高速负载响应DC-DC开关电源IC设计
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摘要
近年来,电池供电便携式设备(如PDA、手机、MP3播放器等)的需求越来越大,对DC-DC开关电源IC的需求也日益增大,同时对其性能要求也越来越高。要求DC-DC转换器具有高转换效率,以延长电池供电时间;并具有良好的瞬态响应特性,以满足CPU、DSP和闪存等模块的要求。
根据电池供电便携式设备的要求,本论文设计了一款高速负载响应DC-DC开关电源IC芯片。该芯片采用0.6μm CMOS工艺实现,集成有高精度基准电压源,振荡器,斜坡补偿功能电路,电流限制,电流采样电路,求和比较器,负载调整积分等电路模块。该芯片的输入电压范围为2.7V-5.5V,输出电压范围从输入到13V连续可调,工作频率为250KHZ,同时具有输出电压纹波小,转换效率高,负载调整能力强等特点。
本文设计的开关电源芯片采用电流控制PWM调制方式,运用一种新颖的求和比较器电路来代替传统开关电源中误差放大器和PWM比较器的级联结构,减少了传统开关电源中误差放大器带来的误差和延时,加强了PWM调制的精度和速度,提高了系统的负载响应速度。根据系统需要,本文还利用了负载调整积分器来消除系统稳态误差,增强系统的负载调整能力。同时,本文还对系统的稳定性和芯片的效率进行了详细的分析。
最后,本文利用仿真软件Hspice对整体电路进行了仿真验证。仿真结果表明,本文设计的DC-DC变换器在典型应用条件下,其输出电压纹波小于1%,最高转换效率超过85%,当负载电流从10mA跃变到100mA,其动态跌落量小于1%,恢复时间最快达25μs,利用负载调整积分器可以显著增强系统的负载调整能力,消除系统因负载调整引起的稳态误差。
In recently year,there is a rapid increasing market demanding for battery-powered portable equipments(such as PDAs,Mobiles,etc),which requires the DC-DC converter with high efficiency to boost the battery supply capability and good large signal property to satisfy the special demand of the CPU,DSP and flash memory.
We build a high speed load response DC-DC SMPS(Switch Mode Power Supply) IC which is fabricated with 0.6μm CMOS process and integrated with high precision voltage reference,OSC,Slope-compensation function circuit,current limit circuit, current sample circuit,sum-comparator,load regulation integrator and so on.The allowable input voltage ranges from 2.7V to 5.5V and its output voltage can be programmed between 2.7V and 13V,and its operation frequency is 250 kHz.It also has some excellent characteristics,such as lower output ripple,high convert efficiency,and strong ability of load regulation.
The SMPS presented by this thesis is based on current control PWM modulation. We use a novel circuit structure in this thesis,which is used to predigest the cascade of error amplifier and PWM comparator used in traditional SMPS:sum-comparator.The sum-comparator can reduce the error and delay caused by the error amplifier in the traditional SMPS.For this,it could improve the speed and precision of PWM modulation and enhance the load response performance.The load regulation integrator is given to eliminate the steady state error in system and enhance the ability of load regulation according to the system demand.In addition,we analyze the stability of the system and the efficiency of the IC carefully.
At the end of the thesis,we simulate the whole circuit by Hspice.Through the simulation result,under a typical application,the DC-DC conveter' features show as follows:output voltage ripple is less than 1%,the highest convert efficiency is up to 85%.When the load current step from 10mA to 100mA,the dynamic sag is less than 1%and the fastest restore time is 25μs.In addition,load regulation integrator can enhance the load regulation ability of the system effectively and eliminates the steady state error caused by load regulation.
根据电池供电便携式设备的要求,本论文设计了一款高速负载响应DC-DC开关电源IC芯片。该芯片采用0.6μm CMOS工艺实现,集成有高精度基准电压源,振荡器,斜坡补偿功能电路,电流限制,电流采样电路,求和比较器,负载调整积分等电路模块。该芯片的输入电压范围为2.7V-5.5V,输出电压范围从输入到13V连续可调,工作频率为250KHZ,同时具有输出电压纹波小,转换效率高,负载调整能力强等特点。
本文设计的开关电源芯片采用电流控制PWM调制方式,运用一种新颖的求和比较器电路来代替传统开关电源中误差放大器和PWM比较器的级联结构,减少了传统开关电源中误差放大器带来的误差和延时,加强了PWM调制的精度和速度,提高了系统的负载响应速度。根据系统需要,本文还利用了负载调整积分器来消除系统稳态误差,增强系统的负载调整能力。同时,本文还对系统的稳定性和芯片的效率进行了详细的分析。
最后,本文利用仿真软件Hspice对整体电路进行了仿真验证。仿真结果表明,本文设计的DC-DC变换器在典型应用条件下,其输出电压纹波小于1%,最高转换效率超过85%,当负载电流从10mA跃变到100mA,其动态跌落量小于1%,恢复时间最快达25μs,利用负载调整积分器可以显著增强系统的负载调整能力,消除系统因负载调整引起的稳态误差。
In recently year,there is a rapid increasing market demanding for battery-powered portable equipments(such as PDAs,Mobiles,etc),which requires the DC-DC converter with high efficiency to boost the battery supply capability and good large signal property to satisfy the special demand of the CPU,DSP and flash memory.
