叠层片式陶瓷电感器寄生电容的提取

寄生电容是叠层片式电感器的重要参数,对电感器的Q值和谐振频率影响很大.如何准确估计寄生电容的大小成为电感器设计的一个难题.采用Ansoft Q3D软件建立了叠层片式陶瓷电感器的3D静电场有限元模型,计算了各电极间的杂散电容,然后建立电感器的等效电容网络,列出节点电压方程并求解得到寄生电容.计算结果和测量结果基本一致.瓷...     

基于AD7150微位移电容传感器的研究

利用了集成芯片AD7150完成了对微位移电容传感器的电容采样。对AD7150芯片设计了相应的外接电路,为了增强电路的抗干扰能力,加入相应滤波电路;通过单片机模拟I2C通信方式来进行AD7150的读写控制。测量结果给出了10 pF以下不同标称电容值的电容,误差在2.5%以内。初步实验结果表明,当接入双叉电容传感器探头时,电容值随测量距离的增大而增加;在不同位移量下,传感器的灵敏度不同,距离越近,灵敏度越高,最大灵敏度为686 fF/mm,给出了不同情况下的灵敏度分布,并总结了影响电容传感器工作的电路要点。     

一种基于路灯补偿电容的电缆防盗系统设计

提出了一种通过测量照明线路补偿电容变化,来监测电缆是否被盗的新型电缆防盗报警系统设计方案。目前的照明路灯均具有较大的补偿电容,因此电缆上的电容将随电缆长度的变化而呈现规律性变化。新型系统正是基于以上原理测量电容值,通过AT89C51单片机计算分析精确定位出被盗位置,并通过语音芯片ISD25120,拨号芯片MT8888在电话上自动报警。在实际应用中,具有良好的报警效果。     

Comb Capacitor Structures for On-Chip Physical Uncloneable Function

Planar inter-digitated comb capacitor structures are an excellent tool for on-chip capacitance measurement and evaluation of properties of coating layers with varying composition. These comb structures are easily fabricated in a single step in the last metallization layer of a standard IC process. Capacitive coupling of these structures with a coating layer is modelled based on the electric field distribution to have a detailed understanding of contributing capacitance components. The coating composition is optimized to provide maximum spread in capacitance values of comb capacitor structures. This spread in measured capacitance values can be used to implement a physical uncloneable function (PUF). A PUF is a random function which can be evaluated only with the help of a physical system. We present an on-chip capacitive PUF for chip security and data storage in which the unlock key algorithm is generated from capacitors which are physically linked to the chip in an inseparable way. The strength of this key increases with the spread in capacitance values and measurement accuracy.      

基于S3F9488与CP2512的电子产品应用设计

运用电容触摸检测芯片CP2512与单片机S3F9488进行电路设计.触摸检测芯片CP2512通过检测电容的变化量来感知外界数据的变化,通过I2C协议把CP2512采集的数据送到S3F9488,S3F9488根据采集到的数据进行相应的功率控制.本文给出了CP2512与S3F9488的硬件设计图.该方案的设计可以使家电产品更加耐用、美观;能有效地提高产品的抗干扰能力,提升产品的品质.该电路的设计为家电产品提够了一种低成本解决方案,最终在电磁炉中得到了实现.     

一种应用于模拟卫星电视调谐器的单端晶体OSC

介绍了一种应用于模拟卫星电视调谐器的单端晶体OSC实现方法,本结构所有负载电容都集成在片内,片外只需连接晶体的单个管脚,片内所有电容都由MOS管栅电容实现,从而大大减小了芯片的面积,在0.18μm1P6MCMOS工艺下,整体版图面积只有0.023mm2.电路可实现外接晶体模式或外接激励模式自由切换,外接晶体时可在2-10M晶体下正常工作,振荡稳定产生轨到轨正弦波形,起振时间在1ms内,外接激励模式下可满足0.1～3.3V的正弦波输入.     

