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SG3525A

本文涉及的是光明工程中一个课题的具体技术问题。

该课题的基本原理是逆变器由直流蓄电池供电,用太阳能为蓄电池充电,然后逆变电源输出220V、50Hz的交流电供用户使用。

在研制过程中,有时随机出现烧毁大功率管的现象,本文对这一现象给出了解决方案。

图1 SG3525A驱动MOS功率管电路图图2 逆变器工作过程中波形图（a）图3 (A)逆变器缓启动(B)逆变器硬启动SG3525A和逆变电源本课题研发的逆变器使用的核心器件是SG3525A,以下分别简述其基本性能和工作过程。

SG3525A基本性能SG3525A PWM型开关电源集成控制器包括开关稳压所需的全部控制电路,设有欠压锁定电路和缓启动电路可提供精密度为5V±1%的基准电压。

其开关频率高达200KHz以上,适合于驱动N沟道MOS功率管。

本课题使用SG3525A产生50Hz的准正弦方波,为逆变器提供输出功率信号,去推动N沟道MOS功率管90N08,如图1所示。

逆变器工作过程当SG3525A被加电后(12V)会输出两列50Hz反向的方波,其幅度为9V。

这两路方波分别进入G1、G2、G3、G4所示的四条支路(图1),经各电路分别调整后输出,输出脉冲序列如图2(B)所示。

最终调制合成为A、B 两端输出的交流方波。

其波形见图2(A)。

该50Hz的序列方波由A、B两端进入电力变压器DT。

通过变压器升压后由逆变器电源输出220V、50Hz交流方波。

根据市场的不同需求生产出200W、600W、800W各个系列的逆变电源。

问题的出现与解决逆变器在额定负载条件下能够长期运行,但是当进行负载切换时或者当外电路有严重扰动时,偶尔会发生大功率管MOSFET90N08烧毁的现象。

现以800W逆变器进行剖析。

缓启动：如图3(A)所示状态,同时满负载加在逆变器输出上,然后启动逆变器使之运行,一切正常工作。

硬启动：如图3(B)所示状态,即加满负载后再闭合开关K1强行硬启动。

这时就偶尔有大功率场效应管短路烧毁的现象发生,经分析发现当G3推动的大功率管TV3尚未完全关断时,G4开启了对应的大功率管TV4,如果TV3和TV4同时开通就会造成短路现象。

基于UC3525半桥式开关电源变换器的设计

毕业设计开题报告题目：基于UC3525半桥式开关电源变换器的设计专题：院（系）：班级：姓名：学号：指导教师：教师职称：黑龙江科技学院本科毕业设计开题报告题目基于UC3525半桥式开关电源变换器的设计来源工程实际1、研究目的和意义桥式拓扑开关管的稳态关断电压等于直流输入电压，而不像推挽、单端正激或交错正激拓扑那样为输入电压的两倍。

所以桥式拓扑结构广泛用于直接电网的离线式变换器。

而对于推挽等拓扑来说，两倍的电网整流电压将超过其开关管的安全耐压容限。

为此，输入网压为220V或更高的场合几乎都是采用桥式拓扑。

桥式拓扑的另一优点是，能将变压器初级侧的漏感尖峰电压钳位于直流母线电压，并将漏感储存的能量归还到母线，而不是消耗于电阻元件。

半桥式变压器开关电源与推挽式变压器开关电源一样，由于两个开关管轮流交替工作，相当于两个开关电源同时输出功率，其输出功率约等于单一开关电源输出功率的两倍。

因此，半桥式变压器开关电源输出功率很大，工作效率很高，经桥式整流或全波整流后，输出电压的电压脉动系数Sv和电流脉动系数Si都很小，仅需要很小的滤波电感和电容，其输出电压纹波和电流纹波就可以达到非常小。

2、国内外发展情况(文献综述)1955年美国罗耶（GH.Roger)发明的自激振荡推挽晶体管单变压器直流变换器，是实现高频转换控制电路的开端，1957年美国查赛（Jen Sen)发明了自激式推挽双变压器，１９６４年美国科学家们提出取消工频变压器的串联开关电源的设想，这对电源向体积和重量的下降获得了一条根本的途径。

到了１９６９年由于大功率硅晶体管的耐压提高，二极管反向恢复时间的缩短等元器件改善，终于做成了２５千赫的开关电源。

目前，开关电源以小型、轻量和高效率的特点被广泛应用于以电子计算机为主导的各种终端设备、通信设备等几乎所有的电子设备，是当今电子信息产业飞速发展不可缺少的一种电源方式。

目前市场上出售的开关电源中采用双极性晶体管制成的１００kHz、用ＭＯＳ－ＦＥＴ制成的５００kHz电源，虽已实用化，但其频率有待进一步提高。

3525 脉宽调制电路

致力于电源/音响产品芯片的开发与生产，以下是芯片目录：
电源产品用芯片：
型号产品说明
3525：脉宽调制电路，DIP-16
KA7500B（CP2026）：脉宽调制电路，DIP-16/SOP
UC3842：脉宽调制电路，DIP-8 /SOP
TL494（cp2026）：开关稳压器控制电路，DIP-16
TL431：双极型线性集成电路，TO-92，电源基准
LM324：四运放集成电路，DIP-14/SOP
LM358：双运算放大器电路，DIP-8/SOP
JRC4558：双运算放大器电路，DIP-8/SOP
LM393：双电压比较器电路，DIP-8
LM339：四电压比较器电路，DIP-14/SOP
7805：三端稳压（1.5A），TO-220
7812：三端稳压（1.5A），T0-220
7815：三端稳压（1.5A），T0-220
78L05：三端稳压（0.1A），TO-92
78L12：三端稳压（0.1A），TO-92
MC34063：单片双极型线性集成电路、车载充IC
785：移相触发调压
ULN2803：八路达林顿管阵列
ULN2003：七路达林顿管阵列
NE555：时计电路，DIP-8
LM1117：低压差线性稳压电路，SOT-223
音响产品用芯片：
型号产品说明
M54123：触漏电保护电路
TDA2822：双通道音频功放电路
TEA2025：双声道音频功放电路
TDA2030：双声道功放电路
TDA2003：音频功率放大器（FM/AM）以及其他音响芯片。

uc3525a(同SG3525)

