一种无运放低压低功耗CMOS带隙基准电压源的设计

采用无运放电路结构,通过改进反馈环路和调整电阻的方法,设计了一种低电压低功耗的带隙基准电压源.相比传统有运放结构,电路芯片面积更小和具有更低的电流损耗,并且大部分电流损耗都用于产生输出电压.基于CSMC 0.5 μmCMOS工艺对所研制带隙基准电压源进行流片,测试结果表明,当电源电压大于0.85 V时,能够产生稳定的输...     

一种新型的电压温度双参量光纤传感器

提出了一种电压温度双参量光纤传感器.在理论上分析了从一个敏感晶体上分离出温度、电压两种信息的可能性:石英晶体作为敏感元件.通过合理安排传感头中各部件.传感器同时输出两路信号:一路是包含Pockels效应的电压信号;一路是石英晶体旋光效应的信号.由于旋光效应与温度有关.这路信号用来反映传感头光路上的温度信息.实验获得理论所预期的结果.从而只使用一个传感头就可以同时测量电压与温度.给出了实验装置.结果显示在90℃温度范围内电压的精度可达0.5%.温度的精度为±1℃.     

高精度低噪声基准电压源的设计

利用反向带隙电压原理,采用基于CMOS阈值电压的自偏置共源共栅电流镜技术,设计了一种低压低噪声基准电压源.该电压基准源没有外加滤波电容的情况下,通过双极型晶体管大的输出阻抗特性,实现了更低的噪声输出,提高了输出电压的精度.Hspice仿真结果表明,在0.95V电源电压下,输出基准电压为233.9 mV,温度系数为7.6...     

Practical Implementation of a High-Frequency Current-Sense Technique for VRM

To track the inductor current in high-frequency dc/dc converters is not effortless, particularly when high output currents and low output voltages are demanded by the load. This paper proposes a simple technique to obtain a good accuracy in the inductor current measurement in voltage regulator module (VRM) applications. The main idea is to obtain an equivalent voltage image which can be used for the high-frequency pulsewidth modulation controller to generate the converter control law. This strategy of measurement is generic, and it has been previously validated by simulations. Afterward, some experimental results are obtained by using several prototypes of dc/dc converters delivering a very low output voltage and owning several loads from 10-mA to 100-A currents. This wide range covers the power requirements of portable and embedded VRM applications. Moreover, this sense technique has also been validated in a digital high-frequency current-mode-controlled dc/dc converter.      

A novel embedded soft-start circuit for SOC power supply

To improve the power sequencing performance of the system-on-a-chip (SOC),a novel embedded soft-start circuit is presented.A seamless soft-start reference voltage is obtained with 7 bits DAC,which can not only restrain the turning point overshoot,but also improve the output accuracy and the poor loading capability,reduce the pin number and save PCB area.The whole DC-DC converter has been fabricated in a 0.35 μm CMOS process.The measurement results show that the chip starts up successfully with 250 μs soft-start time under conditions of 400 kHz switchingfrequency,2.5 V DC-DC output and 1.8 V LDO output.Stable operation after soft-start is also shown.     

利用导通电压降监测SLD的输出光功率

由于传统的光功率采集仪精度不高,在实验中无法明显地显示出光功率在短期内的变化,而采集电压的数据采集系统可以很好地解决这个问题。在分析1310 nm超辐射发光二极管(Super Luminescent Diode,SLD)光源的工作原理的基础上,设计了一种在恒温条件下控制驱动电流来使SLD稳定工作的驱动电路,进行了理论分析和实验验证,给出了利用SLD电压降监测输出光功率的新方法,取得了真实可靠的实验数据。通过SLD光源的驱动实验得出输出光功率与驱动电流和SLD两端电压降的相关关系,结果表明,输出光功率与电流具有良好的线性关系,与电压具有良好的正相关指数关系。利用采集电压降监测SLD的输出光功率,大大提高了测试精度和数据分辨率,同时为SLD退化寿命试验提供了新的电学参数。     

Nonlinear characterization of GaN HEMT

DC I-V output, small signal and an extensive large signal characterization (load-pull measurements) of a GaN HEMT on a SiC substrate with different gate widths of 100μm and 1 mm have been carried out. From the small signal data, it has been found that the cutoff frequencies increase with gate width varying from 100μm to 1 mm, owing to the reduced contribution of the parasitic effect. The devices investigated with different gate widths are enough to work in the C band and X band. The large signal measurements include the load-pull measurements and power sweep measurements at the C band (5.5 GHz) and X band (8 GHz). When biasing the gate voltage in class AB and selecting the source impedance, the optimum load impedances seen from the device for output power and PAE were localized in the load-pull map. The results of a power sweep at an 8 GHz biased various drain voltage demonstrate that a GaN HEMT on a SiC substrate has good thermal conductivity and a high breakdown voltage, and the CW power density of 10.16 W/mm was obtained. From the results of the power sweep measurement at 5.5 GHz with different gate widths, the actual scaling rules and heat effect on the large periphery device were analyzed, although the effects are not serious.The measurement results and analyses prove that a GaN HEMT on a SiC substrate is an ideal candidate for high-power amplifier design.     