适合集成开关电容DC-DC变换器的浮地电容倍增器

针对在集成电路中制作大容量电容器的困难，提出了一种利用电流传输器提高集成电容器容量的方法，称之为连续可变浮地电容倍增器。分析了电容倍增的机理，建立了相应的关系式，在此基础上对用此浮地电容构成的一阶滤波器和开关电容DC-DC变换器进行了理论分析和PSPICE仿真。结果表明，利用电流传输器的阻抗变换作用，可使小容量的电容等效变换为较大容量的浮地电容，从而便于开关电容DC-DC变换器实现全单片集成。     

单一平面电容式漏水检测传感器的研究

针对北方地区冬季暖气管道漏水可能导致的大型设备机房或重要仪器损坏的问题,提出了一种用于管道漏水检测的单一平面电容式传感器的设计方案。该装置利用平面电容原理,检测水滴落在平面电容上时引起的电容变化,采用微电容测量电路将电容转换成频率,然后通过单片机处理后计算出电容值,通过和预先设定的阈值电容的比较来判断平板上是否漏水。经实际试验,该方案实施的平面电容式漏水检测传感器应用于管道漏水检测具有结构简单、成本便宜、性能可靠的特点。     

4096-Bit serial decoded multiphase serial-parallel-serial CCD memory

A new practical form of charge-coupled device (CCD) memory structure is described which achieves high storage density while providing low clock-line capacitance. In the new structure, the time-division multiplexing of multiphase concepts is replaced by the spatial multiplexing of a serial-parallel-serial (SPS) array. By using a ring counter to generate the multiphase clocking, a compact method of clock generation is described which allows the integration of multiphase drivers into the memory array. The improved density results from using a multiphase technique while the low clock-line capacitance stems from integrating the necessary drivers into the memory structure. The average bit density of the new structure including all necessary drivers exceeds that of previously discussed CCD memory structures when similar layout rules and gate electrode configurations are applied. A 4096-bit memory chip was built to fully demonstrate the new multiphase serial-parallel-serial storage (MSPS). The memory chip additionally uses serial decoding to increase the ratio of bit storage area to decoding circuitry area. The memory chip performed all memory functions of READ, WRITE, and REFRESH. The memory is organized into 16 separate 256-bit CCD shift registers. It is also found that interlacing is effective in increasing the average bit density in MSPS structures. The combination of high density and low drive capacitance makes the MSPS structure appear attractive for memory applications.     

Circuit implementations of the differential capacitance read scheme (DCRS) for ferroelectric random-access memories (FeRAM)

This paper presents two circuit implementations for the differential capacitance read scheme (DCRS) in ferroelectric random-access memories (FeRAM). Compared to the conventional read scheme, DCRS achieves a faster read access by activating the sense amplifiers immediately after a wordline is activated. By relying on the capacitance difference instead of the charge difference, DCRS avoids raising the highly capacitive platelines until after the read is complete. We have implemented this scheme in a 0.35-/spl mu/m CMOS+Ferro test chip that includes an array of 256 /spl times/ 32 2T-2C cells. The test chip measures an access time of 45 ns at a power supply of 3 V.     

基于Pcap01的电容式液位传感器系统设计

为精确测量汽车油箱油量,利用电容量随极板间介质变化的原理,设计了基于电容转数字芯片Pcap01的电容式液位传感器测量系统。采用柱形电容传感器等措施,减小了寄生和杂散电容,并通过Pcap01内部寄存器的设置,实现了数据校准。该系统在自行设计的实验平台上进行了多次实验,结果表明,系统具有良好的精度和线性度,并最终提出了电容式液位测量方案。     

Ultra-low-capacitance flip-chip-bonded GaInAs PIN photodetector for long-wavelength high-data-rate fibre-optic systems

A novel GaInAs substrate illuminated photodetector structure is reported for the 1.0?1.7 ?m wavelength range with capacitance as low as 0.02 pF, packaging stray capacitance below 0.02 pF, 97% quantum efficiency and subnanoampere leakage current. The device is rugged, epoxy-free, does not use an integral fibre pig-tail and wire bonding to the detector chip is not required.     

