用升压型IC实现降升压DCDC转换器

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基于升降压电路的双向DC-DC变换电路

基于Buck-Booost电路的双向DC-DC变换电路目录1系统方案 (4)1.1 DC-DC双向变换器模块的论证与选择 (4)1.2 测控电路系统的论证与选择 (4)2 系统理论分析与计算 (4)2.1 双向Buck-BOOST主拓电路的分析 (4)2.2 电感电流连续工作原理和基本关系 (5)2.3 控制方法与参数计算 (6)3 电路与程序设计 (7)3.1 电路的设计 (7)3.1.1 系统总体框图 (7)3.1.2 给电池组充电Buck电路模块 (7)3.1.3 电池放电Boost升压模块 (8)3.1.4 测控模块电路原理图 (8)3.1.5 电源 (9)3.2 程序设计 (9)4 测试方案与测试结果 (15)4.1 测试方案 (15)4.2 测试条件与仪器 (15)4.3 测试结果及分析 (15)4.3.1 测试结果(数据) (15)4.3.2 测试分析与结论 (16)摘要双向DC/DC变换器（Bi-directional DC-DC Converter，BDC）是一种可在双象限运行的直流变换器，能够实现能量的双向传输。

随着开关电源技术的不断发展，双向DC/DC变换器已经大量应用到电动汽车、太阳能电池阵、不间断电源和分布式电站等领域，其作为DC/DC变换器的一种新的形式，势必会在开关电源领域上占据越来越重要的地位。

由于在需要使用双向DC/DC变换器的场合很大程度上减轻系统的体积重量及成本，所以具有重要研究价值。

既然题目要求是作用于可充电锂电池的双向的DC-DC变换器，肯定包括降压、升压、电压可调、恒流、等要求。

考虑到题目对效率的要求，我们选择降压Buck电路，升压Boost电路，并用反馈电路和运放电路来实现电压可调和恒流等要求，通过一系列的测试和实验几大量的计算，基本上能完成题目的大部分要求。

关键词：双向DC/DC变换器；双向Buck-Boost变换器；效率；恒流稳压1系统方案本系统主要由DC-DC双向变换器模块、测控电路模块及辅助电源模块构成，分别论证这几个模块的选择。

dc-dc变换原理

dc-dc变换原理
DC-DC变换器是一种电子设备，用于将直流（DC）电压转换为另一种直流电压。

这种转换器在许多电子设备中都有广泛的应用，例如在电源适配器、电动汽车、太阳能系统和通信设备中都可以看到它们的身影。

DC-DC变换器的工作原理基于电感和电容的原理，通过精确控制开关管的导通和截止来实现输入电压到输出电压的变换。

DC-DC变换器的基本工作原理是利用电感和电容储存和释放能量，从而实现电压的升降。

当输入电压施加到变换器上时，开关管周期性地开关，这导致电感和电容中的能量储存和释放。

通过调整开关管的占空比和频率，可以实现对输出电压的精确控制。

在一个典型的升压型DC-DC变换器中，当开关管导通时，电流会通过电感和负载，从而储存能量。

当开关管截止时，电感中的储能会释放，从而提供给负载。

通过控制开关管的导通和截止时间，可以实现输出电压的精确控制。

相比于线性稳压器，DC-DC变换器具有更高的效率和更小的体积。

这使得它们在需要高效能转换和对电源体积要求严格的场合中
得到广泛应用。

总之，DC-DC变换器是一种非常重要的电子设备，它通过精确控制电感和电容的能量储存和释放，实现了输入电压到输出电压的精确变换。

在现代电子设备中，它们的应用已经变得非常普遍，为我们的生活带来了诸多便利。

dc升压芯片

dc升压芯片DC升压芯片是一种将直流电压升高的电子元件，被广泛应用于各种电源供应系统中。

在这篇文章中，我将介绍DC升压芯片的原理、特点和应用领域。

首先，我们来看一下DC升压芯片的原理。

DC升压芯片通过控制开关管的开关状态，实现对输入电压进行变换。

通常情况下，DC升压芯片采用开关型稳压技术，即将输入电压通过开关管控制在一定的占空比下，通过电感储能并通过输出电容进行平滑，从而达到升压的效果。

DC升压芯片的特点之一是高效率。

由于开关型稳压技术的特点，DC升压芯片可以实现高效率的升压转换。

相对于线性升压电路，DC升压芯片的效率更高，能够更好地满足工程设计对能源的管理需求。

其次，DC升压芯片的特点之二是可调性。

DC升压芯片可以通过调整输入输出电压比，实现对电压的精确控制。

这种可调性使得DC升压芯片在许多应用中非常有用，例如太阳能充电器、燃料电池电源和LED照明等。

除了高效率和可调性，DC升压芯片还具有其他一些特点。

例如，DC升压芯片通常具有较低的电磁干扰（EMI）和较高的抗干扰能力。

这些特点使得DC升压芯片在电磁环境较恶劣的设备中更加稳定可靠。

在实际应用中，DC升压芯片有着广泛的应用领域。

首先是电子产品领域，例如移动设备和便携式电子设备，它们通常需要一个输出电压比输入电压高的电源系统，以满足电路的要求。

其次是新能源领域，例如太阳能、风能和燃料电池等，这些能源系统的输出电压往往需要经过升压转换才能应用于实际设备。

此外，DC升压芯片还可以用于LED照明和汽车电子等领域。

总结一下，DC升压芯片是一种将直流电压升高的电子元件，通过控制开关管的开关状态实现对输入电压的变换。

它具有高效率、可调性和抗干扰能力强的特点，被广泛应用于电子产品和新能源领域。

用升压型DCDC做sepic升降压电路经验

用升压型DCDC做sepic升降压电路经验摘要：有很多网友都试验过用升压DCDC做自动升降压sepic电路，都以烧毁器件告终，本文阐述了一种烧毁器件的机理，希望网友门注意。

