带宽20 MHz,建立精度为0.1%时,建立时间为45 ns,静态功耗仅为3.3 mW;77 K时,开环增益为63 dB,单位增益带宽123 MHz,建立精度为0.1%时,建立时间为20 ns,静态功耗仅为3.72 mW.     

一种采用频率变换的自供电电源管理电路

 在低频率条件下,采用直接阻抗匹配的原理,设计的压电材料换能器电源管理电路,匹配电感值很大.本文采用频率变换,设计了一种自供电电源管理电路.分析了频率变换的原理.将低频信号变换至较高频率,匹配电感值很小,有利于电路的小型化.该管理电路还可以在宽频带内对于压电换能器实现匹配.实验结果表明,电路实现了频率变换,匹配电感值和电路体积都大大减小.电源管理电路的最大采集功率为181.6mW,能量采集效率可以达到44.8%.当0.47法拉的储能电容电压为1.13V时,该电路最大放电功率可达110mW,放电时间持续620ms,能够驱动无线传感器在一个周期内正常工作.     

单片集成探测器和电吸收调制器光逻辑门

通过在InP基上单片集成光探测器和调制器,制作了三端光逻辑门.在不同的负载电阻下,器件显示了良好的"与"门功能.对芯片进行了622MHz的动态测试;在950Ω负载条件下,只需要约7mw的控制光功率即可获得大于7dB的动态消光比.     

Isolation Amplifier Energized by Ultrasound

A power supply energized by ultrasound has been developed and investigated. The supply can be used in medical applications where a high isolation from earth is essential, for example in the protection of a patient from the hazards of electric shock caused by medical instrumentation. The ultrasound energy is generated by a transmitting piezoelectric crystal (transducer) and sent to a receiving transducer via a glass rod 20 mm long. At the receiving transducer the acoustic energy is converted back to electric energy. The power transmission has been measured at different resonances of the glass rod-transducer combination. The radial mode resonance of the transducer seems to give the largest power transfer and the highest efficiency.     

Polarization-independent integrated optical, acoustically tunabledouble-stage wavelength filter in LiNbO3

We report a polarization-independent integrated acousto-optical double-stage wavelength filter in X-cut, Y-propagating LiNbO₃. The device consists of a combination of four acousto-optical mode converters, a TE- and a TM-pass polarizer, and two polarization splitters; their specific design and properties are discussed. The filter has a bandwidth of 1.4 nm and a tuning range of 76 nm around λ1.55 μm. Maximum filter transmission is achieved with a RF drive power of only 80 mW; it excites via a single unidirectional transducer a guided surface acoustic wave driving the four polarization converters of both stages. Fiber-to-fiber insertion loss is 4.6 dB for TM- and 4.8 dB for TE-polarized waves. Multiwavelength filtering has been demonstrated     

用CMOS工艺实现非接触式IC卡天线的集成化设计

论述了用CMOS工艺实现非接触式IC卡天线的集成化需要考虑的各个方面,建立了集成天线的模型,给出了合理的设计方案,并通过实验验证了模型和设计方案.实验结果表明,采用片上天线完全可以提供非接触式IC卡工作所需要的能量.在频率为22.5MHz、感应强度为6×10-4T的磁场中,面积为2mm×2mm的集成天线可以为10kΩ的负载提供1.225mW的能量.     

一种声学发射换能器的实验研究

采用有强磁化特性的磁性液体作为换能器中制动元件,实验建立一个交变的梯度磁场作用于磁性液体,通过压电陶瓷换能器检测到磁性液体振动而产生的声波,发现磁性液体在交变梯度磁场作用下有磁致伸缩效应。导出了磁性液体振动特性的动力学一般方程,揭示了交变的梯度磁场作用引起了交变的磁性液体的内压强,从而引起磁性液体的体积发生伸缩,产生机械振动,激励空气产生声波的机理。以磁性液体为制动元件可以研制较理想的大功率低频宽带声学发射换能器。     

高指向性声频声源中PVDF膜换能器的阻抗匹配

根据参量阵原理,可以设计出能够发射高指向性可听声的声频声源。相比于传统的压电陶瓷换能器,利用具有特定结构的聚偏二氟乙烯（PVDF）膜作为超声换能器,可以解决困扰高指向性声源输出功率低的问题。研究了PVDF膜超声换能器的电学和声学特性,并据此提出了一种阻抗匹配方法,且经过实验验证,以使得电声转换效率获得了有效的提高。     

声频定向系统电声效率的提升方法和实验研究

压电陶瓷换能器是声频定向传输系统中的发声部件,以往的此类试验系统中,换能器和前级功放电路之间的阻抗匹配问题考虑较少,而阻抗失配会影响整个系统的工作效率,甚至造成功放和换能器的损毁。该文根据压电陶瓷换能器的电学特性,对声频定向传输系统中阻抗匹配对其电声效率的影响进行了研究,提出了该类系统的阻抗匹配理论方法,并通过实验对功放匹配电路的性能进行了测试。结果表明,利用该文所提方法可使距离系统3 m处的最大声压由58 dB增大到73 dB。     