FEATURESDESCRIPTIONBLOCK DIAGRAMINV NI OUTPUT BOUTPUT AVCOUTPUT BOUTPUT A VCOSC UC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008REGULATING PULSE WIDTH MODULATORS•8-V to 35-V Operation• 5.1-V Reference Trimmed to 1%The UC1525A/1527A series of pulse width modulator integrated circuits are designed to offer improved •100-Hz to 500-kHz Oscillator Range performance and lowered external parts count when •Separate Oscillator Sync Terminal used in designing all types of switching power •Adjustable Deadtime Control supplies.The on-chip +5.1-V reference is trimmed to 1%and the input common-mode range of the error •Internal Soft-Startamplifier includes the reference voltage,eliminating •Pulse-by-Pulse Shutdownexternal resistors.A sync input to the oscillator allows •Input Undervoltage Lockout With Hysteresis multiple units to be slaved or a single unit to be synchronized to an external system clock.A single •Latching PWM to Prevent Multiple Pulses resistor between the C T and the discharge terminals •Dual Source/Sink Output Driversprovides a wide range of dead-time adjustment.These devices also feature built-in soft-start circuitry with only an external timing capacitor required.A shutdown terminal controls both the soft-start circuitry and the output stages,providing instantaneous turn off through the PWM latch with pulsed shutdown,as well as soft-start recycle with longer shutdown commands.Please be aware that an important notice concerning availability,standard warranty,and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.PRODUCTION DATA information is current as of publication date.Copyright ©1997–2008,Texas Instruments IncorporatedProducts conform to specifications per the terms of the Texas Edited by Foxit ReaderCopyright(C) by Foxit Software Company,2005-2008For Evaluation Only.RECOMMENDED OPERATING CONDITIONS (1)UC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008These devices have limited built-in ESD protection.The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.These functions are also controlled by an undervoltage lockout which keeps the outputs off and the soft-start capacitor discharged for sub-normal input voltages.This lockout circuitry includes approximately 500mV of hysteresis for jitter-free operation.Another feature of these PWM circuits is a latch following the comparator.Once a PWM pulse has been terminated for any reason,the outputs will remain off for the duration of the period.The latch is reset with each clock pulse.The output stages are totem-pole designs capable of sourcing or sinking in excess of 200mA.The UC1525A output stage features NOR logic,giving a LOW output for an OFF state.The UC1527A utilizes OR logic which results in a HIGH output level when OFF.UCx52xAUNIT+V IN Supply voltage40V CCollector supply voltage 40VLogic inputs –0.3to +5.5Analog inputs–0.3to +V INOutput current,source or sink 500Reference output current 50mAOscillator charging current 5Power dissipation at T A =+25°C (2)1000mWPower dissipation at T C =+25°C (2)2000Operating junction temperature –55to 150Storage temperature range–65to 150°CLead temperature (soldering,10seconds)300(1)Values beyond which damage may occur.(2)See Thermal Characteristics table.(1)Range over which the device is functional and parameter limits are assured.2Submit Documentation Feedback Copyright ©1997–2008,Texas Instruments IncorporatedEdited by Foxit ReaderCopyright(C) by Foxit Software Company,2005-2008For Evaluation Only.THERMAL CHARACTERISTICSCONNECTION DIAGRAMS1234 5678161514131211109INV Input NI Input SYNC OSC OutputC T R TDischarge Soft StartV REF +V INOutput B V CGround Output A Shutdown CompensationJ or N PACKAGE (TOP VIEW)3212019910111213456781817161514Output B V C NC Ground Output ASYNC OSC OutputNC C T R TQ AND L PACKAGES(TOP VIEW)N I I n p u t I N V I n p u t N C C o m p e n s a t i o n S h u t d o w nV +V D i s c h a r g e S o f t S t a r t N C I NR E F NC − No internal connectionUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008over operating free-air temperature range (unless otherwise noted)PACKAGEθJA θJC J-1680-12028N-169045DW-1645-9025PLCC-2043-7534LCC-2070-8020PLCC-20,LCC-20DIL-16Copyright ©1997–2008,Texas Instruments Incorporated Submit Documentation Feedback3Edited by Foxit ReaderCopyright(C) by Foxit Software Company,2005-2008For Evaluation Only.ELECTRICAL CHARACTERISTICSf +1C T ǒ0.7R T )3RD ǓUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008+V IN =20V,and over operating temperature,unless otherwise specified,T A =T JPARAMETERTEST CONDITIONSMIN TYP MAX UNITREFERENCE UC152xA,UC252xA5.05 5.10 5.15Output voltage T J =25°C VUC352xA5.05.1 5.2Line regulationg V IN =8V to 35V 1020Load regulationg I L =0mA to 20mA 2050mVTemperature stability(1)Over operating range 2050UC152xA,UC252xA5.0 5.2Total output variation (1)Line,load,and temperature V UC352xA4.955.25Shorter circuit current V REF =0,T J =25°C 80100mA Output noise Voltage (1)10Hz ≤10kHz,T J =25°C 40200µVrms Long term stability (1)T J =125°C 2050mVOSCILLATOR SECTION (2)Initial accuracy (1)(2)T J =25°C 2%6%UC152xA,UC252xA0.3%1%Voltage stability (1)(2)V IN =8V to 35V UC352xA1%2%Temperature stability (1)Over operating range 3%6%Minimum frequency R T =200k Ω,C T =0.1µF 120Hz Maximum frequency R T =2k Ω,C T =470pF 400kHz Current mirror I RT =2mA1.72.0 2.2mA Clock amplitude (1)(2)3.0 3.5V Clock width (1)(2)T J =25°C0.30.5 1.0µs Syncronization threshold (1)(2)1.22.0 2.8V Sync input currentSync voltage =3.5V1.02.5mA ERROR AMPLIFIER SECTION (V CM =5.1V)UC152xA,UC252xA0.55mVInput offset voltage UC352xA210Input bias current 110µA Input offset current 1DC open loop gain R L ≥10M Ω6075dB Gain-bandwidth product (1)A V =0dB,T J =25°C12MHz DC transconductanc (1)(3)T J =25°C,30k Ω≤R L ≤1M Ω1.1 1.5mSLow-level output voltage 0.20.5V High-level output voltage 3.85.6Common mode rejection V CM =1.5V to 5.2V 6075dBSupply voltage rejection V IN =8V to 35V5060(1)These parameters,although ensured over the recommended operating conditions,are not 100%tested in production.