用TD8208做sepic电路，试图达到如下需求：1.输入是带充电器的锂电池电路，有USB外接电源时，自动用外接5V电源，否则用锂电池电源，故输入电压范围为2.6V-5.2V，其中锂电池供电时电压范围是2.6V-4.2V。

2.输出为3.3V或4.1V。

sepic电路拓扑：实际电路：TD8208(兼容替代型号CE8303/FP6291/MT3608/STI3508/SY7152/SY7208)的典型应用是boost电路，从datasheet中截取如下图，要修改为满足需求的sepic电路需要将下图中红叉位置断开，串入一个电容，再对地接一个电感，如上图中的C1和L2.同时需要修改R2。

R2为150K时，输出电压为3.5V左右。

试验结果：当输入电压从2.6V开始上升，步进0.1V，在低于4V时，输出电压一直维持在3.5V，非常稳定，但当电压上升到4V以上时，输入电流立即剧增，若输入无限流装置芯片立即损坏。

结论是电路末达到设计要求。

原因分析：对比测试TD8208在标准boot模式下LX端子的波形，发现波形尖峰顶部始终没有超过8V，而在sepic模式下，在输入电压末达到4V左右时就几乎达到8V，且顶部平坦，当电压继续升高时，会继续升高，随即产生很大的输入电流，估计是内部保护动作了。

标准boot模式下LX端子的波形查阅datashee发现：TD8208的LX端子电压最大为7V，估计厂家是在内部做了保护，估计是这个保护电压对电路产生了影响。

分析sepic电路结构，发现LX端子电压要比标准boost电路时高。

内部MOS管导通时内部MOS管断开时可以看到，内部MOS管断开时，LX电压是L1上的电压+L2上的电压，而L2的电压是C1在MOS管导通时充的，故LX端电压基本上是2Vo。

