改善放大器电路电源抑制比的方法

在实际应用电路时,噪声及波动经常不知不觉会引入到供电电压中,从而影响输出端电压。为使电路稳定,需消除或抑制所产生的噪声。文中讨论了3种改善放大器电路电源抑制比（PSRR）的方法：共源共栅方法、反馈技术、设计附加的能够减小电源对输出端电压增益影响的电路。通过3种技术的仿真数据输对比,其能维持较高的增益值,对有级联放大器的...     

一种具有高电源抑制比的带隙基准电压源

根据带隙基准电压源理论,在传统CMOS带隙电压源电路结构的基础上,采用曲率补偿技术,对一阶温度补偿电路进行高阶补偿,获得了一种结构简单,电源抑制比和温度系数等性能都较好的带隙电压基准源.该电路采用CSMC 0.5 μm标准CMOS工艺实现,用Spectre进行仿真.结果表明,在3.3 V电源电压下,在-30 ℃～125 ℃范围内,温度系数为3.2×10-6 /℃;在27 ℃下,10 Hz时电源抑制比(PSRR)高达118 dB,1 kHz时(PSRR)达到86 dB.     

一种高电源抑制比带隙基准电压源的设计

设计了一种基于反馈电路的基准电压电路。通过正、负两路反馈使输出基准电压获得了高交流电源抑制比(PSRR),为后续电路提供了稳定的电压。采用NPN型三极管,有效消除了运放失调电压对带隙基准电压精度产生的影响,并对电路进行温度补偿,大大减小了温漂。整个电路采用0.35μm CMOS工艺实现,通过spectre仿真软件在室温27℃、工作电压为4 V的条件下进行仿真,带隙基准的输出电压为1.28 V,静态电流为2μA,在-20~80℃范围内其温度系数约为18.9×10-6/℃,交流PSRR约为-107 dB。     

一种-100 dB电源抑制比的非带隙基准电压源

该文提出一种非带隙基准电路,通过一个带超级源极跟随器的预调制电路提供一个稳定的电压,为基准核心电路供电。超级源极跟随器通过降低基准核心电路电源端的对地阻抗,有效提高了基准电路的电源抑制能力。该基准电路采用0.35 m CMOS 工艺设计并流片,测试结果表明,该电路的工作电源电压为1.8~5 V,静态电流约为13 A。低频处电源抑制比(PSRR)约等于-100 dB,在小于1 kHz频率范围内PSRR均优于-93 dB。并且其片上面积仅为0.013 mm2。     

一种低噪声高电源抑制比CMOS低压差线性稳压器

提出了一款基于标准0.18μm CMOS工艺的低噪声高电源抑制比(PSRR)CMOS低压差线性稳压器(LDO),其中包括了带隙基准电路。对LDO和带隙基准电路的噪声和电源抑制进行了建模分析,并得出了电路设计原则。根据设计原则使用两级误差放大器实现了低噪声高电源抑制性能,并且通过合理的频率补偿保证了电路稳定。测试结果显示,LDO输出在-40¹20℃温度范围内的温度系数约为48×10-6/℃;在1120℃温度范围内的温度系数约为48×10-6/℃;在1¹00kHz频率范围内输出噪声电压约为37.3μV;在1kHz和1MHz处的PSRR分别大于60dB和35dB;芯片总面积约为0.27mm2,无负载电流约为169μA。     

一种高带宽、高电源抑制比的跨阻放大器

光电探测器是激光雷达的核心器件,通常由雪崩光电二极管(APD)阵列和相应的读出电路组成。跨阻放大器是读出电路的关键部分,其性能在很大程度上决定光电探测组件的性能。基于0.18μm CMOS工艺,针对大输入电容线性APD阵列的应用,设计了一种高增益、高带宽、高电源抑制比的跨阻放大器。基于无源反馈和有源前馈的补偿方式拓展了跨阻放大器带宽,同时实现了高增益和高带宽;设计了具有高电源抑制比的片上无电容低压差稳压器,提高了跨阻放大器的稳定性。仿真结果表明:跨阻增益为104.7 dB·Ω,带宽为198.8 MHz,等效输入噪声电流为3.65 pA·Hz~(-1/2),低频电源抑制比为-57.8 dB,全带宽范围内电源抑制比低于-10.6 dB。     

