Applications of magnetic amplifiers to high-frequency DC-to-DCconverters

Control characteristics and power losses of magnetic amplifier used as a pulse-width modulator are discussed for a typical forward converter driven high-frequency switching. The control region of the magnetic amplifier is analyzed by modeling the DC magnetizing characteristics of the core and the reverse recovery of the diode in the converter circuit, and the dynamic characteristics of the regulated converter are examined analytically. The iron loss and switching loss of the magnetic amplifier are derived as functions of the switching frequency and the load current, with five states of the magnetic amplifier taken into consideration     

一种提高DC-DC瞬态响应的误差放大器设计

设计了一种可提高DC-DC瞬态响应的误差放大器,其输出阻抗和补偿电阻随着负载电流的变化动态调整,使系统在不同的负载条件下能够获取足够的相位裕度。同时,设计了采样电路和逻辑选择电路,分别用于检测负载电流变化和选择开关导通。结果显示,采用文中所提出结构,DC-DC的过冲比原来减小了50%。     

双补偿结构I-V 转换电路在红外接收芯片中的应用

设计了一款用于红外通信中的I-V 转换电路,该电路包含了一个跨阻放大器和两个补偿结构。直流补偿电路用来补偿由环境光产生的直流光电流,避免后级电路出现饱和;交流补偿电路用来提高输入交流阻抗,从而保持电路对输入信号的灵敏度。研究表明,通过对I-V 转换电路实现双补偿,整体电路的增益控制及灵敏度均有显著提高。该电路采用VIS 0.6 m BiCMOS 工艺进行设计与流片,在3 V 工作电压下,对10 nA 到300 A 的直流光电流具有良好的抑制能力,使电路的增益恒定在 110 dB,具有良好的稳定性。     

一种DC/DC斜坡补偿电路的设计

本文提出了一种峰值电流模式控制的DC/DC转换器中斜率补偿电路.电路采用上斜坡补偿（补偿信号与采样信号叠加）方式.电路由采样电路、斜坡信号产生电路、叠加电路共同组成.采样电路采样电感电流信号,并生成一个带有采样信号信息的电流信号,输入到叠加电路,与斜坡信号产生电路生成的一个斜坡电流信号进行叠加,然后共同作于一个电阻之上,输出一个带有采样信号信息与斜坡补偿信息的电压信号,实现斜坡补偿.该信号与误差放大器的输出信号共同输入到PWM（脉冲宽度调制）比较器,两信号经比较后输出驱动信号,控制功率管的关断.     

电流型运算放大器在应用电路中的特性研究

文中简要介绍了电流型运放的特性,着重对电流型运放的应用电路进行测试,研究电流型运放的应用特性。实验中,选择典型电流型运放及电压型运放构建负阻变换器、电压跟随器和同相比例放大器,通过对此3类应用电路的测试,分析、总结运放参数对特殊应用电路的影响,为电路设计者在具体电路的设计中恰当选择适合的放大器提供参考。     

InGaP/GaAs HBT射频功率放大器在片温度补偿电路研究

本文针对无线通信应用的InGaP/GaAs HBT射频功率放大器,提出一种新型的在片温度补偿电路。该温度补偿电路由一个GaAs HBT和五个阻值大小不同的电阻组成,结构简单,可实现性强。通过调整偏置电路中参考电压的方法调节功率放大器静态偏置电流,有效地实现补偿功率放大器功率增益和输出功率随温度变化的特性,优化了射频功率放大器的热特性,性能随温度只有略微的退化。将该温度补偿电路置入一个无线通信应用的三级单片集成功率放大器,温度在-20℃到＋80℃范围内变化时,增益随温度变化的变化量从4.3dB提高到只有1.1dB。     

An on-chip temperature compensation circuit for an InGaP/GaAs HBT RF power amplifier

A new on-chip temperature compensation circuit for a GaAs-based HBT RF amplifier applied to wireless communication is presented.The simple compensation circuit is composed of one GaAs HBT and five resistors with various values,which allow the power amplifier to achieve better thermal characteristics with a little degradation in performance.It effectively compensates for the temperature variation of the gain and the output power of the power amplifier by regulating the base quiescent bias current.The temperature compensation circuit is applied to a 3-stage integrated power amplifier for wireless communication applications,which results in an improvement in the gain variation from 4.0 to 1.1 dB in the temperature range between -20 and +80℃.     

