电流型PWM DC-DC升压转换器的稳定性分析与实现

文章先对影响电流型DC-DC升压转换器电路的系统稳定性的因素进行分析，然后在电路设计实现上提出了具体的改进办法：在误差放大器模块增加频率补偿电路来消除放大器反馈环路可能存在的振荡现象：采用斜坡补偿电路来增强反馈电流环路的稳定；为了提高电压反馈环路的稳定性，创新提出在芯片外部增加COMP管脚。内部增加环路补偿电路；输入管脚增加旁路电容以减少噪声；输出管脚增加旁路电容以增强芯片反馈系统的稳定性;通过采取这些措施，保证了芯片电路的的稳定性能，并极大的提高了输出电压的精度，设计取得了很大成功。     

基于gyrator结构复数滤波器稳定性分析

分析了滤波器电路振荡的可能以及产生振荡的原因,对其中各个环路都进行了稳定性分析.为了保证各个共模环路的稳定性,最粗略的估计要求跨导单元的共模增益小于0.6.在此稳定性分析的基础上,设计了复数滤波器电路,并给出了仿真和测试结果.     

一种新颖的过热保护电路的设计

提出了一种新颖的过热保护电路--热调节电路,该电路将芯片耗散功率产生的温度变化置于一个闭环控制系统中,形成温度负反馈,实现芯片在需要过热保护时的恒温控制,保证芯片在无过热危险前提下的输出功率最大化.芯片采用SMIC 0.13μm CMOS Logic工艺模型,测试结果表明,热调节电路在出现过热情况时可使芯片内部温度恒定在105℃.     

一种通用宽带FM解调电路的设计

实现了一款可用于卫星接收系统中频段电视信号的解调电路.该芯片的设计基于BiC-MOS工艺.采用5 V电源电压供电,利用单片锁相环(PLL)实现宽带FM解调,外围器件只包括本地振荡维持网络和环路反馈元件,PLL工作频率可达800 MHz.芯片内部还集成了自动增益控制(AGC)、模拟自动频率控制(AFC)模块.该芯片具有较高的信号接收灵敏度.     

低相位噪声和低参考杂散CMOS锁相环的优化设计与实现

基于Simulink建立的CMOS电荷泵锁相环的动态模型,对电荷泵锁相环的环路参数与环路稳定性的关系进行了仿真与分析,根据分析结果确定了4GHz锁相环的环路参数,并围绕低相位噪声和低参考杂散设计了锁相环各单元电路结构。该锁相环采用SMIC 0.18m CMOS工艺进行了流片,芯片面积为675μm×700μm。测试的VCO在控制电压为0.3~1.5V时,振荡频率为3.98~4.3GHz;当分频比为1036,参考信号频率为4MHz,锁定状态下锁相环的相位噪声测量值为-120.5dBc/Hz@100kHz及-127.5dBc/Hz@1MHz;电路参考杂散约为-70dB,整体性能优良。     

大功率半导体激光器调制特性的实验研究

设计了一种带有调制输入接口及恒电流、恒功率、恒温控制的光源系统,着重对其低频调制特性进行了实验研究.通过引入负反馈及自动温度控制技术,从外部电路角度改善了半导体激光器的调制输出特性,有效抑制了驰豫振荡,优化了激光二极管(LD)的调制输出参数.     

一款用于LED驱动芯片的CMOS振荡器

研究一款适用于LED驱动芯片的CMOS振荡器电路.其工作原理是在环路振荡器中加入恒定电流源,以恒定电流对电容充电、MOS管对电容快速放电以产生锯齿波再经锁存器产生周期脉冲信号.与传统的环路振荡器相比,此电路的优点是振荡频率精确、波形稳定,振荡频率在一定的电源电压范围内对电源电压变化不敏感.此振荡器电路已经成功应用于一款LED驱动芯片中.     

集成加热恒温检波电路及温度稳定系统设计

本文介绍采用一种新颖的加热、检温方式,设计研制集成加热恒温检波电路.详细地给出了电路及其集成加热芯片的设计,并对不同封装形式的加热功率和芯片温度分布作了对比分析.最后给出了电路布局与研制工艺方案.     