使用 LM3578A 的升压降压DC-DC转换电路宽电压输入

Application ReportSNVA035B–November1999–Revised April2013 AN-1066Low Cost Boost Converters Using LM3578AABSTRACTThe LM3578A integrated circuit is a switching regulator with all the power,control,and protection features.It operates over a wide input voltage range.This together with its low-cost makes it a very popular choice for use in switching regulators.This application report presents several low-cost boost converter circuits developed using the LM3578A switching regulator.The operation and the design of the boost converter is also discussed in detail.Contents1Introduction (2)1.1Modes of Operation (2)1.2Continuous Versus Discontinuous Mode (3)2Selection of Boost Power Stage Components (3)2.1Selection of the Boost Inductor (3)2.2Selection of Power Switch (4)2.3Selection of the Output Capacitor (4)2.4Selection of the Input Capacitor (5)2.5Selection of the Output Diode (5)3Low-Cost Boost Converters (5)3.1Voltage Doubler Circuit (5)3.2Boost Converter for Wide Band Tuners (6)3.3Low-Cost Boost Circuit for I/O Cards (7)4Summary (9)5References (9)Appendix A PCB Layout (10)List of Figures1Basic Boost Topology (2))Waveforms (2)2Inductor Current(iL3Low-Cost Voltage Doubler Circuit (6)45V to27V Boost Converter (7)5Low-Cost Boost Converter (8)6PCB Layout for the Circuits Shown in and(Scale:2:1) (10)7PCB Layout for the Circuit Shown in(Scale:2:1) (11)List of Tables1Parts List (6)2Parts List (7)3Parts List (9)All trademarks are the property of their respective owners.Introduction 1IntroductionThe boost or step-up converter converts a DC voltage to a higher DC voltage.Figure1shows the basic boost topology.When the switch software is turned on,energy is stored in the inductor L and the inductorcurrent iL ramps up at a slope determined by the input voltage.Diode D is off during this period.Once theswitch,SW,turns off,diode D starts to conduct and the energy stored in the inductor is released to the load.Current in the inductor ramps down at a slope determined by the difference between the input and output voltages.1.1Modes of OperationBased on the amount of energy that is delivered to the load during each switching period,the boostconverter can be classified into continuous or discontinuous conduction mode.If all the energy stored in the inductor is delivered to the load during each switching cycle,the mode of operation is classified as discontinuous conduction mode(DCM).In this mode,the inductor current ramps down all the way to zero during the switch off-time.If only part of the energy is delivered to the load,then the converter is said to be operating in continuous conduction mode(CCM).Figure2shows the inductor current waveforms for all the modes of operation.The mode of operation is a fundamental factor in determining the electrical characteristics of theconverter.The characteristics vary significantly from one mode to the other.Figure1.Basic Boost TopologyFigure2.Inductor Current(iL)Waveforms Selection of Boost Power Stage Components1.2Continuous Versus Discontinuous ModeBoth modes of operation have advantages and disadvantages.The main disadvantage in using CCM is the inherent stability problems (caused by the right-half-plane zero and the double pole in the small-signal control to output voltage transfer function).However,the switch and output diode peak currents are larger when the converter is operating in discontinuous rger peak currents necessitate using power switch and output diode with larger current and power dissipation rger peak currents also force the designer to use larger output capacitors.The larger peak currents also cause greater EMI/RFI problems.The mode of operation can be selected by the user.For very low load currents,discontinuous mode is preferred over continuous mode.If the load current requirements are high,then in order to minimize the peak currents and the associated problems,continuous mode is preferred.Two of the circuits presented in Section 3have very low load current requirements.Hence,they have been selected to operate indiscontinuous mode.The third circuit has very high peak current requirements and is selected to operate in continuous mode.2Selection of Boost Power Stage ComponentsThe boost converter design involves the selection of the inductor,the input and output capacitors,the power switch (included in the LM3578A),and the output diode.In order to select these components,it is necessary to know the duty cycle range and the peak currents.Knowing the maximum and minimum input voltages,the output voltage,and the voltage drops across the output diode and the switch,the maximum and minimum duty cycles are calculated.Next,the average inductor current can be estimated from the load current and duty cycle.Now,assuming the peak-to-peak inductor current ripple to be certain percentage of the average inductor current ripple,the peak inductor current can be estimated.The inductor value can be calculated using the ripple current,switching frequency,input voltage,and duty cycle information.Finally,it is necessary to establish the boundary condition,that is,the critical value of the inductor that the converter will operate in discontinuous mode.Once the inductor value has been chosen and the peak currents have been established,the other components can be selected very easily.The following paragraphs outline the selection of the boost power stage components,in a step-by-step approach.2.1Selection of the Boost InductorStep 1:Given the maximum and minimum input voltages,the maximum and minimum duty cycles can calculated using Equation 1and Equation 2:(1)(2)In Equation 1and Equation 2,V O is the output voltage,V d is the forward voltage drop of the output diode D,and V ce(sat)is the on state voltage of the switch,SW.V in(max)and V in(min)are the maximum and minimum input voltages,respectively.Step 2:The average inductor current (maximum)can be calculated using the output current,I O as shown in Equation 3:(3)Step 3:Assume the peak-to-peak inductor current ripple,Δi L to be a certain percentage of the average inductor current calculated in Equation 3.The peak inductor current is then given by:(4)Selection of Boost Power Stage Components Step 4:Knowing the switching frequency,f s the required inductance value can be selected using Equation 5:(5)Step 5:Calculate the boundary condition,that is,the minimum inductance required to operate the inductor in continuous mode.At the boundary between CCM and DCM modes of operation,the peak inductor current,I