(2)Tested at f OSC =40kHz (R T =3.6k Ω,C T =0.01µF,R D =0.Approximate oscillator frequency is defined by:(3)DC transconductance (g M )relates to DC open-loop voltage gain (A V )according to the following equation:A V =g M R L where R L is the resistance from pin 9to ground.The minimum g M specification is used to calculate minimum A V when the error amplifier output is loaded.4Submit Documentation Feedback Copyright ©1997–2008,Texas Instruments IncorporatedInv Input NI InputWCompto PWMComparatorUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008ELECTRICAL CHARACTERISTICS (continued)+V IN =20V,and over operating temperature,unless otherwise specified,T A =T JPARAMETERTEST CONDITIONSMINTYPMAXUNITPWM COMPARATOR Minimum duty-cycle 0%Maximum duty-cycle 45%49%Zero duty-cycle 0.70.9Input threshold (4)V Maximum duty-cycle3.3 3.6Input bias current (4)0.051.0µASHUTDOWN Soft-start current V SD =0V,V SS =0V 255080µA Soft-start low level V SD =2.5V0.40.7V Shutdown threshold To outputs,V SS =5.1V,T J =25°C 0.60.8 1.0Shutdown input current V SD =2.5V0.4 1.0mA Shutdown Delay (5)V SD =2.5V,T J =25°C 0.20.5µsOUTPUT DRIVERS (each output)(V C =20V)I SINK =20mA 0.20.4Low-level output voltage I SINK =100mA 1.0 2.0I SOURCE =20mA 1819V High-level output voltage I SOURCE =100mA 1718Undervoltage lockout V COMP and V SS =High 678V C OFF Current (6)V C =35V200µA Rise Time (5)C L =1nF,T J =25°C 100600nsFall Time(5)C L =1nF,T J =25°C 50300TOTAL STANDBY CURRENT Supply Current V IN =35V1420mA(4)Tested at f OSC =40kHz (R T =3.6k Ω,C T =0.01µF,R D =0Ω.(5)These parameters,although ensured over the recommended operating conditions,are not 100%tested in production.(6)Collector off-state quiescent current measured at pin 13with outputs low for UC1525A and high for UC1527A.UC1525A Error AmplifierCopyright ©1997–2008,Texas Instruments Incorporated Submit Documentation Feedback 5PRINCIPLES OF OPERATION AND TYPICAL CHARACTERISTICSClockF/F PWMOutput+V SUPPLYReturnUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008Figure 1.UC1525A Output Circuit (1/2circuit shown)Figure 2.Grounded Driver Outputs For Single-Ended SuppliesFor single-ended supplies,the driver outputs are grounded.The V C termainal is switched to ground by the totem-pole source transistors on alternate oscillator cycles.6Submit Documentation Feedback Copyright ©1997–2008,Texas Instruments IncorporatedReturnS a t u r a t i o n V o l t a g e − VOutput Current, Source or Sink − A+V SUPPLYReturnUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008PRINCIPLES OF OPERATION AND TYPICAL CHARACTERISTICS (continued)Figure 3.Output Drivers With Low Source ImpedanceThe low source impedance of the output drivers provides rapid charging of power FET input capacitance while minimizing external components.Figure 4.UC1525A Output Saturation Characteristics.Figure 5.Conventional Push-Pull Bipolar DesignIn conventional push-pull bipolar designs,forward base drive is controlled by R1–R3.Rapid turn-off times for the power devices are achieved with speed-up capacitors C1and C2.Copyright ©1997–2008,Texas Instruments IncorporatedSubmit Documentation Feedback 7+V SUPPLYReturnV REF R T C TWSYNCDISCHARGEGND UC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008PRINCIPLES OF OPERATION AND TYPICAL CHARACTERISTICS (continued)Figure 6.Low Power TransformersLow power transformers can be driven by the UC1525A.Automatic reset occurs during dead time,when both ends of the primary winding are switched to ground.Figure 7.UC1525A Oscillator Schematic8Submit Documentation Feedback Copyright ©1997–2008,Texas Instruments IncorporatedShutdown Options (See Block Diagram)− T i m i n g R e s i s t a n c e − k R T ΩCharge Time − m s− D e a d T i m e R e s i s t a nc e −R D ΩCharge Time − m sMinimum Recommended R T − k WM a x i m u m r e c o m m e n d e d RDf − Frequency − HzO p e n -L o o p V o l t a g e G a i n − d B°°°O p e n -L o o p P h a s eUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008PRINCIPLES OF OPERATION AND TYPICAL CHARACTERISTICS (continued)Since both the compensation and soft-start terminals (Pins 9and 8)have current source pull-ups,either can readily accept a pull-down signal which only has to sink a maximum of 100A to turn off the outputs.This is subject to the added requirement of discharging whatever external capacitance may be attached to these pins.An alternate approach is the use of the shutdown circuitry of Pin 10which has been improved to enhance the available shutdown options.Activating this circuit by applying a positive signal on Pin 10performs two functions;the PWM latch is immediately set providing the fastest turn-off signal to the outputs;and a 150-A current sink begins to discharge the external soft-start capacitor.If the shutdown command is short,the PWM signal is terminated without significant discharge of the soft-start capacitor,thus,allowing,for example,a convenient implementation of pulse-by-pulse current limiting.Holding Pin 10high for a longer duration,however,will ultimately discharge this external capacitor,recycling slow turn-on upon release.Pin 10should not be left floating as noise pickup could conceivably interrupt normal operation.All transitions of the voltage on pin 10should be within the time frame of one clock cycle and not repeated at a frequency higher than 10clock cycles.Oscillator Charge Time vs R T and C TOscillator Discharge Time vs R T C TFigure 8.Figure 9.Maximum Value R D vs Minimum Value R TError Amplifier Voltage Gain and Phase vs FrequencyFigure 10.Figure 11.Copyright ©1997–2008,Texas Instruments Incorporated Submit Documentation Feedback9REFUC1525A,UC1527A UC2525A,UC2527A UC3525A,UC3527ASLUS191C–FEBRUARY 1997–REVISED JANUARY 2008PRINCIPLES OF OPERATION AND TYPICAL CHARACTERISTICS (continued)Figure b Test Fixture10Submit Documentation Feedback Copyright ©1997–2008,Texas Instruments IncorporatedTAPE AND REEL INFORMATION*All dimensions are nominalDevicePackage Type Package Drawing Pins SPQReel Diameter (mm)Reel Width W1(mm)A0(mm)B0(mm)K0(mm)P1(mm)W (mm)Pin1Quadrant UC2525ADWTR SOIC DW 162000330.016.410.8510.8 2.712.016.0Q1UC3525ADWTRSOICDW162000330.016.410.8510.82.712.016.0Q1*All dimensions are nominalDevice Package Type Package Drawing Pins SPQ Length(mm)Width(mm)Height(mm) UC2525ADWTR SOIC DW162000346.0346.033.0 UC3525ADWTR SOIC DW162000346.0346.033.0IMPORTANT NOTICETexas Instruments Incorporated and its subsidiaries(TI)reserve the right to make corrections,modifications,enhancements,improvements, and other changes to its products and services at any time and to discontinue any product or service without notice.Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty.Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty.Except where mandated by government requirements,testing of all parameters of each product is not necessarily performed.TI assumes no liability for applications assistance or customer product design.Customers are responsible for their products and applications using TI components.To minimize the risks associated with 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3525芯片介绍