一种高电源抑制比的全MOS电压基准源设计

基于MOS管在亚阈值区、线性区和饱和区的不同导电特性,采用TSMC 0.18 μm CMOS工艺,设计了一种全MOS结构的电压基准源。为了改进核心电路,通过设计并优化预抑制电路,使整个电路实现了高电源电压抑制比的输出电压。对电路进行仿真,当电源电压大于1.5 V时,电路进入正常工作状态;在1.8 V电源电压下,-20 ℃~120 ℃范围内,温度系数为1.04×10-5/℃,该电压基准源的输出电压为0.688 V;低频时,电源电压抑制比达到-159.3 dB,在1 MHz时电源电压抑制比为-66.8 dB,功耗小于9.83 μW。该电压基准源能应用于高电源电压抑制比、低功耗的LDO电路中。     

基于MEMS的压阻式超声传感器的设计与测试

A kind of piezoresistive ultrasonic sensor based on MEMS is proposed,which is composed of a membrane and two side beams.A simplified mathematical model has been established to analyze the mechanical properties of the sensor.On the basis of the theoretical analysis,the structural size and layout location of the piezoresistors are determined by simulation analysis.The boron-implanted piezoresistors located on membrane and side beams form a Wheatstone bridge to detect acoustic signal.The membrane-beam microstructure is fabricated integrally by MEMS manufacturing technology.Finally,this paper presents the experimental characterization of the ultrasonic sensor,validating the theoretical model used and the simulated model.The sensitivity reaches -116.2 dB(0 dB reference = 1 V/μbar,31 kHz),resonant frequency is 39.6 kHz,direction angle is 55°.     

MEMS based low cost piezoresistive microcantilever force sensor and sensor module

In the present work, we report fabrication and characterization of a low-cost MEMS based piezoresistive micro-force sensor with SU-8 tip using laboratory made silicon-on-insulator (SOI) substrate. To prepare SOI wafer, silicon film (0.8 µm thick) was deposited on an oxidized silicon wafer using RF magnetron sputtering technique. The films were deposited in argon (Ar) ambient without external substrate heating. The material characteristics of the sputtered deposited silicon film and silicon film annealed at different temperatures (400–1050 °C) were studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The residual stress of the films was measured as a function of annealing temperature. The stress of the as-deposited films was observed to be compressive and annealing the film above 1050 °C resulted in a tensile stress. The stress of the film decreased gradually with increase in annealing temperature. The fabricated cantilevers were 130 μm in length, 40 μm wide and 1.0 μm thick. A series of force–displacement curves were obtained using fabricated microcantilever with commercial AFM setup and the data were analyzed to get the spring constant and the sensitivity of the fabricated microcantilever. The measured spring constant and sensitivity of the sensor was 0.1488 N/m and 2.7 mV/N. The microcantilever force sensor was integrated with an electronic module that detects the change in resistance of the sensor with respect to the applied force and displays it on the computer screen.     

一种高电源抑制比LDO

采用0.18 μm CMOS工艺,设计了一种低压差线性稳压器(LDO)。分析了传统LDO在重载高频下电源抑制比(PSR)的缺陷,提出一种带有多级缓冲PSR提升结构的LDO。采用创新的PSR增强结构,使得PSR增强效果与其负载电流成弱相关,从而保证LDO在宽负载范围内具有优秀的高频PSR增强效果。仿真结果表明,负载电流为300 mA时,低频下LDO的PSR为-68 dB,频率为10 MHz时LDO的PSR可达－50 dB。     

基于MEMS的压阻式三轴加速度计的设计与测试

随着微机电(MEMS)产业的兴起,加速度计正在向微型化,集成化,高可靠性,高灵敏度的方向发展,具有广泛的军事和民用前景。在此提出了一种压敏电阻完全对称分布的“8梁—质量块”结构的硅微压阻式三轴加速度计,与传统的单悬臂梁结构或悬臂梁—质量块结构相比,这种结构具有更高的灵敏度和更小的轴间耦合度。介绍了采用ANSYS软件进行结构分析的过程,给出了三轴加速度计敏感单元的制作工艺流程。通过对加速度计的静态测试得出X、Y、Z轴的灵敏度分别为SX=48*10-6V/g, SY=54*10-6V/g, SZ=217*10-6V/g,非线性度分别为0.4%,0.6%,0.4% 。     

MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.     