p is same as the peak-to-peak inductor current ripple,Δi L ,as shown in Figure 2.Hence,the average inductor current is given by:(6)Using Equation 3and Equation 6(7)The critical value of the inductance to maintain the converter in continuous mode of operation,derived from Equation 5and Equation 7is given by:(8)Using an inductance value lower than the critical value will result in discontinuous mode of operation.It can also be observed from Equation 5Equation 8that increasing the switching frequency helps in reducing the size of the inductor.2.2Selection of Power SwitchThe power switch is internal to the LM3578A.In general ,it is necessary to ensure that the estimated peak switch current (which is nothing but the peak inductor current,I p calculated in Equation 8)does not exceed the rated current of the switch.It is also necessary to ensure that the off-state voltage rating of the switch is never exceeded.The internal transistor in the LM3578A switching regulator is rated for a peak current of 750mA.The off-state sustaining voltage of the internal transistor is 50V.2.3Selection of the Output CapacitorIn the boost converter,the instantaneous value of currents entering and exiting the output capacitor is very high,since there is no inductive element between the output diode and the capacitor.This high current flows through the equivalent series resistance (ESR)and equivalent series inductance (ESL)of thecapacitor.ESR increases the capacitor temperature and increases ripple voltage.ESL adds sharp spikes to the ripple voltage waveform.Hence,it is desired to use output capacitors with very low ESR and ESL.The peak-to-peak output ripple voltage,ΔV O ,is given by:(9)where I Omax is the maximum output current.The output capacitor,C O can be selected using Equation 9.It should be noted that the ripple voltage due to the ESR,(R esr )is dominant in Equation 9.Also,ESL adds sharp spikes over the ripple voltage given by Equation 9.The ESR of the selected capacitor can be determined from the manufacturer catalogs or by actual bench measurement.If the value of the ripple exceeds the desired ripple voltage,then there are two choices:paralleling two or more capacitors to lower the effective ESR and ESL,or using a secondary LC filter.In general,low values of ESR are achieved by using large value capacitors or by paralleling smaller value capacitors.NOTE:Tantalum capacitors are known to have very low ESR.But they are expensive whencompared to electrolytic capacitors. Low-Cost Boost Converters2.4Selection of the Input CapacitorIn boost switching regulators,triangular ripple current is drawn from the supply voltage due to theswitching action.This appears as noise on the input line.This problem is less severe in boost converter due to the presence of inductor in series with input line.Select the input capacitor for:(10)From Equation 10,it can be observed that the rms current value is very low.Hence,a very small value capacitor is sufficient for boost converters.2.5Selection of the Output DiodeAs in all switching power supplies,two factors govern the choice of output rectifier:the forward voltage drop,V F ,and the reverse recovery time,t rr .V F determines the forward conduction loss and should be as low as possible.The reverse recovery time of the diode (and also the forward recovery time)should be as low as possible for minimizing the switching losses and RFI problems.Schottky rectifiers have very low forward voltage drops and reverse recovery times.The maximum reverse bias voltage on the output rectifier is given by:V r =V o −V ce(sat)(11)Select a Schottky diode satisfying the reverse voltage and peak current ratings given by Equation 4Equation 11,respectively.3Low-Cost Boost ConvertersThis section presents several low-cost boost circuits based on the LM3578A switching regulator.The LM3578A IC is a switching regulator featuring an internal comparator,oscillator,protection circuitry and a transistor.This IC operates from supply voltages ranging from 2V to 40V.This wide supply voltage range,together with its low cost makes it very popular.The transistor internal to LM3578A can handle currents only up to 750mA.However,for higher load current requirements,this internal transistor can be used to drive an external transistor with higher current rating such as the npn transistor,D44C3A.3.1Voltage Doubler CircuitFigure 3shows a low-cost voltage doubler circuit used typically in the RF card of a cable modem .This converter uses the LM3578A switching regulator for performing the required power conversion.Theinductor and other power stage components are selected using the procedure discussed in Section 2.The converter specifications are as follows:Input Voltage,V IN =12V Output Voltage V OUT =24V Load Current I L =10mA (max.)Switching Frequency,f s =100kHzSince the load current requirements are very low,this converter is chosen to operate in discontinuous conduction mode.The output voltage is maintained at 24V by the feedback network consisting of theresistors,R f1and R f2.The reference pin (pin 1)is set at 1V using these resistors.Capacitor C IN2is needed to ensure low noise at the input.The switching frequency is set by using the timing capacitor C T .Choosing a value of 680pF for C T sets the switching frequency at 100kHz.Capacitor C 1(typically between 10-25pF),together with the feedback resistors (R F1and R F2),is used for compensation.For more details on the choice of the above components,see the LM2578A/LM3578A Switching Regulator Data Sheet (SNVS767).Low-Cost Boost Converters Figure 3.Low-Cost Voltage Doubler CircuitTable 1.Parts ListDesignatorValue/RatingDescriptionIC1—LM3578M,Switching Regulator D 40V,0.5A MBR0540T1,Output DiodeL 470µH,60mA Boost Inductor C IN147µF,16V Input Capacitor C IN20.1µF,50V Input Capacitor (Ceramic)C OUT 22µF,35VOutput Capacitor R F1100k Feedback Resistor R F25k Feedback Resistor C F 22pF Feedback CapacitorC T680pFTiming Capacitor,Sets the Switching Frequency3.2Boost Converter for Wide Band TunersFigure 4shows a 5V to 27V boost converter used typically to create a high voltage for wide band tuners.Wide band cable and DSS tuners require about 27V at 5mA load current to bias the VCO varactor.The converter specifications are as follows:Input Voltage,V IN =5V Output Voltage,V OUT =27V Load Current I L =20mA (max.)Switching Frequency,f s =90kHz Input Ripple Voltage:17mV Output Ripple Voltage:58mVThe design of this circuit is very straightforward and is very similar to the design of