DN-36Design NoteUC1525B/UC1527B DEVICESComparison Summary to UC1525A/27A DevicesThe UC1525B and UC1527B devices are enhanced versions of the previous generation of UC1525A and UC1527A devices.They are pin-for-pin compatible and direct replacements for the “A”versions inalmost all applications. Significnt improvements have been made in the 5.1 V reference voltage and the output drivers as itemized in the tables below.PARAMETERNEW: UC1515B/27B OLD: UC1525A/27AREFERENCE VOLTAGE(max)Line Regulation (max) 5.062 V 5.05 v 5.138 V 5.15 v +/- 10 mV +/-20 mV Load Regulation (max)+/-15 mV +/-50 mV Temperature Stability (max)+/-30 mV+/-50 mV Total Output Variation (max) 5.036 V to 5.164 V 5.00 V to 5.20V Long Term Stability (max)+/-10 mV +/-50 mVTemperature Coefficient (typ)PWM OUTPUT SECTION 8 ppm/deg. CMinimum On-Time (typ)350 nS 600 nS Cross Conduction 30 nC150 nCSUPPLY CURRENTICC Increase (40 kHz to 400 kHz)15 mA (max)40 mA (typ) ESD PROTECTIONDischarge Withstand Voltage (typ)2 kV (typ all pins)no protectionUNITRODE CORPORATION7 CONTINENTAL BLVD. l MERRIMACK. NH 03054TEL. (603) 424-2410 l FAX (603) 424-34604-13IMPORTANT NOTICETexas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability.TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements.CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK.In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards.TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.Copyright © 1999, Texas Instruments Incorporated。