应用于5GHz WLAN的单片CMOS频率综合器

采用中芯国际(SMIC)的0.18μm混合信号与射频1P6MCMOS工艺实现了WLAN802.11a收发机的锁相环型频率综合器,它集成了压控振荡器、双模预分频器、鉴频鉴相器、电荷泵、各种数字计数器、数字寄存器和控制等电路。基于环路的线性模型,对环路参数的优化设计及环路性能进行了深入的讨论。流片后测试结果表明,该频率综合器的锁定范围为4096～4288MHz,在振荡频率为4.154GHz时,偏离中心频率1MHz处的相位噪声可以达到-117dBc/Hz,输出功率约为-3dBm。芯片面积为0.675mm×0.700mm。采用1.8V的电源供电,核心电路功耗约为24mW。     

电流模控制高效同步DC-DC芯片设计

采用0.18μm工艺设计一款同步高效降压型DC-DC电源芯片.为了实现快速响应、提高转换效率以及减小芯片面积的目的,该芯片采用电流模控制,应用电压外环与电流内环双环控制方式实现电路的快速响应和系统环路的稳定性.带补偿的电流检测电路能有效提高采样速度与精度.采用死区缓冲技术设计死区时间可调的缓冲器,并对误差放大器中补偿网...     

一种高精度数控直流源的设计

设计采用硬件闭环负反馈方案实现恒流控制,用两路8位D/A组成一路16位D/A转换电路实现高精度输出电流设定。单片机89C52主要用于控制D/A电路产生稳定的控制电压、控制A/D电路完成电流测量,同时还兼管键盘、显示等人机接口。测试表明,采用该设计的数控直流源具有精度高、响应快、范围宽等优点。     

高精度温度控制系统的设计及应用研究

为了获得连续可调谐高频微波信号,首先设计了一种基于单片机控制的高精度热电制冷器(TEC)温度控制系统,该控制系统的控制芯片采用MSP430F149单片机,通过温度传感器TMP112进行温度信息的采集,驱动电路产生的PWM波信号驱动TEC芯片进行温度的控制,稳态误差约为0.060C。其次,利用该温度控制器控制光纤的温度,通过调节TEC温度控制器的温度,获得了10.872-10.905GHz的高频微波信号,信号频移大小和温度的斜率为1.1MHz/0C,如果增加控制系统的温度调谐范围可以获得更宽调谐范围的微波信号。     

用于气体浓度检测的VCSELs温度控制电路设计

在利用可调谐半导体激光器吸收光谱（TDLAS）技术对气体浓度进行检测时,检测系统对激光器的温度稳定性要求较高。提出了一种基于max1978的VCSEL激光器自动温度控制（ATC）方案,建立了热电制冷器（TEC）的数学模型,对TEC的热惯性进行了测试,以热惯性测试结果为基础对比例积分微分控制（PID）电路参数进行了整定,设计出了具有较高控制性能的温度控制电路。电路采用闭环负反馈自动控制方案,采用PID电路产生控制信号,驱动TEC,实现了对VCSEL激光器工作温度的有效控制。实验测试结果表明,电路的温度控制精度达到+0.03℃,较好地实现了激光器工作温度稳定性的控制。     

基于ADF4110的频率发射系统

结合美国ADI公司推出低功耗宽带集成锁相环芯片ADF4110的性能特点以及锁相环频率合成器的原理,给出了用ADF4110锁相环芯片设计频率自动跟踪系统的硬件电路,并给出了频域和时域的测试结果,表明电路可以进行精确实时功率控制和本振频率控制,可以满足不同频点发射机的要求。     

基于高精度TEC温度控制器的可调光子微波信号产生的研究

为了获得高频可调谐光子微波信号源,设计了一种基于单片机的高精度TEC温度控制器,其控制芯片采用新华龙C8051F023单片机,通过数字温度传感器TMP112采集温度信息,由控制电路产生的脉宽调制(PWM)波驱动TEC芯片;同时设计了结构简单的单频布里渊激光器,利用TEC温度控制器控制布里渊激光器的增益介质,通过调节TEC的温度以及入射信号的波长,获得了10.837~11.076GHz的可调谐微波信号,且产生的微波信号可以进一步的展宽调谐范围。     