一种应用于DC/DC转换器的高效PWM控制电路的设计

本文提出一种用于DC/DC转换器的高效PWM控制电路。该控制电路采用电流控制模式,在宽范围内有着良好的瞬态响应。斜坡补偿信号与误差放大器的输出信号进行叠加,叠加后的信号与电流采样信号进行比较,产生一个占空比信号控制功率管的通断。并且本PWM控制电路中的误差放大器与软启动结合在一起,实现输出电压平滑稳定上升,有效减少了输入电流和输出电压过冲现象,保护了系统安全。     

一种应用于InGaP/GaAs HBT射频功率放大器的在片温度补偿电路

A new on-chip temperature compensation circuit for a GaAs-based HBT RF amplifier applied to wireless communication is presented.The simple compensation circuit is composed of one GaAs HBT and five resistors with various values,which allow the power amplifier to achieve better thermal characteristics with a little degradation in performance.It effectively compensates for the temperature variation of the gain and the output power of the power amplifier by regulating the base quiescent bias current.The temp...     

一种带自适应斜坡补偿的PCM控制Boost变换器

设计了一种带自适应斜坡补偿的峰值电流模式(PCM)控制Boost变换器。采用一种低功耗自适应斜坡补偿电路,使得升压(Boost)变换器能够实现宽输出范围和高带载能力。在此基础上,提出了一种应用于Boost变换器的电感电流采样电路,该电路实现了高采样速度和高采样精度,且具备全周期的电感电流采样特点。变换器基于SMIC 180 nm BCD CMOS工艺设计。仿真结果表明,该带自适应斜坡补偿的PCM控制Boost变换器输入电压转换范围为2.8 V～5.5 V,输出电压转换范围为4.96 V～36.1 V,最大输出负载电流高达5 A。     

基于LTIViewer的放大器频率补偿分析

频率补偿可以改善负反馈放大电路的稳定性,常用的有滞后补偿、超前补偿及超前滞后补偿三种方法。由于负反馈放大电路的补偿分析与计算较为复杂,且很不直观,文中提出使用Matlab中的LTIViewer工具进行负反馈放大电路频率补偿的分析和计算,并对三种典型的频率补偿电路进行了仿真分析。文中系统给出了补偿电路参数的确定方法,分析了三种补偿电路的特点及适用范围。     

一种基于DC/DC变换器的LED驱动电路的设计

提出一种基于电流模式DC/DC变换器的驱动控制电路。该电路可以与恒流电路结合在一起,用作LED驱动。电路由误差放大器、斜坡信号产生电路、电流采样与叠加电路以及PWM比较器四部分构成。采用华虹BCD350工艺进行仿真验证,结果显示,电路成功实现了电流采样信号与斜坡补偿信号的叠加,在Vea信号的控制下,输出了控制功率管关断的PWM脉冲信号。     

A 70-MS/s 110-mW 8-b CMOS folding and interpolating A/D converter

A CMOS analog to digital converter based on the folding and interpolating technique is presented. This technique is successfully applied in bipolar A/D converters and now also becomes available in CMOS technology. The analog bandwidth of the A/D converter is increased by using a transresistance amplifier at the outputs of the folding amplifiers and, due to careful circuit design, the comparators need no offset compensation. The result is a small area (0.7 mm² in 0.8 μm CMOS), high speed (70 MS/s), and low-power (110 mW at 5 V supply, including reference ladder) A/D converter. A 3.3 V supply version of the circuit runs at 45 MS/s and dissipates 45 mW     

增强升压型DC-DC瞬态响应的电路设计

设计了一种增强升压型DC-DC转换器瞬态响应电路,该电路通过检测负载跳变条件下输出电压的变化,调节误差放大器的跨导和补偿电阻,提高升压DC-DC转换器环路带宽,加快系统的瞬态响应。同时将该电路应用于一款输入电压＜至1.4 V,输出电压2.5～6.5 V的同步升压型DC-DC转换器中,其在0.25 μm CMOS 工艺条件下,芯片仿真结果表明,在500 mA~2 A的负载跳变条件下,与传统同步升压DC-DC转换器相比,芯片的响应恢复时间减小了45%,输出电压的下降和过冲值减少了35%。     

一种性能优异的毫米波温度补偿电路设计

采用温度传感器电压控制毫米波电调二极管,设计了一种新的毫米波温度补偿电路,与放大器增益链路的常用几种温度补偿电路相比较,其具有电路形式简单、温度补偿精确等显著特点.测试结果表明在-40℃~+70℃温度范围内毫米波增益波动1 dB,该电路对温度补偿电路的工程化使用具有重要意义.     