the voltage doubler circuit discussed above.As in previous case,since the load current requirements are very low,thisconverter is chosen to operate in discontinuous conduction mode.The feedback resistors (R F1and R F2),the timing capacitor,C T and the compensation capacitor,C C are chosen in the same way.In order toensure low noise at the input,it is essential to add a high-frequency ceramic capacitor C IN2at the input rail,as shown in Figure 4. Low-Cost Boost ConvertersFigure4.5V to27V Boost ConverterTable2.Parts ListDesignator Value/Rating DescriptionIC1—LM3578M,Switching RegulatorD40V,0.5A MBR0540T1,Output DiodeL100µH,100mA Boost InductorC IN147µF,10V Input CapacitorC IN20.1µF,10V Input Capacitor(Ceramic)C OUT22µF,35V Output CapacitorR F1130k Feedback ResistorR F25k Feedback ResistorC F22pF Feedback CapacitorC T820pF Timing Capacitor,Sets the Switching Frequency3.3Low-Cost Boost Circuit for I/O CardsFigure5shows a low-cost boost converter that converts a3.3V input to5V at600mA load current.This circuit is typically used in I/O cards.Converter Specifications:Input Voltage,V=3.3V(±10%)inOutput Voltage=5V(±5%)Output Current=0mA–600mAEfficiency=80%The maximum and minimum duty cycles calculated using Equation1and Equation2are equal to0.52 and0.4,respectively.The average inductor current calculated using Equation3is:(12)Low-Cost Boost Converters Assuming the peak-to-peak ripple current to be 50%of the average inductor current,the peak current calculated using Equation 4is equal to:(13)The peak current calculated above is very much higher than the rated current of the internal switch in the LM3578A.Hence,it is necessary to use an external transistor or a FET.The selected external switchshould be capable of handling the high peak currents.The internal transistor in LM3578A can handle up to 750mA.So the current gain of the external transistor should be sufficient at the peak primary current.The off state voltage rating,V CE ,of the transistor should be at least 10V.One npn transistor meeting these requirements is D44C3A.The current gain (h fe )of this transistor at the peak current of 1.563A is about 50.So the maximum current that the internal transistor needs to provide is equal to 1.563/50=31mA,which is very much less than the rated current of the internal transistor.The circuit shown in Figure 5performs the required conversion using LM3578A and D44C3A npntransistor.The power stage components are selected using the procedure discussed in Section 2.From the above calculations,it can be seen that the peak current requirements are very high.Hence,this converter is chosen to operate in continuous conduction mode.The boost converter operating incontinuous mode has inherent stability problems (due to the right half plane zero and the double pole in the small-signal control to output transfer function).Hence,additional compensation is needed in thecontrol loop.This additional compensation is provided by the capacitor C C1(typically around 1nF)and the resistor R C1(typically between 100k and 200k).The current limiting in this circuit is activated whenever pin 7is pulled 110mV above the ground.The voltage across the current sense resistor,R sn is sensed in order to prevent excessive current through the external switch.The value of R sn is given by:(14)where I lim is the desired current limit set point.As an example,for the circuit shown in Figure 5,the peak switch current calculated above is 1.563A.Hence,if the desired current,I lim is set at 2A,then the value of the current-sense resistor will be R sn =0.110/2=0.055Ω.For cost reasons,the current-sense resistor can also be fabricated on a copper trace.Reference [1]describes the procedure for calculating the trace length and width.Figure 5.Low-Cost Boost Converter SummaryTable3.Parts ListDesignator Value/Rating DescriptionIC1—LM3578A Switching RegulatorQ15A,30V D44C3A,NPM TransistorD11A,40V Diode,1N5819L Lp-33µH,Ip-2.0A InductorC in220µF,6.3V Input CapacitorC o2x220µF,10V Output CapacitorR sn0.050Ω,1W Current Sense Resistor/Copper TraceR F140.06k,1/4W Feedback ResistorR F210k,1/4W Feedback ResistorR d11Ω,1/4W Base Drive ResistorR d2200Ω,1/4W Base Drive ResistorR f2000Ω,1/4W Resistor for Spike SuppressionC f1nF Capacitor for Spike SuppressionC T820pF Timing CapacitorC c22pF Compensation CapacitorC c11nF Compensation CapacitorR c1140k Compensation Capacitor4SummarySeveral low-cost boost converters,designed using the LM3578A switching regulator,were presented in this document.The circuits can be used in many different applications.The parts list has been provided for these circuits.Recommended layouts for these circuits were presented in Appendix A.The layout is very critical in these circuits.Pins1,2,and7of LM3578A are very noise sensitive.So these pins should be placed away from high frequency noise sources in the circuit.It is also necessary to have the feedback trace away from the inductor.In order to avoid false triggering of current limiting circuitry, filtering is very much essential for the sensed current.It is also important to note that the current sense voltage shut down level has very high tolerance.The voltage can vary from80mV to160mV(typicalvalue is100mV).This factor should be taken into consideration while selecting the current sense resistor.The compensation capacitor,CC connected between pins1and3should be typically between10to25ing a larger value for CC will start effecting the switching frequency.It is also necessary to note thatLM3578A can skip pulses at very low load currents when the minimum duty cycle of each pulse provides more energy than the load demands.Under these conditions,the controller internal to the LM3578A starts skipping pulses to maintain the output voltage at its correct value.This mode of operation is also known as burst mode.Although only three boost circuits have been presented,the design approach for other voltage and current levels is the same.5References1.AN-1055Low-Cost Multiple Output Flyback Converter for I/O Cards(SNOA383)2.LM2578A/LM3578A Switching Regulator Data Sheet(SNVS767)3.National Power ICs Databook Appendix A PCB LayoutFigure6.PCB Layout for the Circuits Shown in Figure3and Figure4(Scale:2:1) Appendix ANote:Copper trace is used as current sense resistor.Figure7.PCB Layout for the Circuit Shown in Figure5(Scale:2:1)11 SNVA035B–November1999–Revised April2013AN-1066Low Cost Boost Converters Using LM3578A Submit Documentation 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基于升降压电路的双向DC-DC变换电路