3525逆变器电路图

3525逆变器电路图
在中小容量变频电源的设计中，采用自关断器件的脉宽调制系统比非自关断器件的相控系统具有更多的优越性。

第一代脉宽调制器SG3525A应用于交流电机调速、UPS电源以及其他需要PWM脉冲的领域。

其外围电路可对串联谐振式逆变电源进行多功能控制，实现H桥式IGBT脉宽调制PWM信号的生成和逆变电源的保护功能，以及变频电源工作过程中谐振频率的跟踪控制。

控制电路（图4.1）的核心为PWM控制器SG3525A，用SG3525A发出的PWM脉冲，来控制逆变器VT1、VT4和VT2、VT3轮流导通，从而控制逆变电压和逆变频率。

图4.1中SG3525A的6脚连接电阻R，改变R的大小，这样就可调控SG3525输出的PWM 脉冲频率。

同时通过调节SG3525的9脚电压来改变输出脉宽。

3525逆变器电路图
反馈电路如上图4.1所示，当电流互感器从负载端感应出交流电流，通过桥式整流器把他转化为直流电，在滑动变阻器PR2上产生电压。

由滑动端输出的信号接到SG3525A的10脚上，当脚10电压大于0. 7V时，芯片将进行限流操作，当脚10电压超过1.4V时，将使PWM 锁存器关断，直至下一个时钟周期才能够恢复。

以下分别独立介绍感应加热电源控制电路各个组成部分的基本原理、功能及参数计算。

由SG3525组成的300W正弦波逆变电路图:。

SG3525A 中文资料

该SG3525A的脉宽调制器控制电路提供提高性能和降低外部元件数时实施了控制开关电源的所有类型。

片上5.1 V参考修剪成？1％的错误放大器的输入共模电压范围，包括参考电压，从而消除了对外部分压器的需求电阻。

在同步输入到振荡器使多个单位以苦练或一个单位可以同步到一个外部系统时钟。

广泛的死区时间可以由单个电阻器编程连接在CT和放电针。

这个装置还带有内置软启动电路，只需要一个外部定时电容器。

关断控制引脚同时软启动电路和输出级，瞬间又提供了通过脉宽调制锁存器脉冲关机，以及软启动回收与再关闭命令。

根据输出电压锁定抑制和不断变化的软启动电容时的VCC低于有名无实。

输出阶段的图腾柱设计能力的沉没并在200 mA的超额采购。

该SG3525A的输出级在功能的NOR为关闭状态低产出导致逻辑。

特点
8.0 V至35 V工作电压
v1.0的5.1％，边参考
100赫兹至400赫兹振荡器范围
独立的振荡器同步引脚
可调节死区时间控制
输入欠压锁定
锁定的PWM脉冲，以防止多重
脉冲鈭抌Ÿ鈭扨ulse关机
双源/接收器输出：400 mA峰值
铅鈭扚稀土元素包现已推出*
PIN CONNECTIONS
Inv. Input
Sync
OSC. Output
RT
Discharge
Soft-Start
Noninv. Input
CT
Compensation
Shutdown
Output A
VC
Output B
VCC
Vref
Ground。