ESD对RuO2厚膜电阻阻值的影响

采用静电放电(Electrostatic discharge,ESD)发生器对RuO2厚膜电阻直接放电,研究了电阻阻值变化率与电阻尺寸、阻值和ESD条件的关系。结果表明:厚膜电阻阻值受ESD作用而下降;相同ESD及阻值条件下的阻值变化率随电阻尺寸的增大而减小;相同电阻的阻值变化率随ESD电压的增大而增大;10kΩ左右的厚膜电阻在ESD作用下的阻值变化率最大,阻值变化率随着阻值的减小和增大而呈减小趋势;对10kΩ厚膜电阻反复施加不断增大的ESD电压,除宽度尺寸为0.45mm的电阻阻值在8～10kV之间出现一次回升外,电阻阻值逐步下降。     

A Novel Quarter-Circular Arc Multi-Direction Piezo electric VEH and Its Theoretical Model

A quarter-circular arc piezoelectric Vibra-tion energy harvester (VEH) based on nonlinear geometry is proposed with both bending moment and torque deformation mode, so it can effectively absorb multi-directional vibration at the same resonance frequency. The theoretical model of quarter-circular arc piezoelectric VEH is established to study the resonance frequency and the output voltage. In order to demonstrate multi-directional performance of the quarter-circular arc VEH, the stress distribution is compared with that of the traditional piezoelectric VEH in multi-direction vibration, and the output voltage of the circular arc piezoelectric VEH are relatively increased 267.26％ in X-direction, 463.18％ in Y-direction, and 17.24％ in Z-direction. The external load is equipped in circuit to measure output power, whose matching resistance is around 21k?, and the maximum output powers are 7.57mW in X-direction, 2.39mW in Y-direction, and 9.93mW in Z-direction.     

可用于光纤用户网的0.6μm CMOS激光驱动器

基于国内的CMOS技术和EDA工具以及全定制的设计方法,采用无锡华晶上华(CSMC-HJ)0.6μm CMOS技术实现了可工作于155Mb/s、622Mb/s的激光驱动器.该激光驱动器在50Ω负载上输出电流摆幅从0到50mA可调.在输出级3V直流偏置时最大输出电压摆幅可达2.5Vpp.输出电压脉冲的上升、下降时间分别小于471ps和444ps.四个工作速率下均方根抖动都小于30ps.电路在5V单电源供电时功耗小于410mW.芯片测试结果表明,该激光驱动器达到了世界同类集成电路的水平.     

一种用于UHF RFID的低压高效电源产生电路

介绍了一种为无源UHF RFID设计的高效高灵敏度电源产生电路.该电路基于0.18μm工艺,其中包含了两个电荷泵,一个参考电流源和一组偏置电路.由于其偏置电路消除了传统电路中的阈值损失和体效应,使该电路在低压下的电源转换性能得到很大的提高.要为100kΩ负载提供1.5V电源电压,所需最小输入电压为350mV,转换效率为22%.在负载为60kΩ时,最高可以获得29.8%的转换效率.仿真结果表明,新的电路结构比传统的电荷泵具有更优越的性能.     

固结磨料超声磨削用压电换能器等效阻抗分析

固结磨料超声磨削加工过程中,随着负载的快速变化,压电换能器必须保持快速的频率跟踪与功率匹配响应,才能满足高效精密加工需求。该文从微观角度分析了固结磨料超声磨削的材料去除过程,通过建立压电换能器的力学模型,基于力电类比,得出压电换能器的等效阻抗与负载变化关系,即换能器的负载越大,其等效阻抗越大。当采用恒压源驱动压电换能器时,当换能器的负载越大,输出功率越小;反之,负载越小,输出功率越大,换能器无法工作在最佳状态。因此,为改善加工稳定性,提高材料表面完整性,提出了压电换能器的智能化恒流激励电源驱动方案,并进行了空载和负载状况下的电源系统测试试验,为进一步展开相关加工工艺研究奠定了坚实的基础。     

复频聚焦超声压电换能器声场及频谱的研究

研制了一种新型复频变超声换能器,并从理论上计算了辐射声压在轴向上的分布曲线,进而确定了焦区位置,这与实验所得结果符合得较好。文章还对换能器在水中焦区辐射声场的频谱进行了研究,观测到了两个原波。和频波,差频波及倍频波,证实了声散射声效应的存在。     

复频超声波清洗器的研制

通过改变夹心式换能器压电晶片的堆放位置及组数,使超声清洗换能器具有两个明显的谐振峰。经自动控制及转换电路,使超声波电源既能在任一单频工作又能在双频自动交替工作。大功率实用状态下清洗复杂工件,并用染色法真实记录单频工作及双频交替工作时槽内声场的分布情况。结果表明,复频超声清洗能充分发挥不同频率的声波特性,比单频清洗效果更好。     

多悬臂梁压电换能器电路的设计与实现

介绍了一种多悬臂梁压电换能器电路。与标准能量采集电路(SEH)相比,三悬臂梁压电换能器电路的理论最大平均采集功率提高了300%。利用Multisim软件仿真,结果表明,三悬臂梁压电换能器电路的最终输出电压为SEH电路的2.11倍;进一步搭建实际电路,其最终最大输出功率为SEH电路的3.12倍,能量转化与利用效率显著提高。