自适应开启时间的Buck型DC-DC控制器设计实现

设计了一种基于自适应开启时间(adaptive on-time, AOT)控制的Buck型DC-DC控制器电路,利用输入电压前馈和输出电压反馈技术来获得开启时间,并提出了一种充电电流补偿和充电时间超前电路,校正了开启时间的线性度.AOT控制保证了转换器在无需内部振荡器的条件下,工作于固定频率脉冲宽度调制模式,并改善了输出电压的纹波特性.AOT控制使系统在负载阶跃时能够连续开启最小关断时间的开关周期或连续关断,从而快速调节电感电流,极大地提高了系统的瞬态响应速度.自动跳跃式脉冲频率调制模式,有效地改善了轻负载下的转换效率.芯片采用UMC 0.6μm BCD工艺投片验证,并出了详细的测试结果.     

自适应开启时间的电流模Buck控制器

设计了一种基于自适应开启时间（Adaptive On-Time, AOT）控制的电流模buck型DC-DC控制器电路,利用输入电压前馈和输出电压反馈技术来获得开启时间,并提出了一种采样保持和充电时间超前电路实现了开启时间的自适应控制。电流模AOT控制不仅获得了优异的瞬态响应速度,而且克服了电压模开启时间控制的环路稳定性对输出电压纹波的依赖。电流模AOT控制无固定频率峰值电流控制中的亚谐波振荡问题,不需要斜坡补偿。自动跳跃式（Auto-Skip）脉冲频率调制（Pulse Frequency Modulation, PFM）模式有效地改善了轻负载下的转换效率。芯片采用UMC 0.6-μm BCD工艺投片验证,文章最后给出了详细的测试结果。     

自适应开启时间Buck变换器定时器电路设计

设计了一种用于自适应开启时间(adaptive on-time,AOT)Buck型DC-DC变换器的定时器电路,采用了输入电压前馈补偿和输出反馈技术,使开关频率不随输入、输出电压变化,实现了固定频率的伪脉冲宽度调制。基于0.18μm BCD工艺进行电路设计,并使用Hspice仿真验证。仿真结果表明当输入电压从5~18 V,相同输出电压下开关频率变化不超过10 k Hz,不同的输出电压下系统开关频率变化不超过20 k Hz。同时,由于定时器中采用输入电压前馈技术,提高了输入线性瞬态响应速度。     

一种采用SCOVP技术的高频率稳定度Buck变换器

提出了一种采用单周期输出电压预测(SCOVP)技术的自适应导通时间(AOT)控制Buck变换器。该变换器可以在输入输出电压及负载变化时实现频率恒定,并可设置外部电阻使Buck变换器准确工作在高开关频率下。首先分析了传统AOT控制Buck变换器的开关频率产生漂移的原因,并提出了一种采用SCOVP技术的单脉冲计时器(OST)电路。其次通过单周期占空比预测输出电压信息,并根据预测的输出电压和负载电流补偿T_ON时间,实现了Buck的频率稳定。该变换器采用0.18μm BCD工艺进行电路设计。仿真结果表明,在2 MHz开关频率下,负载电流从1 A到5 A变化时,Buck变换器的最大频率变化Δf_SW仅13 kHz,负载平均频率变化Δf_SW/ΔILoad为3.24 kHz/A。同时,变换器频率设置准确度从88%提升到99.35%。     

一种峰值电流模式下的轻载高效Buck转换器设计

提出了一种峰值电流模PWM下的轻载高效Buck DC-DC控制方案,该方案采用了峰值电流开关和采样保持电路,实现宽负载范围内很高的转换效率.其中峰值电流开关用以检测负载电流大小,作为轻载或者重载模式的判定;采样保持电路会在轻载模式下工作,通过控制误差信号的变化量来循环开启或者关闭转换器,完成对转换器的开关频率调制.采用0.5μm BCD工艺,仿真结果显示在输入电压12V,输出电压3.3V下,最高有96%的转换效率,而在10mA负载下依然能保持80.3%的转换效率.     

基于DC-DC转换器的锯齿波振荡器的设计

基于升降压一体直流一直流流转换器系统,针对传统的三角波产生时的放电时间作了特殊处理,控制了波形每个周期开启时间点的选择,从而达到统一放电时间点的目的.设计了一种输出频率稳定,调频范围宽,且满足同步整流要求的锯齿波振荡器电路.达到了应用于同步整流直流一直流电路脉冲宽度调制的要求.基于华润上华500纳秒CMOS工艺,通过Cadence Spectre仿真,结果显示,振荡器输出频率稳定,且对温度和电源电压不敏感.完全满足升降压一体直流一直流转换器系统要求.     

