共查询到19条相似文献,搜索用时 140 毫秒
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本文报道一种电容式闭环微加速度计的低噪声、开关电容CMOS接口电路。采用相同电极分时复用的方法,从而避免电容敏感与静电力反馈的馈通现象。并设计PID电路保证真空封装的高Q值加速度计的闭环稳定性及动态响应特性。整体电路结构只需单端放大器,传输门和电容。测试结果显示,接口电路工作在±5V条件下,整体微加速度计具有±3g满量程,非线性0.05%,800Hz带宽,刻度因子为1.2V/g,噪声密度为0.8μg/ 。芯片采用2um 双金属双多晶N阱CMOS工艺加工,芯片面积15.2 mm2。测试结果证明,本文电路达到高精度微加速度计系统设计要求,可以应用到地震监测、石油勘探等领域中。 相似文献
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单轴硅微加速度传感器的原理与电路设计 总被引:3,自引:0,他引:3
单轴硅微加速度传感器将敏感部分与外围信号调理电路集成在一起,成为一个完整的加速度测量系统。系统除供电电源外不需要任何外加因素,能够实现电路的无触摸启动工作。敏感部分采用差动电容式结构具有高灵敏度、宽量程、较低的非线性误差、外围电路简单等优点。外围电路将敏感输出信号相位调制后,通过解调输出。解调电路采用开关电容(SC)的形式,通过负反馈系统反馈电荷影响采样一积分幅度的思路,设计电路对有效信息解调。本文介绍单轴硅微加速度计敏感部分的原理与外围调理电路的设计思路。 相似文献
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为了提高MENS微加速度计的各种性能,完成了基于电容式微加速度计的过载传感器信号调理电路的设计。设计了基于Model 1221电容式微加速度计的信号调理电路,通过静态和动态调试,在频率响应范围内的带内不平度≤±3 dB,超出频率响应范围的带外衰减≥30 dB/oct。最后通过传感器主动校准系统对传感器进行标定测试,测试结果显示:理论值与实际值的误差很小,系统的准确度很高,而且在±15 gn的测量范围内的输出电压满足(0.2±0.2)V4.8±0.2V。 相似文献
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ADXL50和ADXL05是美国ADI公司生产的加速度计。它采用差电容作为敏感元件,用闭环反馈力平衡技术和完整的信号调理电路构成闭 环随动式加速度计。 相似文献
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Novel capacitive fingerprint sensor techniques are described. We propose a novel sensor cell architecture to obtain high sensitivity, wide output dynamic range, and contrast adjustment. For the architecture, three circuit techniques were developed. A sensing circuit with a differential charge-transfer amplifier enhances sensitivity while it suppresses the influence of the parasitic capacitance of the sensor plate. A wide output dynamic range, which is needed for high-resolution analog-to-digital (A/D) conversion, is achieved by transforming the sensed voltage to a time-variant signal. Finally, the sensing circuit includes an automatic contrast enhancement scheme that uses a variable-threshold Schmitt trigger circuit to distinguish the ridges and valleys of a fingerprint well. The characteristics of a test chip using the 0.5-μm CMOS process show a high sensitivity to less than 80 fF as the detected signal, while the variation of the output signal is suppressed to less than 3% at ±20% variation of the parasitic capacitance. The dynamic range of the time-variant signal is 70 μs, which is wide enough for A/D conversion. The automatic contrast enhancement scheme widens the time-variant signal 100 μs more. A single-chip fingerprint sensor/identifier LSI using the proposed sensing circuit scheme confirms the scheme's effectiveness 相似文献
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We show that the pinched hysteresis behavior observed in a voltage-controlled resistor with state-feedback self-control can be attributed to the current flowing in the parasitic capacitance holding the voltage across this resistor. A mathematical model describing this circuit structure is derived and validated numerically. To provide experimental evidence of this proposal, a circuit representing a voltage-controlled resistor is placed in parallel with a capacitor and then the current in this capacitor, which is proportional to the derivative of the applied voltage, is sensed, converted into a voltage and used to control the resistance value. This leads to the appearance of a pinched hysteresis loop as theoretically predicted. This work provides further insight into the origin of this behavior in fabricated solid-state devices that can be shown to follow the proposed circuit structure. 相似文献
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基于充放电原理实现的微电容测量电路 总被引:1,自引:0,他引:1
具有抗分布电容以及简单实用等特性的充放电电路是目前微电容测量中广泛采用的一种测量电路。本文对基于充放电原理的微电容测量电路进行了深入研究,并介绍一种基于充放电原理的实用电路。 相似文献
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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。 相似文献
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电感位移传感器被广泛应用于微小位移量检测中,但在一些工程中现有传感器的测量精度和灵敏度达不到测量要求。针对这一问题,对传感器前段信号处理电路进行改进,在传感器上下线圈并联电容形成LC电路,利用LC电路谐振效应改善电路的性能,以提高信号源头的灵敏度;采用Multisim软件对半桥和全桥电路在并联不同大小的电容后的性能进行仿真,并用Matlab对生成的曲线进行最小二乘拟合,比较得出使电路性能最优的电容值和并联方法。结果表明在损失微小线性度的情况下可将灵敏度提高一倍。 相似文献
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Bogusaw Wisz 《Microelectronics Reliability》2008,48(5):724-733
This paper presents the analytical method of capacitance calculation for the hybrid circuit. The analyzed example of planar conductive paths, being a system of typical spatial configuration, is a part of research that is to develop a general, universal mathematic model to calculate parasite capacitances in hybrid structures. In general, this leads to solve the 3D boundary problem. The Fourier’s integral transformation has been used in order to determine the potential satisfying the Laplace equation.
Resulting from here the equation system of electric charge distribution is being solved numerically by using the collocation method. On this basis the capacitance between conducting paths is calculated and experimentally verified. 相似文献
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随着科技的发展,LED的性能也得到了大幅提高,应用也越来越广泛,对驱动电路的要求也越来越高。这里主要阐述了当前应用较广泛的电容降压驱动电路的工作原理和用途。电容降压驱动电路是一类新型的LED驱动电路,具有体积小、价格低、安装方便等优点,具有广阔的应用前景。介绍了多种LED电容降压驱动电路及不同的用途。 相似文献