一种片内集成飞电容的自适应开关电容DC-DC

提出一种电容片内集成、高效率升压模式的DC-DC电源管理芯片,较普通结构相比,文中提出的电路结构具有6组2×,3组3×,2组4×升压模型共11种工作模式,并具有低纹波等优点。通过MIM电容与积累型NMOS电容串联的方式,提高单位面积容值,使得总电容面积大幅减小。采用SMIC 0.18μm CMOS工艺,利用Cadence工具对电路进行仿真验证,所提出自适应开关电容升压电路,在输出电压为3 V时,其效率最高可达到83.6%。在开关频率为20 MHz时,输入电压范围为1~1.8 V,所需总片内集成电容总面积为900 μm×900 μm,输出电压纹波＜40 mV     

VLSI互连线系统中的低介电常数材料与工艺研究

阐述了超大规模集成电路 ( VLSI)特征尺寸的减小及互连线层数增加引起的互连线电容增加的问题。具体总结了为提高 VLSI的速度而采用的低介电常数材料及其制备工艺 ,对在连线间形成空气间隙来降低线间电容的方法也进行了介绍。最后 ,展望了低介电常数材料在 VL SI互连线系统中的应用前景。     

A dynamically reconfigurable monolithic CMOS pressure sensor for smart fabric

This paper presents a mixed-signal system-on-chip (SOC) for sensing capacitance variations, enabling the creation of pressure-sensitive fabric. The chip is designed to sit in the corner of a smart fabric such as elastic foam overlaid with a matrix of conductive threads. When pressure is applied to the matrix, an image is created from measuring the differences in capacitance among the rows and columns of fibers patterned on the two opposite sides of the elastic substrate. The SOC approach provides the flexibility to accommodate for different fabric sizes and to perform image enhancement and on-chip data processing. The chip has been designed in a 0.35-/spl mu/m five-metal one-poly CMOS process working up to 40 MHz at 3.3 V of power supply, in a fully reconfigurable arrangement of 128 I/O lines. The core area is 32 mm/sup 2/.     

CCH型片式高压陶瓷电容器

MLCC制成小容量规格相对困难,且偶有破碎,可靠性差,用于制成圆片瓷介电容器的单层被银瓷片制成片式高压瓷介电容器以替代小容量的MLCC。开发设计了陶瓷芯片夹于上下两连体扁平引线中间并焊接后,再模塑环氧树脂封装,然后分割切开连体引线,使切开后的扁平引线平贴在外壳表面,得到了仍是用单层被银瓷片制成的片形高压瓷介电容器。该产品的小容量规格制造更容易,其可靠性高,适用于SMT。     

电容数字转换器AD7745的工作原理和应用

AD7745是AD公司生产的具有I2C总线接口的电容数字转换器。该转换器支持单端电容输入和差分式电容输入,同时在片内集成了温度传感器,可以用于代替系统中的温度传感器。该芯片广泛的应用于生化探测、压力探测、电压探测、杂质探测等领域。介绍AD7745的功能原理和工作模式,同时给出一种使用该芯片的实际应用。     

高稳定度和宽电源电压范围晶体振荡器芯片设计

基于0.6μm CMOS混合信号工艺设计了一款高稳定度、宽电源电压范围的晶体振荡器芯片。该芯片片内集成具有优异频率响应的振荡器电容和反馈电阻,只需外接石英晶体即可提供高稳定时钟源。测试结果表明:芯片最高工作频率可达40MHz;在振荡频率12MHz、负载电容15pF、电源电压从2.7V到5.5V变化时其频率随电源电压变化率小于1×10-6;电源电压为5V时芯片消耗总电流小于4mA。     

A cost-effective three axis CMOS accelerometer combining micromachining and digital technology

In this paper, a three axis accelerometer is successfully developed by a mixing-mode chip design using CMOS surface-micromachining technology. The chip consists of mass-spring, the analog core and the digital circuit. The vibration sensor is implemented with micro-spring to change the capacitance between two metals. The analog core detects the capacitance differential to the frequency shifting using an oscillator. The digital control is to compute the amount of acceleration to the form of digital bit. The chip can detect the acceleration to 140 g for x axis and y axis with 10-bit resolution, and from 110 g for z axis with 9 bits. The detected speed is about 4 k bits per second, for three-axis output in parallel. The chip size is about 1,400 × 1,400 um², when TSMC 0.18 um 1P6 M process is employed. This 3D accelerometer can directly connect to the digital interface with three serial-port output for the information of X, Y and Z axis.     

Ceramic capacitors for hybrid integrated circuits

Ruggedness, wide capacitance range, high volumetric efficiency, and relatively attractive cost have been the main reasons for the popularity of ceramic chip capacitors. Continuing improvements in most of these categories promise to keep the ceramic chip in its present position of prominence. This article considers multilayer, single-layer, and screened-on configurations. In addition, relationships between size, capacitance, and cost are covered for three common ceramic formulations (NPO, W5R, and Z5U).