一种PFM控制模式高效反激转换器的设计

设计了一种不连续导通模式(DCM)下高效反激式转换器的控制方案。该方案通过电压检测(VS)端电感检测功率MOS管的导通状态,通过控制电路对VS信号进行采样和保持,采样值输入至降频电路产生降频电流,降低振荡器的工作频率,从而减少功率MOS管的开关损耗,提高转换器的工作效率。在不同的输出负载下,VS的采样值产生不同大小的降频电流不同程度降低振荡器的工作频率,实现对系统的脉冲频率调制和脉冲宽度调制的结合控制。本电路采用0.5μm BiCMOS工艺,利用Hspice和Cadence软件对设计的电路进行仿真。仿真结果表明,转换器的效率高达86%,在0.1 A轻载情况下效率也达到了72.1%,较高的工作效率满足设计要求。     

一种新颖的开关电源调制模式

为了解决开关电源PWM模式在轻载时的效率低下和PFM模式输出噪声频带比较宽,滤波难度大的问题,提出了一种新颖的开关电源调制模式-跳周期调制(SCM)结合可变极限电流比较器双环控制模式.提出SCM的控制机理和理论模式,SCM模式的效率比常规的PWM高,且基本上与负载无关;通过可变极限电流比较器对负载进行监测形成双环路控制模式,提高了电源的响应度,降低了开关电源的电磁干扰和输出纹波电压.分析了其效率和负载的关系,并与PWM、PFM调制模式进行了比较,得出SCM结合可变极限电流比较器双环控制模式是一种在不同负载下均有很高效率的调制模式,特别适用于在满载下工作时间相对不长的中小功率电源系统.     

基于自适应频率DPWM的数字控制Buck变换器

为了用于固定频率电压模PWM控制,提出了一种基于自适应频率DPWM的数字控制Buck变换器。在负载阶跃响应时,DPID的输出值发生改变,以调制PWM信号的占空比;DPWM频率根据输出误差值而变化,提高了PWM信号的调制强度。通过小数分频和检测ADC输出,实现了DPWM频率的变化。采用分段调节的方式,有效改善了电路的瞬态响应。该Buck变换器基于0.18 μm CMOS工艺设计。仿真结果表明,当负载电流在10~20 A范围变化时,过冲电压降低了5 mV,恢复时间缩短了10.5 μs,下冲电压降低了8 mV,恢复时间缩短了9.6 μs。     

CMOS开关电源中的节能控制器的设计与实现

传统节能控制器调控CMOS开关电源中,通过脉冲频率调制的方法实现开关电源负载情况进行控制,但是该方法无法解决负载电流的大规模波动问题,抗噪性能较低,节能控制效果较差。因此,设计并实现一种基于脉冲宽度调制的低功耗CMOS式开关电源节能控制器,该控制器融合脉冲宽度调制(PWM)和脉冲跨周期调制(PSM)进行负载控制。若反馈电压取值范围波动不大,则采用脉冲宽度调制,运行时钟下降沿并关停峰值电流,输出控制波形;若波动较大,则采用脉冲跨周期调制,避免控制波形的输出,使得功率开关管处于关断状态,降低功率开关管的损耗。实验结果表明,设计的节能控制器控制CMOS开关电源具有较好的输入电压调整率和负载调整率,最高转换效率可达98%,节能控制效果较好。     

A current-mode buck DC-DC controller with adaptive on-time control

A current-mode buck DC-DC controller based on adaptive on-time (AOT) control is presented. The on-time is obtained by the techniques of input feedforward and output feedback, and the adaptive control is achieved by a sample-hold and time-ahead circuit. The AOT current-mode control scheme not only obtains excellent transient response speed, but also achieves the independence of loop stability on output capacitor ESR. In addition, the AOT current-mode control does not have subharmonic oscillation phenomenon seen in fixed frequency peak current-mode control, so there is no need of the slope compensation circuit. The auto-skip pulse frequency modulation (PFM) mode improves the conversion efficiency of light load effectively. The controller has been fabricated with UMC 0.6-μm BCD process successfully and the detailed experimental results are shown.     

Adaptive current-threshold detector for an adaptive on-time Buck converter at light load

The adaptive on-time control technique has been tremendously utilized in DC–DC converters for its fast transient response, easier design and high efficiency at light load. In some applications the output voltage ripple of DC–DC converters has to be maintained within an acceptable level to achieve superior performance, which depends largely on the load current for adaptive on-time buck converters when operating in discontinuous conduction mode. This paper proposes an adaptive current-threshold detection method for reducing the output voltage ripple. An actual detector circuit is presented to implement the method. This circuit monitors the relationship between the peak inductor current and the load current at light load. Then it outputs a logic signal which controls the turn-on time of the main power MOSFET and hence the peak inductor current. Therefore, the magnitude of the output voltage ripple is controlled. The current-threshold detection method has been verified in an adaptive on-time buck converter by simulation and experimental results. The proposed method can also be used in other constant on-time converters.     

Multi-energy harvesting SIMO converter with energy prediction and adaptive output priority

A single-inductor-multi-output boost converter is presented to boost the low voltage generated by the photovoltaic and thermoelectric generator for the body sensor nodes. A modified single charging single discharging control combined constant on-time control and adaptive output priority is proposed to achieve a good transient response. The adaptive output priority is determined by a hungry algorithm, which just senses the output voltages of the presented converter. Furthermore, an exponentially weighted moving average algorithm is introduced to choose the solar, thermal or stored energy as the supply source. Moreover, the presented converter is self-powered by its own output after starting-up. Finally, the presented converter is designed and verified in the CSMC CMOS 0.18µm 1P6M process.     