KA3525A中文资料

KA3525A SMPS CONTROLLERVOLTAGE-MODE PWM CONTROLLERThe KA3525A is a monolithic integrated circuit that Included all ofthe control circuit necessary for a pulse width modulating regulator.There are a voltage reference, an error amplifier, a pulse widthmodulator, an oscillator, under-voltage lockout, soft start circuit, andoutput drivers in the chip.FEATURES•5V ä1% Reference•Oscillator Sync Terminal•Internal Soft Start•Deadtime Control•Under-Voltage LockoutORDERING INFORMATIONBLOCK DIAGRAM5.5K5.5K43KDevice Package Operating Temperature KA3525A16 DIP-30 ~ +85ÎKA3525AD16-SOP-225A-30 ~ +85Î16-DIP16-SOP-225A©1999 Fairchild Semiconductor CorporationRev. B控制电路所需的脉冲宽度调制调节器。

有一电压参考，一个误差放大器，脉宽调制器，振荡器，根据欠压锁定，软启动电路，以及输出驱动器在晶片内特征参考电压：5V+_1%振荡器同步终端内部软启动欠压锁存特征ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(V CC = 20V, T A = -35Î to + 85Î, unless otherwise specified)CharacteristicSymbol Value Unit Supply VoltageV CC 40V Collector Supply Voltage V C40V Output Current, Sink or Source I O 500mA Reference Output Current I REF 50mA Oscillator Charging Current I CHG(OSC)5mA Power Dissipation (T A = 25Î)P D 1000m/W Operating Temperature T OPR 0 ~ +70Î Storage TemperatureT STG -65 ~ +150Î Lead Temperature (Soldering, 10 sec)T LEAD+300ÎCharacteristicSymbolTest ConditionsMinTypMaxUnitREFERENCE SECTION Reference Output Voltage V REF T J = 25Î 5.05.1 5.2V Line Regulation L V REF V CC = 8 to 35V 920mV Load RegulationL V REF I REF = 0 to 20mA 2050mV Short Circuit Output Current I SC V REF = 0, T J = 25Î80100mA Total Output Variation (Note 1)L V REF Line, Load and Temperature4.955.25V Temperature Stability (Note 1)ST T 2050mV Long Term Stability (Note 1)STT J = 125Î, 1 KH RS2050mVOSCILLATOR SECTION Initial Accuracy (Note 1, 2)ACCUR T J = 25Îä3ä6% Frequency Change With Voltage L f/L V CCV CC = 8 to 35V (Note 1, 2)ä0.8ä2% Maximum Frequency f (MAX)R T = 2K `, C T = 470pF 400430KHz Minimum Frequency f (MIN)R T = 200K `, C T = 0.1s F60120Hz Clock Amplitude (Note 1, 2)V (CLK)34V Clock Width (Note 1, 2)t W(CLK)T J = 25Î0.30.61s s Sync Threshold V TH(SYNC) 1.22 2.8V Sync Input CurrentI I(SYNC)Sync = 3.5V 1.32.5mA输出电流参考输出电流ELECTRICAL CHARACTERISTICS(V CC = 20V, T A = -35Î to +85Î, unless otherwise specified)(Note)1. These parameters. although guaranteed over the recommended operating conditions, are not 100% tested in production2. Tested at f OSC =40 KHz (R T =3.6K, C T =0.01s F, R I = 0`)CharacteristicSymbolTest Conditions Min TypMaxUnitERROR AMPLIFIER SECTION (V CM = 5.1V)Input Offset Voltage V IO 1.510mV Input Bias Current I BAIS 110s A Input Offset Current I IO0.11s A Open Loop Voltage GainG VOR L 10M `6080dB Common Mode Rejection Ratio CMRR V CM = 1.5 to 5.2V 6090dB Power Supply Rejection Ratio PSRRV CC = 8 to 3.5V5060dBPWM COMPARATOR SECTION Minimum Duty Cycle D (MIN)0% Maximum Duty CycleD (MAX)4549% Input Threshold Voltage (Note 2)V TH1Zero Duty Cycle 0.70.9VInput Threshold Voltage (N0te 2)V TH2Max Duty Cycle 3.2 3.6V SOFT-START SECTION Soft Start CurrentI SOFT V SD = 0V, V SS = 0V255180s A Soft Start Low Level VoltageV SL V SD = 25V0.30.7V Shutdown Threshold VoltageV TH(SD)0.7 1.3 1.7V Shutdown Input Current I N(SD)V SD = 2.5V 0.31mA OUTPUT SECTIONLow Output Voltage I V OL I I SINK = 20mA 0.10.4V Low Output Voltage II V OL II I SINK = 100mA 0.052V High Output Voltage I V CH I I SOURCE = 20mA 1819V High Output Voltage IIV CH II I SOURCE = 100mA 1718VUnder Voltage Lockout V UV V 8 and V 9 = High 678V Collector Leakage CurrentI LKG V CC = 35V 80200s A Rise Time (Note 1)t R C L = 1s F, T J = 26Î80600nS Fall Time (Note 1)t F C L = 1s F, T J = 25Î70300nS STANDBY CURRENTSupply CuttentI CCV CC = 35V1220mA输入偏置电流输入失调电压开环电压增益共模抑制比电源抑制比最低占空比最大占空比输入阈值电压软启动电流软启动最低电压关机阈值电压关闭输入电流最低输出电流1欠压锁定集电极电流上升时间下降时间TEST CIRCUITTRADEMARKSACEx™CoolFET™CROSSVOLT™E 2CMOS TM FACT™FACT Quiet Series™FAST ®FASTr™GTO™HiSeC™The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks.LIFE SUPPORT POLICYFAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORTDEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROV AL OF FAIRCHILD SEMICONDUCTOR CORPORA TION.As used herein:ISOPLANAR™MICROWIRE™POP™PowerTrench™QS™Quiet Series™SuperSOT™-3SuperSOT™-6SuperSOT™-8TinyLogic™1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant intothe body, or (b) support or sustain life, or (c) whosefailure to perform when properly used in accordancewith instructions for use provided in the labeling, can be reasonably expected to result in significant injury to the user.2. A critical component is any component of a lifesupport device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Product Status DefinitionAdvance InformationPreliminary No Identification Needed Obsolete This datasheet contains the design specifications for product development. Specifications may change in any manner without notice.This datasheet contains preliminary data, andsupplementary data will be published at a later date.Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design.This datasheet contains final specifications. Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design.This datasheet contains specifications on a product that has been discontinued by Fairchild semiconductor.The datasheet is printed for reference information only.Formative or In DesignFirst ProductionFull ProductionNot In ProductionDISCLAIMERFAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY , FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.UHC™VCX™。