A new online state-of-charge estimation and monitoring system for sealed lead-acid batteries in Telecommunication power supplies

This paper presents a new, online, battery state-of-charge estimation and monitoring system for both the discharge and charge periods of sealed lead-acid batteries, commonly used in telecommunication power systems as backup power supplies. The proposed monitoring system is based on discharge time versus discharge rate data given in manufacturers' data sheets, and coulometric measurements, without the need for any battery voltage measurement under open-circuit conditions. The corresponding battery management system can perform both the online monitoring and battery charging tasks by the use of the same low-cost 8-bit microcontroller. Battery state-of-charge monitoring tests have been carried out under both constant and dynamic load conditions and for alternate charge-discharge cycles of lead-acid batteries of different capacities, and for different operating temperatures. The test results have shown that a very good accuracy (better than 3%-4%) in the estimation of available capacity is obtained for various charge-discharge strategies corresponding to practical operating conditions. Changes in battery characteristics which occur due to aging are also taken into account by estimating the actual capacity of the battery and adopting the corresponding recharacterization of the aged cells automatically.     

基于双波段对数比放大的热风炉拱顶测温系统

为了解决传统热风炉拱顶测温系统存在的维护难度大、发射率难以确定等问题,采用了双波段对数比放大测温方法,并对其进行了理论推导和实验验证。结果表明,在设定温度不变的前提下,该方法的测量结果与随着时间改变的温度几乎保持一致;并验证了设定温度与测量温度之间的关系,本系统测温误差绝对值在6℃以内,测量精度高;也验证了LOG112输出电压与真实温度的倒数呈线性关系,这与理论推导一致。该研究将辐射测温与对数比放大技术相结合,对于解决现存问题及提高拱顶测温精度具有重要意义。     

Steady-state operation of a high-voltage multiresonant converter in a high-temperature environment

Often scientific instruments on exploratory satellites are used to collect cosmic particles. These instruments, such as the Faraday cup, require a high-voltage regulated power source. On the proposed solar probe satellite there will be instruments which will collect cosmic particles close to the sun. Naturally temperature effects on the voltage regulator are a concern. Specifically power dissipation within the regulator must stay within stringent guidelines. The high-voltage regulator circuit is a resonant flyback topology with a dissipative series switch whose on resistance controls the output voltage level. The extreme temperatures in space will change the inductance of the flyback transformer which will affect the output voltage. State space analysis techniques are used to determine how the value of the transformer inductance and capacitance in the flyback converter affects the output voltage and consequently the power dissipated by the transformer and the switch. The accuracy of the analysis is verified by comparing results with those obtained from an experimental circuit. The results can then be used to help the designer chose nominal capacitance and inductance values that will work over the temperature range of interest.     

Digital Control of Single-Phase Power Factor Preregulators Based on Current and Voltage Sensing at Switch Terminals

This paper proposes a fully digital control of boost power factor preregulators (PFPs) with input voltage estimation that is suitable for smart-power integration. The proposed solution features a minimum pin count by avoiding input voltage sensing for the generation of the internal current reference and by sensing the output voltage through the direct sampling of the voltage across the power switch during its off interval at the line voltage peak. The control algorithm requires the estimation of the rectified input voltage, that is simply done by exploiting the integral part of the current loop proportional–integral regulator, and a phase-looked-loop (PLL) synchronization with the estimated line frequency for sampling the output voltage and rejecting the low-frequency output voltage ripple. The provisions needed to ensure correct output voltage sensing, even during transient and light-load conditions, are also discussed. Experimental results on a single-phase boost PFP show the properties of the proposed approach.     

双端磁耦合式压电振动俘能器结构设计

现有的非线性压电俘能器的输出功率提升主要通过改变俘能器的结构或引入非线性元素,但这些方法在提高俘能结构的输出功率,拓宽俘能器的俘能频带方面能力受限。该文设计了一种双端磁耦合式悬臂梁结构压电俘能结构,在利用永磁体引入非线性元素的基础上优化俘能结构,进一步提高系统的输出电压,拓宽俘能频带。通过将悬臂梁俘能结构等效为复杂边界条件的悬臂梁,推导磁耦合式悬臂梁结构的工作状态方程,并得到磁耦合式悬臂梁俘能结构的输出电压与永磁铁间距的关系,并通过实验测试进行验证。结果表明,在永磁体间距为5mm时,压电俘能结构获得最大的输出功率,在最佳的永磁铁间距和负载电阻下,双端压电磁耦合式悬臂梁的输出功率可达传统悬臂梁式压电俘能结构的1.5倍,谐振频率下降约7Hz。     

Harvesting vibration energy using piezoelectric material: Modeling,simulation and experimental verifications

Piezoelectric materials produce electrical charges when subjected to dynamic strain. These materials can be used to capture and store vibrational energy which later can be used to power up small devices. This paper presents an analytical estimation of voltage production of piezoelectric cantilever beam when subjected to base excitation, with and without attached proof masses. The beam is modeled using Euler–Bernoulli, also known as thin beam theory. As such, the model obtained here is applicable for micro- and nano-beams. The frequency response function (FRF) that relates the output voltage and transverse acceleration is identified for multi-mode vibration. These analytical predictions are then compared with experimental results and good agreement is obtained.     