AOT控制的降压型转换器的稳定性分析

为了保证自适应导通时间控制的降压型转换器能在输入电压全范围内正常工作,通过理论分析和时域推导,研究了输出电容的ESR对系统稳定性的影响。结果表明,只有ESR足够大,才能保证其电压变化率大于输出电容电压变化率,从而保证系统的稳定。此外,建立了ESR的最小临界值与输入电压之间的数学模型,并揭示了二者存在反比例关系。不同ESR条件下的输入电压扰动时域仿真结果说明了ESR对系统稳定的重要性。通过比较理论数学模型的拟合曲线与实际仿真结果,验证了理论分析和数学模型的正确性。     

A buck converter with adaptive on-time PFM control and adjustable output voltage

This letter proposes a new adaptive on-time pulse-frequency modulation (PFM) circuit that operates at a wide range of supply voltage levels and that can generate various output voltage levels compared to conventional circuits. The circuit’s peak inductor current is well-controlled; the magnitude of the output ripple voltage is constant, even when the supply and output voltage levels are significantly different. Since the ripple voltage is a noise component, constant ripple voltage is important for predictable noise of a power management system.     

A Direct PWM Technique for a Single-Phase Full-Bridge Inverter Through Controlled Capacitor Charging

The controlled-capacitor-charging (CCC) technique is utilized in this paper to synthesize a sinusoidal voltage at the output from the unregulated dc at the input. The method is based on the controlled charging/discharging of a capacitor to realize the desired voltage waveform. A capacitor that is connected across the load is charged/discharged through an inductor by applying high-frequency pulses. The applied pulses could be of either positive or negative polarity, depending on the error signal in the controller. The controller senses the output voltage and current and operates to maintain zero-current switching at every turn-on while keeping the output voltage close to the reference waveform by a tracking-control algorithm, enforcing limits in maximum switching frequency and voltage ripples. This paper presents a direct method of implementing the pulsewidth modulation for the single-phase full-bridge inverter, using the CCC technique. A simple procedure to design such an inverter is also discussed. The proposed controller is simulated in a personal computer simulation program with integrated circuit emphasis. Supporting results from an experimental prototype confirm the usefulness of the proposed controller. The inverter may be used in uninterruptible power supply and many other applications.      

带MPPT控制的光伏充电控制器的设计

本文设计了一种具有MPPT控制的光伏发电充电控制器。该控制器通过检测蓄电池充电电压、充电电流的大小,智能选择充电器的工作状态,并在光照强度不足时自动切换到光伏发电最大功率点跟踪控制MPPT状态,采用扰动控制策略使光伏电池有最大的功率输出,使控制器有较好的充电效率。实验结果较好地说明所设计控制器的有效性。     

Ultra Fast Fixed-Frequency Hysteretic Buck Converter With Maximum Charging Current Control and Adaptive Delay Compensation for DVS Applications

An integrated DC-DC hysteretic buck converter with ultrafast adaptive output transient response for reference tracking is presented. To achieve the fastest up-tracking speed, the maximum charging current control is introduced to charge up the output voltage with the maximum designed current. For down-tracking, the output is discharged by the load only to save energy. Although the converter works with hysteretic voltage mode control, an adaptive delay compensation scheme is employed to keep the switching frequency constant at 850 kHz to within plusmn2.5% across the whole operation range. The integrated buck converter was fabricated using a 0.35 mum CMOS process. With an input voltage of 3 V, the output voltage can be regulated between 0.5 and 2.5 V. With a load resistor of 10 Omega, the up-tracking speed of the maximum reference step (0.5 to 2.5 V) is 12.5 mus/V. All design features are verified by extensive measurements.     

Modeling and Control of PV Charger System With SEPIC Converter

The photovoltaic (PV) stand-alone system requires a battery charger for energy storage. This paper presents the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC). The designed SEPIC employs the peak-current-mode control with the current command generated from the input PV voltage regulating loop, where the voltage command is determined by both the PV module maximum power point tracking (MPPT) control loop and the battery charging loop. The control objective is to balance the power flow from the PV module to the battery and the load such that the PV power is utilized effectively and the battery is charged with three charging stages. This paper gives a detailed modeling of the SEPIC with the PV module input and peak-current-mode control first. Accordingly, the PV voltage controller, as well as the adaptive MPPT controller, is designed. An 80-W prototype system is built. The effectiveness of the proposed methods is proved with some simulation and experimental results.     

H/sup /spl infin// repetitive control of DC-AC converters in microgrids

This paper proposes a voltage controller design method for DC-AC converters supplying power to a microgrid, which is also connected to the power grid. This converter is meant to operate in conjunction with a small power generating unit. The design of the output voltage controller is based on H/sup /spl infin// and repetitive control techniques. This leads to a very low harmonic distortion of the output voltage, even in the presence of nonlinear loads and/or grid distortions. The output voltage controller contains an infinite-dimensional internal model, which enables it to reject all periodic disturbances which have the same period as the grid voltage, and whose highest frequency components are up to approximately 1.5 kHz.