高效数控恒流源（UC3525）

高效数控恒流源（UC3525）基于UC3525的高效数控恒流源的设计摘要：研究了一种适合宽负载条件运行的有限双极性控制方法并配合饱和电感和隔直电容实现ZVZCS PWM的全桥变换器，分析了其工作过程及主开关器件实现ZVZCS的约束条件。

最后通过具体的功率实验．验证了该控制方法在较宽负载范围条件下实现软开关的能力。

关键词：有限双极性控制；零电压零电流开关；饱和电感；全桥变换器引言全桥移相ZVS变换器近年来得到了广泛关注，在中大功率的通讯电源和电力操作电源中得到广泛的应用。

然而，这种控制方法有以下几个明显的缺点。

(1)滞后臂开关管在轻载下将失去零电压开关功能；(2)为了实现滞后臂的ZVS，必须在电路中串联电感，这会引起占空比丢失，增人了原边电流定额；(3)原边存在较大环流，增加了系统通态损耗。

为了解决这些问题，人们针对IGBT拖尾电流大的特点义提出了全桥移相ZVZCS变换器。

其主要思路是超前臂实现ZVS，滞后臂实现ZCS，从而从根本上解决了原先全桥移相ZVS变换器中滞后臂零电压开关困难的问题。

由于不需要外加电感，占空比丢失问题随之解决，环流也大大减小。

实现滞后臂的ZCS目前主要有以下几种办法。

(1)副边有源箝位的ZVZCS方法，但增加了成本，并由于需要复杂的隔离驱动而降低了可靠性；(2)副边无源箝位和原边无源箝位；(3)利用IGBT的反向雪崩击穿电压；(4)原边串联饱和电感和隔直阻断电容。

但移相控制本身还有一个难以克服的缺点，即死区时间不好调整。

当负载较重时，由于环流大，超前臂功率管上并联的电容放电较快，因此实现零电压导通比较容易，但当负载较轻时，超前臂功率管上并联的电容放电很慢，超前桥臂的开关管必须延时很长时间才能实现ZVS导通。

传统的移相控制很难调整这个死区时间。

本文研究了一种名为有限双极性控制的控制方法，配合上面介绍的原边串联饱和电感和隔直电容的ZVZCS PWM全桥拓扑，可以在很宽的负载范围内实现超前臂的ZVS和滞后臂的ZCS。

控制芯片SG3525A

控制芯片SG3525ASG3525A的内部结构见图,由基准电压调整器、振荡器、误差放大器、比较器、锁存器、欠压锁定电路、闭锁控制电路、软起动电路、输出电路构成.(1)欠压锁定功能基准电压调整器受巧脚的外加直流电压的影响,当低于7V时,基准电压调整器的精度值就得不到保证,由于设置了欠压锁定电路,当出现欠电压时,欠压锁定功能使A端线由低电压上升为逻辑高电平,经过SG3525A的13脚输出为高电平,功率驱动电路输出至功率场效应管的控制脉冲消失,逆变器无电压输出.(2)系统的故障关闭功能集成控制器SG3525A内部的T3晶体管基极经一电阻连接10引脚.过流保护环节检测到的故障信号使10脚为高电平.由于T3基极与A端线相连.故障信号产生的关闭过程与欠电压锁定过程类似.在电路中,过流保护环节还输出一个信号到与门的输入端,当出现过流信号时,检测环节输出一低电平信号到与门的输入端,使脉冲消失,与SG 3525的故障关闭功能一起构成双重保护.(3)软起动功能软起动功能的实现主要由SG3525A内部的晶体管T3和外接电容C3及锁存器来实现的.当出现欠压或者有过流故障时,A端线高电平传到T3晶体管基极,T3导通为8引脚外接电容C3提供放电的途径.C3经T3放电到零电压后,限制了比较器的PWM脉冲电压输出,电压上升为恒定的逻辑高电平,PWM高电平经PWM锁存器输出至D端线仍为恒定的逻辑高电平,C3电容重新充电之前,D端线的高电平不会发生变化,封锁输出.当故障消除后,A端线恢复为低电平正常值,T3截止,C3由50μA电流源缓慢充电,C3充电对PWM和D端线脉冲宽度产生影响,同时对P1和P2输出脉冲产生影响,其结果是使P1和P2脉冲由窄缓慢变宽,只有C3充电结束后,P1和P2的脉冲宽度才不受C3充电的影响.这种软起动方式,可使系统主回路电机及功率场效应管承受过大的冲击浪涌电流.4.1.2芯片管脚及其功能介绍SG3525脉宽调制型控制器是美国通用电气公司的产品,作为SG3524的改进型,更适合于运用MOS管作为开关器件的DC/DC变换器,它是采用双级型工艺制作的新型模拟数字混合集成电路,性能优异,所需外围器件较少.它的主要特点是:输出级采用推挽输出,双通道输出,占空比0-50%可调, 每一通道的驱动电流最大值可达200mA,灌拉电流峰值可达500mA.可直接驱动功率MOS管,工作频率高达400KHz,具有欠压锁定、过压保护和软启动等功能.该电路由基准电压源、震荡器、误差放大器、PWM比较器与锁存器、分相器、欠压锁定输出驱动级,软启动及关断电路等组成,可正常工作的温度范围是0-700℃.基准电压为5.1 V士1%,工作电压范围很宽,为8V到35V.SG3525采用16端双列直插DIP封装,引脚图及各端子功能介绍如下:INV.INPUT(反相输入端1):误差放大器的反相输入端,该误差放大器的增益标称值为80db,其大小由反馈或输出负载来决定,输出负载可以是纯电阻,也可以是电阻性元件和电容元件的组合.该误差放大器共模输入电压范围是1. 5V-5. 2V.此端通常接到与电源输出电压相连接的电阻分压器上.负反馈控制时,将电源输出电压分压后与基准电压相比较.NI.NPUT(同相输入端2):此端通常接到基准电压16脚的分压电阻上,取得2. 5V的基准比较电压与INV. INPUT端的取样电压相比较.SYNC(同步端3):为外同步用.需要多个芯片同步工作时,每个芯片有各自的震荡频率,可以分别他们的4脚和3脚相连,这时所有芯片的工作频率以最快的芯片工作频率同步.也可以使单个芯片以外部时钟频率工作.OSC.OUTPUT(同步输出端4):同步脉冲输出.作为多个芯片同步工作时使用.但几个芯片的工作频率不能相差太大,同步脉冲频率应比震荡频率低一些.如不需多个芯片同步工作时,3脚和4脚悬空.4脚输出频率为输出脉冲频率的2倍.输出锯齿波电压范围为0. 6V到3. 5V. Cr(震荡电容端5):震荡电容接至5脚,另一端直接接至地端.其取值范围为0.001u F到0. 1 u F.正常工作时,在Cr两端可以得到一个从0.6V到3. 5V变化的锯齿波.(震荡电阻端6):震荡电阻一端接至6脚,另一端直接接至地端. 的阻值决定了内部恒流值对Cr充电.其取值范围为2K欧到150K欧和Cr越大充电时间越长,反之则充电时间短.DISCHA TGE RD(放电端7):Cr的放电由5、7两端的死区电阻决定.把充电和放电回路分开,有利于通过死区电阻来调节死区时间,使死区时间调节范围更宽.其取值范围为0欧到500欧.放电电阻RD和CT越大放电时间越长,反之则放电时间短.这样,SG3525A的振荡频率可由下面的公式进行计算:SOFTSTA TR(软启动8):比较器的反相端即软启动器控制端8,端8可外接软启动电容,该电容由内部的50uA恒流源充电.COMPENSA TION(补偿端9):在误差放大器输出端9脚与误差放大器反相输入端1脚间接电阻与电容,构成PI调节器,补偿系统的幅频、相频响应特性.补偿端工作电压范围为1. 5V到5. 2V.SHUTDOWN(关断端10):10端为PWM锁存器的一个输入端,一般在10端接入过流检测信号.过流检测信号维持时间长时,软起动端8接的电容C被放电.一般用法是将过流脉冲信号送至关闭控制端10脚,当脚10电压大于0. 7V时,芯片将进行限流操作,当脚10电压超过1.4V 时,将使PWM锁存器关断,直至下一个时钟周期才能够恢复.OUTPUT A, OUTPUT B(脉冲输出端11、14):输出末级采用推挽输出电路,驱动场效应功率管时关断速度更快.11脚和14脚相位相差180°,拉电流和灌电流峰值达200mA.由于存在开闭滞后,使输出和吸收间出现重迭导通.在重迭处有一个电流尖脉冲,起持续时间约为l00ns.可以在处接一个约0. lμf的电容滤去电压尖峰.GROUND(接地端12):该芯片上的所有电压都是相对于GROUND而言,即是功率地也是信号地.在实验电路中,由于接入误差放大器反向输入端的反馈电压也是相对与12脚而言,所以主回路和控制回路的接地端应相连.VC(推挽输出电路电压输入端13):作为推挽输出级的电压源,提高输出级输出功率.可以和15脚共用一个电源,也可用更高电压的电源.电压范围是4.5V-35V .+VIN(芯片电源端15):直流电源从15脚引入分为两路:一路作为内部逻辑和模拟电路的工作电压;另一路送到基准电压稳压器的输入端,产生 5.1士1%V的内部基准电压.如果该脚电压低于门限电压(Turn-off=8V),该芯片内部电路锁定,停止工作(基准源及必要电路除外)使之消耗的电流降至很小(约2mA).另外,该脚电压最大不能超过35V,使用中应该用电容直接旁路到GROUND端.VREF(基准电压端16):基准电压端16脚的电压由内部控制在5. 1 V土1%.可以分压后作为误差放大器的参考电压.。