We build a high speed load response DC-DC SMPS(Switch Mode Power Supply) IC which is fabricated with 0.6μm CMOS process and integrated with high precision voltage reference,OSC,Slope-compensation function circuit,current limit circuit, current sample circuit,sum-comparator,load regulation integrator and so on.The allowable input voltage ranges from 2.7V to 5.5V and its output voltage can be programmed between 2.7V and 13V,and its operation frequency is 250 kHz.It also has some excellent characteristics,such as lower output ripple,high convert efficiency,and strong ability of load regulation.
The SMPS presented by this thesis is based on current control PWM modulation. We use a novel circuit structure in this thesis,which is used to predigest the cascade of error amplifier and PWM comparator used in traditional SMPS:sum-comparator.The sum-comparator can reduce the error and delay caused by the error amplifier in the traditional SMPS.For this,it could improve the speed and precision of PWM modulation and enhance the load response performance.The load regulation integrator is given to eliminate the steady state error in system and enhance the ability of load regulation according to the system demand.In addition,we analyze the stability of the system and the efficiency of the IC carefully.
At the end of the thesis,we simulate the whole circuit by Hspice.Through the simulation result,under a typical application,the DC-DC conveter' features show as follows:output voltage ripple is less than 1%,the highest convert efficiency is up to 85%.When the load current step from 10mA to 100mA,the dynamic sag is less than 1%and the fastest restore time is 25μs.In addition,load regulation integrator can enhance the load regulation ability of the system effectively and eliminates the steady state error caused by load regulation.
引文
[1]杨旭,裴元庆,王兆安.开关电源技术.北京:机械工业出版社,2004:61-125
[2]赵军.开关电源技术的发展.船电技术,2005,5:13-16
[3]张小林,冉建桥,李贤云.我国开关电源发展的思考.微电子学,2004,34(4):402-406[2]
[4]Ognjen Djekic,Mild Brkovic.Synchronous rectifiers vs Schottky diodes in a buck topology for low voltage applications.Power Electronics Specialists Conference,1997.PESC '97 Record.28th Annual IEEE,1997,2:1374-1380
[5]G.Hua.A New Class of ZVS-PWM Converters.High Frequency Power Conversion Conference Proccedings,1991:244-251
[6]TAM,Hung Shun Vincent,Loop Gain Simulation and Measurement of PWM Switching Converters,Master Thesis of The Hong Kong University of Science and Technology November 1999
[7]郭创,张宗麟,樊蓉.常规开关电源拓扑结构及典型应用电路.电子元件与材料,2003,22(8):38-41
[8]华伟.通信开关电源的五种PWM反馈控制模式研究.通信电源技术,2001,(2):8-11
[9]Vorperian V.Simplified analysis of PWM converters using model of PWM switch-Part Ⅰ:Continuous conduction mode.IEEE Trans.Aerospace Electron.Syst,1990,vol.26:490-496
[10]Mulligan Michael D,Broach Bill Lee,Thomas H.A Constant-Frequency Method for Improving Light-Load Efficiency in Synchronous Buck Converters.IEEE Power Electronics Letters,2005,3(1):24-29
[11]王创社,乐开端.开关电源两种控制模式的分析与比较.电力电子技术,1998,Vol3:7-81
[12]曲学基,王增福.新编高频开关稳压电源.北京:电子工业出版社,2005,90-92
[13]郭家荣,孟祥瑞,周耀.DC-DC开关电源管理芯片的设计.微型计算机信息,2005,21(1):152-153
[14]Pivit E,Saxarra J.On Dual Control Pulse Width Modulated for Stable Operation of Switched Power Supplies.Wiss.Ber.AEG2Telefunken,1979,52(5):243-249
[15]郝琦玮,李树华.开关电源的原理与设计.内蒙古大学学报(自然科学版),2003, 34(4):440-444