基于正交定向耦合器组合的微波功率测量方法

定向耦合器广泛应用于微波系统的功率测量.但定向耦合器的方向隔离度有限,两个方向的耦合输出信号存在一定程度地串扰,影响功率测量的准确性.为了解决这一问题,本文提出一种正交耦合测量方法.该方法采用一对相位差为90°的定向耦合器同时测量功率,通过对测量结果的计算处理,可消除方向串扰的影响.推导了正反向传输功率与正交耦合器组合功率测量值的关系,分析了正交偏差所产生的误差.为了确定耦合器的正交状态,提出了一种准确测量两个定向耦合器之间相位差的方法.实测表明正交耦合方法可有效提高功率和驻波比测量的准确性.     

大气压脉冲氮分子激光器研究

工作于1个大气压下的氮分子激光器,由于不需要抽真空系统,以及能从小的激光腔体中给出较大的功率输出而受到人们的重视。此外,它的光脉冲宽度很窄(小于1毫微秒),为泵浦染料、进行荧光寿命测定、超高速照相、光化学反应等的研究提供了一个合适的,波长在3371埃的脉冲紫外激光光源。近年来,在改进大气压氮分子激光器的器件结构、小型化、提高重复频率和输出功率等方面已发表了一些文章。本文报导我们在大气压氮分子激光器方面进行的一系列实验研究,为设计稳定可靠、简单易行、小型方便的大气压氮分子激光器提供参考。     

移动电源综合性能测量技术分析

通过对移动电源重要性能及参数的分析,提出了针对每项性能及参数的测量方法?采用这些测量方法可以达到对移动电源综合性能的评估目的?其中电性能参数中输出电压?放电性能?转换效率的测量,可以分析得到移动电源输出电压值?输出容量值能否满足要求?安全性能中过充电保护?过放电保护?短路保护?发热?防火的测量来检查移动电源能否符合安全要求,以保证使用人员的安全?环境适应性和电磁兼容性参数的测量用以保证移动电源处于非常态环境时的性能能否满足要求?     

输出功率连续线性可调的微波干燥系统设计

针对目前功率可调微波系统存在的问题,设计了一种输出功率连续线性可调的微波干燥系统。通过反馈控制电路调节磁控管谐振腔极板的电压,从而实现微波输出功率的连续线性可调。该系统主要包括独立磁控管灯丝供电、电压-功率非线性校正以及反馈控制的磁控管谐振腔供电电路等3 部分构成。通过实验验证了输入所需的功率密度和实际输出的功率密度之间直线度较好,确定系数R² 为0.9709。     

数字化直流电流互感器二次激励电源研究

为了提高直流电流互感器的测量精度,研究出一种能根据采样电流大小调整激励电源输出电压的交流稳压电源系统。该系统以TMS320LF2407型DSP为核心,采用DSP技术和步进电机控制技术实现高精度直流电流互感器二次激励电源设计,采用小信号直流电流传感器及A／D转换电路解决二次激励电源的非线性补偿问题。实验结果表明：该系统输出交流电压幅度稳定度可达0．5％,完全满足直流电流互感器实际使用要求。     

DFIG-Based Power Generation System With UPS Function for Variable-Speed Applications

The power generation system with a doubly fed induction generator (DFIG), which can be used as an autonomous power system after the loss of mains in a distributed generation network, is described. After the mains outage, a fixed frequency and an amplitude of the output voltage are obtained, despite the variable rotor speed. For this reason, it can be successfully applied in the variable-speed wind turbines, adjustable speed water plants, or diesel engines. Moreover, the stand-alone operation of DFIG is useful in a flywheel-based high-energy rotary uninterruptible power supply system. An output voltage is controlled directly by the synchronization of an actual voltage vector with the reference vector represented in a synchronously rotating polar frame. The rotor current angular speed is obtained as a result of vectorial phase-locked loop operation. Any sensors or estimators of the rotor speed or position are unnecessary. Both amplitude and angle control loops are linear. The use of stand-alone operation in grid-connected systems requires mains outage detection. Also, the grid voltage recovery requires a method of synchronization and soft connection of a generator to the grid. The proposed methods of output voltage control, synchronization, and detection of mains loss were tested in a laboratory system.      

视场超出目标的红外测温误差修正方法研究

为解决红外测温系统超出有效测温距离导致的测温精度下降问题,从红外热辐射理论出发,提出了一种视场超出目标辐射表面积的红外测温系统误差修正方法。通过计算全视场范围内的辐射照度,获得了对应的红外测温系统电压响应值。依据电压响应值与温度之间的关系,并充分考虑物体表面形貌特征,去除全视场范围内背景温度的影响,得到目标体的表面真实温度值。相对于以往的修正方法,该方法能很好地修正有效测温距离外的物体表面温度,结果与被测物体实际温度更为相近。因此,该方法极大地增强了红外测温系统的工业现场适用性。