采用NCP1205构成的反激变换器研究与仿真

NCP1205是安森美公司新推出的一款单端PWM控制器模块。它集成了一个电流控制调节器和一个去磁检测器,目的是确保电路在准谐振模式下,在任何负载和任何线性条件下都能够工作在不连续状态,并能够使开关管开通时实现损耗最小。文中介绍了NCP1205的内部组成、管脚功能及工作原理,并给出了所研制电源的电路及其仿真波形。     

适于视频应用的高数据传输率集成CMOS收发机

这篇文章给出了一个5GHz CMOS射频收发机的设计方案。此设计采用0.18微米射频CMOS加工工艺,集合了最新IEEE802.11n的特性例如多输入多输出技术的专利协议以及其他无线技术,可提供应用在家庭环境中的实时高清电视数据的无线高速传输。设计频率涵盖了从4.9GHz到5.9GHz的ISM频带,每个射频信道的频宽为20MHz。收发机采用了直接上变频发射器和低中频接收器的结构。在没有片上校准的情况下,设计采用双正交直接上变频混频器,得到了超过35dB的镜像抑制。测试结果得到6dB接收机噪声系数以及在-3dBm输出功率时得到发射机EVM结果优于33dB。     

高精度低噪声MEMS陀螺仪电容读出电路

在研究电容式微机械陀螺信号通路工作原理的基础上,分析了影响电容式读出电路精度的各种非理想因素并进行了量化计算,设计了一款低噪声电容读出电路。该芯片采用高频调制原理实现了低频噪声的转移,同时提出了一款具有高电源抑制比的低噪声运算放大器,采用连续时间的电容读出方法研制了微机械陀螺ASIC电路。该芯片采用0.5μm CMOS工艺,芯片面积为3.5mm×3.4 mm,测试结果表明,该单片ASIC的输出级噪底为-117 dB,当陀螺仪量程为±300°/s时,分辨率可以达到0.00035°/s。     

Association of the C-Reactive Protein Gene (CRP) rs1205 C>T Polymorphism with Aortic Valve Calcification in Patients with Aortic Stenosis

Elevation in C-reactive protein (CRP) levels have been shown in patients with aortic valve stenosis (AS). Minor allele of the CRP gene (CRP) rs1205 C>T polymorphism has been associated with lower plasma CRP concentrations in cohorts of healthy and atherosclerotic patients. Considering the existing similarities between atherosclerosis and AS, we examined the effect of CRP rs1205 C>T polymorphism on the AS severity. Three hundred consecutive Caucasian patients diagnosed with AS were genotyped for the rs1205 C>T polymorphism using the TaqMan assay. Severity of the AS was assessed using transthoracic echocardiography. The degree of calcification was analyzed semi-quantitatively. Carriers of the rs1205 T allele were characterized by elevated serum CRP levels (2.53 (1.51–3.96) vs. 1.68 (0.98–2.90) mg/L, p < 0.001) and a higher proportion of the severe aortic valve calcification (70.4% vs. 55.1%, p = 0.01) compared with major homozygotes. The effect of CRP rs1205 polymorphism on CRP levels is opposite in AS-affected than in unaffected subjects, suggesting existence of a disease-specific molecular regulatory mechanism. Furthermore, rs1205 variant allele predisposes to larger aortic valve calcification, potentially being a novel genetic risk marker of disease progression.     

基于无线射频芯片XE1205的数传模块设计与实现

基于无线射频芯片XE1205构建了一种新型的无线数据传输模块;硬件系统利用ARM7芯片LPC2148对XE1205进行配置和读写控制,使用简单的阻抗匹配电路、时钟振荡电路、射频开关电路,实现了无线收发功能;软件方面包括对XE1205的配置编程,数传功能的软件实现等;此模块具有结构简单、配置灵活,传输可靠、通用性强、成本低的显著特点.     

Advances in piezoelectric thin films for acoustic biosensors,acoustofluidics and lab-on-chip applications

Recently, piezoelectric thin films including zinc oxide (ZnO) and aluminium nitride (AlN) have found a broad range of lab-on-chip applications such as biosensing, particle/cell concentrating, sorting/patterning, pumping, mixing, nebulisation and jetting. Integrated acoustic wave sensing/microfluidic devices have been fabricated by depositing these piezoelectric films onto a number of substrates such as silicon, ceramics, diamond, quartz, glass, and more recently also polymer, metallic foils and bendable glass/silicon for making flexible devices. Such thin film acoustic wave devices have great potential for implementing integrated, disposable, or bendable/flexible lab-on-a-chip devices into various sensing and actuating applications. This paper discusses the recent development in engineering high performance piezoelectric thin films, and highlights the critical issues such as film deposition, MEMS processing techniques, control of deposition/processing parametres, film texture, doping, dispersion effects, film stress, multilayer design, electrode materials/designs and substrate selections. Finally, advances in using thin film devices for lab-on-chip applications are summarised and future development trends are identified.     

基于旋变数字转换器的PMSM转子位置获取

在分析旋转变压器和旋转变压器数字转换器AD2S1205工作原理的基础上,重点阐述基于旋转变压器、AD2S1205及永磁同步电机(PMSM)控制器中的数字信号处理器(DSP)进行PMSM转子位置获取的接口电路设计.在完成基于Cadence/Pspice软件对接口电路的硬件仿真分析之后,再通过PMSM系统实验对所设计的接口电路进行实验验证,证实了所设计的接口电路具有简单可靠,抗干扰能力强的特点,能够实现电动汽车PMSM驱动系统转子位置的准确获取.     

旋转变压器数字转换器AD2S1205在电机转子位置检测中的应用

文中介绍了一种永磁同步电机转子位置检测方法,使用DSP的并口模拟SPI读取AD2S1205转换的位置信息。AD2S1205是最新的单芯片旋变数字转换器,将旋转变压器输出的模拟信号转化为数字信号。文中阐述了旋转变压器、AD2S1205的工作原理及其信号引脚,结合TMS320LF2406A,给出了一种永磁同步电机转子位置检测的通讯接口方法及应用示例。     

ISO15693非接触式IC卡射频前端电路的设计

介绍了ISO15693非接触式IC卡射频前端电路,采用了一种巧妙的整流电路,提高了整流效率。同时使用了一种适用于ISO15693非接触式卡片的简单的稳压电路结构,有助于信号的解调,并且使卡片在接收到的信号为10％ASK和100％ASK两种调制模式时都能正常工作。芯片测试结果显示：电源产生电路能够产生2．2V-3．8V的直流电压,解调电路能够在2．0V-3．8V电压下可靠稳定的工作;在ISO15693规定的最小场强0．15A／M处,整个芯片的电源电压为3．3V,且功耗小于60μW。     

一种新型反激变换器的研究

本文基于NCP1205芯片设计了一种新型准谐振反激变换器。在分析该变换器工作原理的基础上,进行了电路设计和工作频率计算。由实验结果,新型反激变换器具有良好的负载调整率、动态响应快、输出电压纹波小及开关损耗低的特点。