[16]俞阿龙.电流控制P删开关电源.电声技术,2002,11:33-35
[17]毛鸿,吴兆麟.电流控制模式开关电源的分析与设计.工业仪表与自动化,1999,6:42-44
[18]Hung-Chi Lee,Kuo-Tai Chang,Ke-Homg Chen.Power saving of a dynamic width controller for a monolithic current-mode CMOS DC-DC converter.System-on-Chip for Real-Time Applications,2005.Precedings.Fifth International Workshop on 20-24 July 2005 Page(s):352-357
[19]Arbetter.B,Erickson.R,Maksimovic.D.DC-DC Converter Design for Battery-Operated Systems.Power Electroniea Specialists Conference,1995.PESC '95 Record.26th Annual IEEE Volume 1,18-22 June 1995 Page(s):103-109 vol.1
[20]Mulligan.M.D,Broach.B,Lee.T.H.A Constant-Frequency Method for Improving Light-Load Efficiency in Synchronous Buck Conw'rters.Power Electronics Letters,IEEE Volume 3,Issue 1,March 2005 Page(s):24-29
[21]长谷川彰著,何希才译.开关稳压电源的设计与应用.北京:科学出版社,2006,169-170
[22]Modeling Analysis and Compensation of the Current-mode Converter.Unitrode Application Note,U-97
[23]杨汝.峰值电流控制模式中斜坡补偿电路的设计.电力电子技术,2001,35(3):35-38
[24]高原,邱新芸,汪晋宽.峰值电流控制开关电源斜坡补偿的研究.仪器仪表学报,2003,24(4):118-120
[25]来新泉,周丽霞,陈富吉.升压型Dc-DC转换器中的动态斜坡补偿电路设计.微电子学,第35卷第4期,2005年8月
[26]R.B.Ridley.A new,continuous-time model for current-mode control,IEEE Trans.Power Elecron.Vol.6:271-280,April 1991
[27]F.Dong,Tan R.D.A unified model for current programmedconverter.IEEETrans.PowerElecron,July 1995,Vol.10,No.4:397-408
[28]Bryant.B,Kazimierczuk.M.K.Sample and hold effect in PWM DC-DC converters with peak current-mode control Circuits and Systems.2004.ISCAS '04.Proceedings of the 2004International Symposium on Volume 5,23-26 May 2004 Page(s):V-860-V-863
[29]Dixon.Closing the Feedback Loop.Unitrode Power Supply Design Seminar Manual-500:C1-1-1-31,1986
[30]Arbetter.B,Maksimovic.D.DC-DC converter with fast transient response and high efficiency for low-voltage microprocessor loads.Applied Power Electronics Conference and Exposition,1998.APEC'98.Conference Proceedings 1998,Thirteenth Annual Volume 1,15-19 Feb.1998Page(s):156-162 vol.1
[31]Rais Miftakhutdinov.Analysis and Optimization of Synchronous Buck Converter at High Slew-Rate Load Current Transients.Power Electronics Specialists Conference,2000.PESC 00.2000 IEEE 31 st Annual Volume 2,18-23 June 2000 Page(s):714-720 vol.2
[32]Lioyd H,Dixon.Current-mode control of switching power supply,www.ti.eom
[33]Redl.R,Erisman.B.P,Zansky.Z.Optimizing the load transient response of the buck converter.Applied Power Electronics Conference and Exposition,1998.APEC'98.Conference Proceedings 1998,Thirteenth Annual Volume 1,15-19 Feb.1998 Page(s):170-176 vol.1
[34]邹雪城,邵轲,郑朝霞.开关电源芯片中过温保护技术的研究与实现.微电子学与计算机,2006,23(7):193-194
[2]赵军.开关电源技术的发展.船电技术,2005,5:13-16
[3]张小林,冉建桥,李贤云.我国开关电源发展的思考.微电子学,2004,34(4):402-406[2]
[4]Ognjen Djekic,Mild Brkovic.Synchronous rectifiers vs Schottky diodes in a buck topology for low voltage applications.Power Electronics Specialists Conference,1997.PESC '97 Record.28th Annual IEEE,1997,2:1374-1380
[5]G.Hua.A New Class of ZVS-PWM Converters.High Frequency Power Conversion Conference Proccedings,1991:244-251
[6]TAM,Hung Shun Vincent,Loop Gain Simulation and Measurement of PWM Switching Converters,Master Thesis of The Hong Kong University of Science and Technology November 1999
[7]郭创,张宗麟,樊蓉.常规开关电源拓扑结构及典型应用电路.电子元件与材料,2003,22(8):38-41
[8]华伟.通信开关电源的五种PWM反馈控制模式研究.通信电源技术,2001,(2):8-11