推挽DC-DC变换器建模与控制设计

运用状态空间平均法,推导出连续导电模式下非理想电压型推挽DC-DC变换器功率级电路的低频小信号传递函数,仿真出变换器功率级电路的幅频和相频曲线（Bode图）,通过优化设计反馈补偿电路,可以提高电压型推挽DC-DC变换器系统的稳定性和动态特性。对一台电压型推挽DC-DC变换器样机进行仿真和控制设计,应用网络分析仪Agilent4395A分别测试功率级电路和变换器系统的Bode图,并应用示波器测试变换器系统的负载动态响应,验证了建模和控制设计的正确性。     

低压CMOS带隙电压基准源设计

在对传统典型CMOS带隙电压基准源电路分析和总结的基础上,综合一级温度补偿、电流反馈技术,提出了一种1-ppm/°C低压CMOS带隙电压基准源。采用差分放大器作为基准源的负反馈运放,简化了电路设计。放大器输出用作电路中PMOS电流源偏置,提高了电源抑制比(PSRR)。整个电路采用TSMC0.35μmCMOS工艺实现,采用HSPICE进行仿真,仿真结果证明了基准源具有低温度系数和高电源抑制比。     

Modeling of control loop behavior of magamp post regulators

Small signal-control models are presented for a magnetic amplifier switching-mode post regulator for SMPS applications. Two commonly used current reset schemes are considered; an external reset scheme and a self-reset scheme. It is mathematically shown that the open-loop gain is a two-pole, single-zero transfer function for continuous-mode operation and is a single pole transfer function for discontinuous mode operation. The equations for predicting the open-loop gains for both types of reset circuits are derived and verified experimentally. It is shown that the open-loop gain characteristics of a magnetic-amplifier regulator depends on power circuit parameters, the reset-circuit parameters, and the saturable reactor parameters. Models for both continuous mode and discontinuous modes of operation that provide designers with useful tools for designing a compensation network for the feedback error amplifier are presented     

一种新型高精度斜坡补偿电路

针对采用高端功率MOSFET的导通电阻作电流取样电阻的同步整流电流模式降压DC-DC变换器,设计了一种新型高精度斜坡补偿电路.该电路采用有一定死区时间的同步整流,防止主功率管和续流管同时导通.死区过后,主功率管给电感充电,此时,续流管漏极寄生电容还在放电,造成电流采样误差.针对该问题,提出一种斜坡补偿电路,进行误差消除...     

Robust feedforward compensation scheme with AC booster for high frequency low voltage buck DC–DC converters

Today and in the future, high frequency low voltage DC–DC converters are an effective power-management solution for fast transient response and small profile in portable electronic systems. This paper presents a robust feedforward compensation scheme with AC booster. An ac amplifier is added in parallel with the main path to compensate the high-frequency gain reduction, which improves gain-bandwidth (GBW) product and slew rate significantly. This approach takes the multistage error amplifier (EA) as an element in the compensation circuit instead of using passive elements used in traditional proportional-plus-integral-and-derivative (PID) compensation circuits. The positive phase shift of left-half-phase (LHP) zeros caused by the feedforward path and ac boosting path in the multistage EA is used to cancel the negative phase shift by the resonant poles of the power stage of buck DC–DC converter in order to compensate the DC–DC converters. A graphical loop-gain method is used to design the feedback compensation and analyze the closed-loop performances of the converter for the complexion arising from the presence of multiple poles of EA before crossover frequency in high frequency converters. The high gain, wide bandwidth, and high slew rate are achieved by the absence of traditional pole-splitting effect and the added ac booster. In addition, the design guidelines for this feedback compensation network realized by robust feedforward with AC booster compensation (RFACBC) scheme and multistage EA are established. When the proposed compensation networks were employed in 100 MHz buck DC–DC converter implemented in SMIC 0.18 μm CMOS process, the simulation results validate the feasibility and functionality of the RFACBC scheme and design guidelines. The closed-loop dc gain achieves over 60 dB with over 20 MHz GBW and 61° phase margin under wide range loads. Furthermore, the settling time is improved due to the advanced frequency compensation.