低压降CMOS稳压器的电源噪声抑制分析

通过对低压降CMOS稳压器工作原理的分析,给出了一种频域分析模型。基于此模型,对低压降稳压器的电源噪声抑制进行了分析和研究,得到了低压降稳压器在频域的传递函数;依据此传递函数,给出了改善电源噪声抑制的方法。此外,给出了几种有效提高电源噪声抑制的方法和电路。     

Temperature stability of a piezoresistive MEMS resonator including self-heating

Temperature stability of a piezoresistive 1.5 μm thin SOI resonator at 74 MHz is presented. As compared to capacitive resonators the self-heating due to the bias current causes a further decrease of the resonator frequency, in addition to the well-known dependency on ambient temperature. The interpretation of the resonance frequency as a device temperature is not obvious anymore under self-heating due to the inhomogeneous temperature distribution.     

压阻式压力传感器信号噪声比改进研究

通过介绍压阻式压力传感器工作原理,分析噪声的主要起源,提出了针对不同噪声源(电噪声和外界电荷引起的非本征噪声)的解决措施,为将来针对高SNR的压力传感器设计提供参考依据。     

Power Supply Rejection for RF Amplifiers: Theory and Measurements

Supply noise is a significant problem in RF systems where it can mix with RF signals, degrading signal/noise ratios and potentially causing violation of spectral masks. This paper presents an analysis of the supply rejection properties of RF amplifiers. We extend a conventional Volterra-series formulation to treat multiport systems and use it to describe the mixing products between power supply noise and the RF carrier. It is shown that a multiport Volterra formulation can be used to treat weak nonlinearities in the system and that the nonsymmetric cross terms accurately predict low-order mixing phenomenon. We demonstrate the validity of our hand analysis through the design and fabrication of a power amplifier in 180-nm CMOS, operating between 900 MHz-2.4 GHz with a maximum output power of 15 dBm. Spectral regrowth of single-tone and EDGE modulation waveforms is shown to match within 1-3 dB across frequency and input signal power. Importantly, this analysis provides insight into the circuit-level mechanisms for susceptibility to power supply noise and can help designers improve the power supply rejection ratio robustness of system-on-chip wireless blocks and transmitter architectures.     

MEMS压阻式超声传感器阵列的设计与测试

The design,fabrication and packaging of a type of MEMS piezoresistive ultrasonic transducer array are introduced.The consistency of the resonance frequency and the sensitivity of the array are tested.Moreover,we detect the directivity and the multi-target identification ability of the array.The results of the consistency of the resonance frequency and the sensitivity show that there is a gap between the practical and theoretical results.This paper analyzes this problem in detail and points out the direction of improvement.As for the directivity,the actual result is consistent with the theoretical one.The results of multiple target distinguishing tests demonstrate that the smallest resolution angle of the array is 5.72°when the distance between the sensor array and measured objects is 2 m.     

一种宽输入范围高电源抑制比的带隙基准源

基于CSMC 0.5 μm BCD工艺,设计了一种具有高电源抑制比的带隙基准电路。此电路可以在较宽电源电压(4~36 V)范围内实现较小的温度系数变化,－40 ℃~125 ℃范围内的温度系数为8.93×10-6/℃~9.02×10-6/℃。通过将基准参考点设置于负反馈环路中,能够有效地提高基准电路的电源抑制性能。当电源电压为4~36 V时,电源抑制比分别为－132~－98 dB@dc,－54.7～－55.5 dB@1 MHz,线性调整率为0.009%/V,满足DC-DC转换器的应用需求。     

开关电源的电磁兼容分析及改进

分析了开关电源电磁干扰产生的主要原因,以电磁兼容性的三要素为基础从理论上对开关电源电磁干扰进行了分析,提出相应的改进措施,并介绍了抑制电磁干扰的主要措施——滤波技术,最后对滤波器的结构、工作原理和选用方法作了分析。     

基于新型启动电路的高电源抑制带隙基准源

设计了一种基于新型启动电路的高电源抑制(PSR)的带隙基准电压源。启动电路可以在300ns的时间内使电路进入工作状态,同时可在10ns的时间内完全关断电路。可控的启动电路增加了电路使用的灵活性。本基准电路基于新加坡Chartered0.25μmN阱CMOS工艺实现,已应用于射频调谐器当中。测试结果表明,基准电压源在低频段的电源抑制PSR≈123dB,高频段PSR>50dB,电路采用一阶温度补偿技术,在0～100℃的温度范围内输出基准电压的温度系数(TC)约为12ppm/℃。