创作编号：GB8878185555334563BT9125XW创作者：凤呜大王*基于Buck-Booost电路的双向DC-DC变换电路目录1系统方案 (4)1.1 DC-DC双向变换器模块的论证与选择 (4)1.2 测控电路系统的论证与选择 (4)2 系统理论分析与计算 (4)2.1 双向Buck-BOOST主拓电路的分析 (4)2.2 电感电流连续工作原理和基本关系 (5)2.3 控制方法与参数计算 (6)3 电路与程序设计 (7)3.1 电路的设计 (7)3.1.1 系统总体框图 (7)3.1.2 给电池组充电Buck电路模块 (7)3.1.3 电池放电Boost升压模块 (8)3.1.4 测控模块电路原理图 (8)3.1.5 电源 (9)3.2 程序设计 (9)4 测试方案与测试结果 (15)4.1 测试方案 (15)4.2 测试条件与仪器 (15)4.3 测试结果及分析 (15)4.3.1 测试结果(数据) (15)4.3.2 测试分析与结论 (16)创作编号：GB8878185555334563BT9125XW创作者：凤呜大王*摘要双向DC/DC变换器（Bi-directional DC-DC Converter，BDC）是一种可在双象限运行的直流变换器，能够实现能量的双向传输。

由于在需要使用双向DC/DC变换器的场合很大程度上减轻系统的体积重量及成本，所以具有重要研究价值。

既然题目要求是作用于可充电锂电池的双向的DC-DC变换器，肯定包括降压、升压、电压可调、恒流、等要求。

升压型DC-DC转换电路工作原理

升压型DC-DC转换电路工作原理
升压型DC-DC转换电路工作原理
DC-DC转换器分为三类：Boost升压型DC-DC转换器、BUCK降压型DC-DC转换器以及Boost-BUCK升降压型DC-DC转换器三种，如果电路低压采用DC-DC转换电路，应该是Boost升压型DC-DC转换电路，并且输入电压、输出电压都是直流电压，而且输入电压比输出电压低，基本拓扑结构如图
工作原理分为两个步骤：
步骤一：如图回路1，开关管闭合（MOS管导通，相当于一根导线），这时输入的直流电压流过电感L。

二极管D1作用是防止电容C对地放电，同时起到续流作用。

由于输入的电压是直流电，因此电感上的电流以一定的比率线性的增加，这个比率跟电感因素有关，随着电感电流增加，电感里储存了一些能量。

步骤二：如图回路二，当开关管断开时候，由于电感的电流不能突变，也就是说流经电感L的电流不会马上变为零，而是缓慢的由充电完毕时的值变为零，这需要一个过程，而原来的电路回路已经断开，于是电感只能通过新电路放电，即电感开始给电容C2充电，电容两端电压升高，此时电压已经高于输入电压了，升压过程中，电容要足够大，这样在输出端就可以在放电过程中保持一个持续的电流，这两个步骤不断重复，在输出两端就得到高于输入电压的电压。

实际电路实例如下图
电感式DC-DC的升压器原理
电感是我们在变压器设计当中较长使用的一种元件，它的主要作用是把电能转化为磁能再存储起来。

需要注意的是，虽然电感的结构类似于变压器，但是其只有一个绕组。

本篇文章主要介绍了电感式DC-DC的升压器原理，并且本文属于基础性质，适合那些对电感的。

DCDC变换器的拓扑结构

DCDC变换器的拓扑结构
DCDC变换器是一种用于改变输入直流电压幅值和形态的电力电子器件，是电子设备中最常使用的电源变换器之一。

DCDC变换器可以实现高效、精确的电压转换，可以使用于降压、升压、升、降压等不同的应用场合中。

其主要包括降压型、升压型、升降压型等。

DCDC变换器主要由开关管、电容、电感等元件组成。

在DCDC变换器的工作流程中，电源电压先经过电源电感L进行滤波，经过稳压后进入开关管S。

当开关管S导通时，电源电压将由S导通的端口输出到负载上；当开关管S截止时，负载的电压将被电感和电容等能量存储元件储存，并带着负载的电流流向有源的元器件。

通过不断地开关、截止，使电力在电容、电感、负载、源等元器件之间转换，最后达到需要的电压值，从而实现了DCDC 变换器。

同时，在实际应用中，其实DCDC变换器有非常多的拓扑结构，因为事实上没有一种设计能适应所有的应用场合，所以厂家们设计出了多种不同形式的DCDC变换器。

每一种拓扑结构都有自己特别的优点与局限性。

1. 升压型。

升压型DCDC变换器，是将输入电压提升至输出电压。

其适用于驱动、通讯和其他高电压负载。

3. 拍断型。

拍断型DCDC变换器，最重要的功能是实现高速能量转换，因此适用于需要高速开关、恒定电流输出等的场合。

4. 变换匹配型。

变换匹配型DCDC变换器，不仅可以进行升压、降压，而且还能够将输入电压变换为其他电压值，灵活性高。

降低dcdc前端输入电压的方法

降低dcdc前端输入电压的方法
降低DC-DC转换器前端输入电压的方法有很多，以下是其中一些常用的方法：
1. 使用电阻分压器：在输入电压源串联一个电阻分压器，可以降低输入电压。