Junction temperature management of IGBT module in power electronic converters

IGBT power module is the key component of the power electronic converter, but it has the lowest reliability. The junction temperature is the crucial factor which affects power module’s reliability. To some extent, the power handling capability of the converter depends on the thermal stress of the power module. Thermal management is an effective method to improve the reliability of power device, as well as enhance the power capability. For this purpose, this paper introduces the reliability design to the power converter’s traditional compensation controller design for the first time. A new concept of generalized dual-loop controller, which includes temperature control loop and electric power control loop, is proposed. The reliability and stability of the system are both considered, with the help of the hybrid controller, the power converter can operate steadily with higher reliability. The novelty of this paper is to improve the thermal control method of carrier frequency adjustment through experimental implementation during the full life cycle of the converter. The target is to control the temperature variation to be almost a constant value as well as extend the lifetime of the converter. IR sensor is used to measure the chip temperature of the unpackaged IGBT module. The temperature variation and the average temperature are all considered in thermal management, from the reliability improvement point of view. At last, the idea is digital implemented based on a varying load of power inverter system with real-time measurement of the chip’s surface temperature.     

LTC1923在DWDM激光器温控电路中的应用

对Linear公司最新推出的高效热电制冷器（TEC）控制芯片LTC1923做了介绍，该芯片采用固定频率，电压模式进行温度控制，主控制回路采用比较放大和PWM控制，并为激光器提供了保护功能。还介绍了应用该芯片设计的DWDM激光器温度控制电路，给出了实测数据和波形。     

Dynamically inserting, operating, and eliminating thermal sensors of FPGA-based systems

In this paper, a new thermal monitoring strategy suitable for field programmable logic array (FPGA)-based systems is developed. The main idea is that a fully digital temperature transducer can be dynamically inserted, operated, and eliminated from the circuit under test using run-time reconfiguration. A ring-oscillator together with its auxiliary blocks (basically counting and control stages) is first placed in the design. After the actual temperature of the die is captured, the value is read back via the FPGA configuration port. Then, the sensor is eliminated from the chip in order to release programmable resources and avoid self-heating. All the hardware of the sensor is written in Java, using the JBits API provided by the chip manufacturer. The main advantage of the technique is that the sensor is completely stand-alone, no I/O pads are required, and no permanent use of any FPGA element is done. Additionally, the sensor is small enough to arrange an array of them along the chip. Thus, FPGAs became a new tool for researchers interested in the thermal aspects of integrated circuits.     

Inductor-less, capacitor-less state-variable electrothermal filters

Electrothermal circuits (ETC) exploit interactions between thermal and electronic properties of devices in an integrated circuit to perform useful electronic functions. An ETC integrator is described which can be used as a building block for state-variable filters. Circuits are given which perform the coefficient-setting function for such filters. Measured data are given for low-pass, high-pass, bandpass, and notch state-variable ETC filters; these filters use only transistors and resistors. For the chip size used, the maximum frequency of the filters is of the order of 200 Hz; an order of magnitude increase is possible with reduced chip size. Methods are described for making filter performance independent of ambient temperature.     

Fast-response silicon flow sensor with an on-chip fluid temperature sensing element

A new silicon flow sensor with a robust thermal isolation structure has been developed. The thermal isolation structure is mainly made of a 20-µm-thick oxidized porous silicon membrane. This thermal isolation structure makes it possible for the sensor to have a fast-response characteristic and an on-chip fluid temperature sensing element design. The sensor can be used in liquid flow as well as gas flow. Its operation is based on heat transfer from the heated sensor to a moving fluid. It has two platinum thin-film resistors, a heating element, and a fluid temperature sensing element on the chip. The sensing element is thermally isolated from the heating element. The external circuit of the sensor maintains a constant temperature difference between the heating element and the fluid. The sensor chip characteristics were evaluated theoretically by heat transfer analysis during the chip design. Measurements were made for oil flow velocity of 0-30 cm/s and air flow velocity of 0-14 m/s. Response time was below 100 ms, and a compensated output for fluid temperature change was obtained.