[9]Vorperian V.Simplified analysis of PWM converters using model of PWM switch-Part Ⅰ:Continuous conduction mode.IEEE Trans.Aerospace Electron.Syst,1990,vol.26:490-496
[10]Mulligan Michael D,Broach Bill Lee,Thomas H.A Constant-Frequency Method for Improving Light-Load Efficiency in Synchronous Buck Converters.IEEE Power Electronics Letters,2005,3(1):24-29
[11]王创社,乐开端.开关电源两种控制模式的分析与比较.电力电子技术,1998,Vol3:7-81
[12]曲学基,王增福.新编高频开关稳压电源.北京:电子工业出版社,2005,90-92
[13]郭家荣,孟祥瑞,周耀.DC-DC开关电源管理芯片的设计.微型计算机信息,2005,21(1):152-153
[14]Pivit E,Saxarra J.On Dual Control Pulse Width Modulated for Stable Operation of Switched Power Supplies.Wiss.Ber.AEG2Telefunken,1979,52(5):243-249
[15]郝琦玮,李树华.开关电源的原理与设计.内蒙古大学学报(自然科学版),2003, 34(4):440-444
[16]俞阿龙.电流控制P删开关电源.电声技术,2002,11:33-35
[17]毛鸿,吴兆麟.电流控制模式开关电源的分析与设计.工业仪表与自动化,1999,6:42-44
[18]Hung-Chi Lee,Kuo-Tai Chang,Ke-Homg Chen.Power saving of a dynamic width controller for a monolithic current-mode CMOS DC-DC converter.System-on-Chip for Real-Time Applications,2005.Precedings.Fifth International Workshop on 20-24 July 2005 Page(s):352-357
[19]Arbetter.B,Erickson.R,Maksimovic.D.DC-DC Converter Design for Battery-Operated Systems.Power Electroniea Specialists Conference,1995.PESC '95 Record.26th Annual IEEE Volume 1,18-22 June 1995 Page(s):103-109 vol.1
[20]Mulligan.M.D,Broach.B,Lee.T.H.A Constant-Frequency Method for Improving Light-Load Efficiency in Synchronous Buck Conw'rters.Power Electronics Letters,IEEE Volume 3,Issue 1,March 2005 Page(s):24-29
[21]长谷川彰著,何希才译.开关稳压电源的设计与应用.北京:科学出版社,2006,169-170
[22]Modeling Analysis and Compensation of the Current-mode Converter.Unitrode Application Note,U-97
[23]杨汝.峰值电流控制模式中斜坡补偿电路的设计.电力电子技术,2001,35(3):35-38
[24]高原,邱新芸,汪晋宽.峰值电流控制开关电源斜坡补偿的研究.仪器仪表学报,2003,24(4):118-120
[25]来新泉,周丽霞,陈富吉.升压型Dc-DC转换器中的动态斜坡补偿电路设计.微电子学,第35卷第4期,2005年8月
[26]R.B.Ridley.A new,continuous-time model for current-mode control,IEEE Trans.Power Elecron.Vol.6:271-280,April 1991
[27]F.Dong,Tan R.D.A unified model for current programmedconverter.IEEETrans.PowerElecron,July 1995,Vol.10,No.4:397-408
[28]Bryant.B,Kazimierczuk.M.K.Sample and hold effect in PWM DC-DC converters with peak current-mode control Circuits and Systems.2004.ISCAS '04.Proceedings of the 2004International Symposium on Volume 5,23-26 May 2004 Page(s):V-860-V-863
[29]Dixon.Closing the Feedback Loop.Unitrode Power Supply Design Seminar Manual-500:C1-1-1-31,1986
[30]Arbetter.B,Maksimovic.D.DC-DC converter with fast transient response and high efficiency for low-voltage microprocessor loads.Applied Power Electronics Conference and Exposition,1998.APEC'98.Conference Proceedings 1998,Thirteenth Annual Volume 1,15-19 Feb.1998Page(s):156-162 vol.1
[31]Rais Miftakhutdinov.Analysis and Optimization of Synchronous Buck Converter at High Slew-Rate Load Current Transients.Power Electronics Specialists Conference,2000.PESC 00.2000 IEEE 31 st Annual Volume 2,18-23 June 2000 Page(s):714-720 vol.2
[32]Lioyd H,Dixon.Current-mode control of switching power supply,www.ti.eom
[33]Redl.R,Erisman.B.P,Zansky.Z.Optimizing the load transient response of the buck converter.Applied Power Electronics Conference and Exposition,1998.APEC'98.Conference Proceedings 1998,Thirteenth Annual Volume 1,15-19 Feb.1998 Page(s):170-176 vol.1
[34]邹雪城,邵轲,郑朝霞.开关电源芯片中过温保护技术的研究与实现.微电子学与计算机,2006,23(7):193-194