这种方法适用于输入电压较高的情况，但可能会浪费部分电能。

2. 使用变压器：使用变压器将输入电压降低到所需的电压值。

这种方法适用于需要多种电压等级的情况，但需要一个变压器，增加了电路的体积和成本。

3. 使用开关电源：开关电源是一种高效的降压方法，可以将输入电压降低到所需的电压值。

这种方法适用于需要较高输出电流的情况，但需要一个开关电源，增加了电路的复杂性和成本。

4. 使用线性稳压器：线性稳压器可以将输入电压降低到所需的电压值，同时保持电路的简单性和低成本。

这种方法适用于需要较低输出电流和较低输出电压的情况，但效率较低，可能会浪费部分电能。

需要注意的是，在选择降低DC-DC转换器前端输入电压的方法时，需要考虑电路的效率、体积、成本和输出电流等因素。

运用DC—DC降压／升压调节器调节电压

运用DC—DC降压／升压调节器调节电压【摘要】DC-DC开关转换器的作用是将一个直流电压高效地转换成其他电压值。

高效率DC-DC转换器采用三项基本拓扑结构：Buck（降压型）、Boost（升压型）和Buck/Boost（降压/升压型）。

Buck（降压转换器）用于产生较低的直流输出电压，Boost（升压转换器）用于产生较高的直流输出电压，Buck/Boost（降压/升压转换器）则用于产生小于、大于或等于输入电压的输出电压。

本文将重点介绍如何成功应用降压/升压DC-DC转换器。

【关键词】DC-DC；降压/升压；调节器1.概述如图1所示为采用单节的锂离子电池供电的典型低功耗系统。

电池的可用输出范围为放电以后的约3.0V到充满电时的4.2V。

系统IC需要1.8V、3.3V、和3.6V的电压，以实现最佳工作状态。

锂离子电池开始工作时的电压为4.2V，结束工作时的电压为3.0V，降压/升压调节器可以提供3.3V的恒定输出电压，而降压调节器或低压差（LDO）调节器则可在电池放电时提供1.8V的电压。

理论上，当电池电压高于3.5V时，可使用降压调节器或LDO产生3.3V电压，但当电池电压降至3.5V以下时，系统就会停止工作。

允许系统预先关闭会减少电池需要重新充电前的系统工作时间。

2.降压/升压调节器降压/升压调节器包括四个开关、两个电容和一个电感，如图2所示。

目前的低功耗、高效率降压/升压调节器在降压或升压模式下工作时，只要主动操作其中两个开关，就可以降低损耗、提高效率。

当VIN大于VOUT时，开关C断开，开关D闭合。

开关A和开关B的工作方式和在标准降压调节器中一样，如图3所示。

当VIN小于VOUT时，开关B断开，开关A闭合。

开关C和开关D的工作方式和在升压调节器中一样，如图4所示。

最困难的工作模式是当VIN处于VOUT±10%范围内时，此时调节器会进入降压/升压模式。

在降压/升压模式下，两种操作（降压和升压）会在一个开关周期内发生。

降压-升压转换器的工作原理

降压- 升压转换器，也称为升压型DC-DC 转换器，是一种能够在输入电压和输出电压之间实现双向电压变换的电源电路。

它主要由四个部分组成：输入滤波器、开关管、输出滤波器和电感器。

以下是降压- 升压转换器的工作原理：1. 输入滤波器：输入滤波器主要由电容和电感组成，用于过滤输入电压的噪声和纹波，确保输入电压的稳定性。

2. 开关管：开关管（如MOSFET）是降压- 升压转换器的核心部分，负责在输入电压和输出电压之间进行电压调节。

在开关管的控制下，输入电压的一部分能量被传递到输出电压，从而实现电压的升高。

3. 输出滤波器：输出滤波器主要由电容和电感组成，用于平滑输出电压的波形，降低输出电压的纹波和噪声。

4. 电感器：电感器在降压- 升压转换器中起到储能和传递能量的作用。

在开关管导通时，电感器储存输入电压的能量；在开关管断开时，电感器将储存的能量传递给输出电压。

降压- 升压转换器的工作过程如下：1. 开关管导通：当输入电压处于正向时，开关管导通，输入电压的一部分能量通过电感器储存，同时输出电压开始上升。

2. 开关管断开：当输入电压达到目标值时，开关管断开，此时电感器内的电流开始通过输出滤波器的电容放电，使输出电压保持稳定。

3. 输出电压调整：通过控制开关管的导通和断开时间，可以实现输出电压的调整。

当需要降低输出电压时，可以增加开关管的导通时间；当需要提高输出电压时，可以减少开关管的导通时间。

4. 循环过程：降压- 升压转换器在输入电压和输出电压之间不断进行电压变换，以满足不同应用场景的需求。

降压- 升压转换器通过开关管、电感器和输出滤波器的协同作用，实现了在输入电压和输出电压之间的双向电压变换，为各种电子设备提供了稳定的电源。

以升压型IC实现之降升压型直流转直流转换器介绍

以升压型IC实现之降升压型直流转直流转换器介绍
降升压型DC-DC转换器采用了升压型IC，也称为升压型稳压器。

这种IC内部有一个高效的开关，可以将输入电压逐周期地开关切换，以控制输出电压。

升压IC的主要工作原理是：当输入电压为低电平时，开关关闭，电感储能；当输入电压为高电平时，开关打开，通过电感释放储存的能量形成输出电压。

通过不断地进行开关和关闭操作，可以在输出端产生稳定的升压输出。

降升压型DC-DC转换器的主要优点是：
1.高效性能：采用升压型IC可以提供高效的电源转换，大大提高能量利用率，减少能量的浪费。

2.稳定输出：通过升压型IC的控制，可以实现稳定的输出电压，不受输入电压波动的影响。

3.小体积：升压型IC通常具有小尺寸和轻量化的特点，适合封装在紧凑的电子设备中。

4.方便调节：降升压型DC-DC转换器可以通过改变升压型IC的工作参数，如开关频率和占空比，来调节输出电压。

5.多功能性：降升压型DC-DC转换器可以实现多种输出电压的转换，可根据不同的应用需求设置不同的输出电压。

在实际应用中，降升压型DC-DC转换器有多种设计方案和拓扑结构，如升压型、降压型、升降压型和反激型等。

每种拓扑结构都有自己的特点和适用范围。

选取适合的降升压型DC-DC转换器方案需要考虑输入输出电压范围、传输效率、电源稳定性和成本等因素。

总之，降升压型DC-DC转换器利用升压型IC实现了高效、稳定的电源转换功能，广泛应用于各种电子设备中。

随着科技的不断进步，降升压型DC-DC转换器的性能和效率将继续提高，为电子设备提供高质量的电源转换解决方案。

以升压型IC实现之降升压型直流转直流转换器介绍

以升壓型IC實現之降升壓型直流/直流轉換器介紹將切換式穩壓器（Switching regulator）應用於可攜式裝置的電源設計變得愈來愈普遍。

對於以電池為動力的這類裝置而言，切換式穩壓器所具有效率高、體積小、重量輕的特點非傳統線性穩壓器可比。

例如在某些應用之中需要比電池額定電壓低的輸出電壓，此時可使用降壓型轉換器（Step-down converter）。

然而，當電池持續放電，電池的端電壓也會不斷下降。

為了盡量利用電池中所儲存的能量以延長使用時間，甚至會將電池使用至其端電壓小於輸出電壓。

因此，若能設計一具有降升壓功能的直流/直流轉換器將更能符合需求。

在接下來的文章之中，我們將介紹兩種以升壓型（Step-up）IC所實現之降升壓型直流/直流轉換器並比較其優缺點。

Single Ended Primary Inductor Converter（SEPIC）SEPIC電路是少數單極電路中可降升壓且輸出電壓極性與輸入電壓相同的電路之一。

如圖1（a），功率級電路的組成元件僅有一功率開關、一功率二極體、兩電感與三個電容。

元件數目雖少卻必須謹慎挑選才能設計出高效率的轉換器。

基本原理SEPIC電路的基本原理如下：穩態時電容C1上的電壓等於輸入電壓Vin，當開關S1導通，輸入電壓Vin與電容電壓VC1分別對電感L1、L2充電；當S1斷路，兩電感上所儲存的能量經由二極體D1輸出至負載；假設不計D1所造成的電壓降，則由電感的伏-秒（Volt-second）平衡方程式可求得輸出電壓與輸入電壓比為（1）其中d為開關S1的導通責任週期。

由（1）可看出只要調整開關S1的導通責任週期即可達成降升壓的目的。

圖2是理想的電壓電流波形。

設計實例今欲設計一以鋰離子電池為電源之SEPIC電路，輸出電壓欲維持在3.3V。

由於電池充飽電壓為4.2V，希望利用到電池電壓下降至2.8V，又電池充電時電路仍須正常工作，充電器輸出電壓為5.5V，表1為電路輸出入規格。

DC-DCCONVERTER（BUCKBOOSTBUCK-BOOST降壓、升壓、升降...

3.6~20V Adj(0.5~18V)
3A
FP6180
4.75~23V Adj(1.22~21V) 3A
AX3115
23V(Max) Adj(0.8)
3A
AX3102
4.5~23V Adj(0.8~18V)
3A
AX3107 / 8 20V(Max) Adj(0.8)
3A
ACT4070 4.5~30V Adj(1.3~28V)
2.0A
AX3114
4.5~23V Adj(1.22~18V) 2A
ACT4060 4.75~20V Adj(1.3~18V)
2A
ACT4065 4.75~28V Adj(1.3~26V)
2A
AX3001
4.5~24V Adj(1.23~19V) 2A
AX3007
4.5~40V Adj,12V,5V,3.3V 2A
Package
Replace
SOT23-5
SOT23-5
LTC3406,MP2104
SOT23-5
XC9226,XC9206
SOT23-5
-XC9226,XC9206
TQFN-16
SOT23-5
RT8008,ACT6906
SOT23-5
APS1006,APW7101
SOT23-5,SOT89-5
SOP-8/EP
Eff. SOT23-5 SOT23-5,SOT-89 SOT23-6,SOT89-5 MSOP-8 SOT23-5 SOP-8 MSOP-8 SOP-8 SOT23-5 SOP-8 SOP-8 SOP-8 SOP-8 SOP-8 SOP-8
Replace
RT9261,BL8530 RT9266 AIC1610