uc2525a工作原理

uc2525a工作原理UC2525A是一种常用的电源管理集成电路，它的工作原理是通过控制开关管的导通和截止来实现直流-直流（DC-DC）转换。

在本篇文章中，我们将详细介绍UC2525A的工作原理和其在电源管理中的应用。

一、UC2525A的基本结构和功能UC2525A是一种双路PWM控制器，它主要由误差放大器、比较器、PWM逻辑控制电路、电流限制电路和反馈电路等组成。

它的主要功能是通过对控制信号的调节，实现DC-DC转换器的稳定输出。

二、误差放大器和比较器的作用UC2525A的误差放大器用于比较参考电压和反馈电压之间的差异，并将其放大。

比较器则用于将误差放大器的输出与三角波进行比较，产生PWM控制信号。

三、PWM逻辑控制电路的原理PWM逻辑控制电路是UC2525A中的核心部分，它通过对比较器输出信号的处理，控制开关管的导通和截止时间，从而调节输出电压。

在正常工作状态下，PWM逻辑控制电路会根据比较器输出信号的高低电平，确定开关管的导通和截止时间。

当比较器输出为高电平时，开关管导通，输出电压增加；当比较器输出为低电平时，开关管截止，输出电压减小。

通过不断调节导通和截止时间，PWM逻辑控制电路使得输出电压能够稳定在设定值。

四、电流限制电路的作用UC2525A还配备了电流限制电路，用于保护开关管和其他电路不受过大电流的损害。

当输出电流超过一定阈值时，电流限制电路会立即切断开关管的导通，从而保护电路的安全运行。

五、反馈电路的功能在DC-DC转换中，反馈电路用于采集输出电压信息，并将其与参考电压进行比较。

通过不断调节PWM逻辑控制电路的输出信号，反馈电路能够使输出电压稳定在设定值。

六、UC2525A的应用领域由于UC2525A具有工作稳定、可靠性高的特点，广泛应用于各种电源管理系统中。

例如，它可以用于DC-DC转换器、电池充电器、逆变器等电源管理设备中。

在DC-DC转换器中，UC2525A可实现从输入电源到输出电源的电压变换，并保持输出电压稳定。

FAIRCHILD UC3525A 数据手册

©2000 Fairchild Semiconductor InternationalRev. 5.0Features•5V ± 1% Reference •Oscillator Sync terminal •Internal Soft Start •Deadtime Control•Under-V oltage LockoutDescriptionUC3525A is a monolithic integrated circuit that Included all of the control circuit necessary for a pulse width modulat-ing regulator. There are a voltage reference, an error ampli-fier, a pulse width modulator, an oscillator, under-voltage lockout, soft start circuit, and output drivers in the chip.16-DIP1Internal Block DiagramUC3525ASMPS Controller查询UC3525供应商UC3525AAbsolute Maximum RatingsParameter Symbol Value Unit Supply Voltage V CC40V Collector Supply Voltage V C40VOutput Current, Sink or Source I O500mA Reference Output Current I REF50mA Oscillator Charging Current I CHG(OSC)5mA Power Dissipation (T A = 25°C)P D1000m/W Operating Temperature T OPR0 ~ +70°C Storage Temperature T STG-65 ~ +150°CLead Temperature (Soldering, 10 sec)T LEAD+300°CElectrical Characteristics(V CC = 20V, T A = -30°C to + 85°C, unless otherwise specified)Parameter Symbol Conditions Min.Typ.Max.Unit REFERENCE SECTIONReference Output Voltage V REF T J = 25°C 5.0 5.1 5.2V Line Regulation∆V REF V CC = 8 to 35V-920mV Load Regulation∆V REF I REF = 0 to 20mA-2050mV Short Circuit Output Current I SC V REF = 0, T J = 25°C-80100mA Total Output Variation (Note 1)∆V REF Line, Load and Temperature 4.95- 5.25V Temperature Stability (Note 1)ST T--2050mV Long Term Stability (Note 1)ST T J = 125°C ,1 KHR S-2050mV OSCILLATOR SECTIONInitial Accuracy (Note 1, 2)ACCUR T J = 25°C-± 3±6% Frequency Change With Voltage∆f/∆V CC V CC = 8 to 35V (Note 1, 2)-± 0.8±2% Maximum Frequency f(MAX)R T = 2KΩ, C T = 470pF400430-KHz Minimum Frequency f(MIN)R T = 200KΩ, C T = 0.1uF-60120Hz Clock Amplitude (Note 1, 2)V(CLK)-34-V Clock Width (Note 1, 2)t W(CLK)T J = 25°C0.30.61µs Sync Threshold V TH(SYNC)- 1.22 2.8V Sync Input Current I I(SYNC)Sync = 3.5V- 1.3 2.5mA2UC3525AElectrical Characteristics(V CC = 20V, T A = 0 to +85°C, unless otherwise specified)Parameter Symbol Conditions Min.Typ.Max.Unit ERROR AMPLIFIER SECTION (V CM = 5.1V)Input Offset Voltage V IO-- 1.510mV Input Bias Current I BIAS--110µA Input Offset Current I IO--0.11µA Open Loop Voltage Gain G VO R L ≥10MΩ6080-dB Common Mode Rejection Ratio CMRR V CM = 1.5 to 5.2V6090-dB Power Supply Rejection Ratio PSRR V CC = 8 to 3.5V5060-dB PWM COMPARATOR SECTIONMinimum Duty Cycle D(MIN)---0% Maximum Duty Cycle D(MAX)-4549-% Input Threshold Voltage (Note 2)V TH1Zero Duty Cycle0.70.9-V Input Threshold Voltage (Note 2)V TH2Max Duty Cycle- 3.2 3.6V SOFT-START SECTIONSoft Start Current I SOFT V SD = 0V, V SS = 0V255180µA Soft Start Low Level Voltage V SL V SD = 25V-0.30.7V Shutdown Threshold Voltage V TH(SD)-0.60.81V Shutdown Input Current I N(SD)V SD = 2.5V-0.31mA OUTPUT SECTIONLow Output Voltage I V OL I I SINK = 20mA-0.10.4V Low Output Voltage II V OL II I SINK = 100mA-0.052V High Output Voltage I V CH I I SOURCE = 20mA1819-V High Output Voltage II V CH II I SOURCE = 100mA1718-V Under Voltage Lockout V UV V8 and V9=High678V Collector Leakage Current I LKG V CC = 35V-80200µA Rise Time (Note 1)t R C L = 1uF, T J = 25°C-80600ns Fall Time (Note 1)t F C L = 1uF, T J = 25°C-70300ns STANDBY CURRENTSupply Current I CC V CC = 35V-1220mANotes :1.These parameters. although guaranteed over the recommended operating conditions, are not 100% tested in production2.Tested at f OSC=40 KHz (R T =3.6K, C T =0.01uF, R I = 0Ω)3UC3525A4Test CircuitUC3525A Mechanical DimensionsPackage16-DIP5UC3525AOrdering InformationProduct Number Package Operating Temperature UC3525AN16-DIP-30 ~ +85°C6UC3525A7UC3525A7/12/00 0.0m 001Stock#DSxxxxxxxx2000 Fairchild Semiconductor InternationalLIFE SUPPORT POLICYFAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR INTERNATIONAL. As used herein:1.Life support devices or systems are devices or systemswhich, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can bereasonably expected to result in a significant injury of the user.2. A critical component in any component of a life supportdevice or system whose failure to perform can bereasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.。

3525z中文使用资料

SG3525中文资料引脚图应用电路图(1)随着电能变换技术的发展，功率MOSFET在开关变换器中开始广泛使用。

为此，美国硅通用半导体公司推出了SG3525，以用于驱动N沟道功率MOSFET。

SG3525是一种性能优良、功能齐全和通用性强的单片集成PWM控制芯片，它简单可靠及使用方便灵活，输出驱动为推拉输出形式，增加了驱动能力；内部含有欠压锁定电路、软启动控制电路、PWM锁存器，有过流保护功能，频率可调，同时能限制最大占空比。

其性能特点如下：1) 工作电压范围宽： 8～35V。

2) 内置5．1 V±1．0％的基准电压源。

3) 芯片内振荡器工作频率宽100Hz～400 kHz。

4) 具有振荡器外部同步功能。

5) 死区时间可调。

为了适应驱动快速场效应管的需要，末级采用推拉式工作电路，使开关速度更陕，末级输出或吸入电流最大值可达400mA6) 内设欠压锁定电路。

当输入电压小于8V时芯片内部锁定，停止工作(基准源及必要电路除外)，使消耗电流降至小于2mA。

7) 有软启动电路。

比较器的反相输入端即软启动控制端芯片的引脚8，可外接软启动电容。

该电容器内部的基准电压Uref由恒流源供电，达到2．5V的时间为t=(2．5V／50μA)C，占空比由小到大(50％)变化。

8) 内置PWM(脉宽调制)。

锁存器将比较器送来的所有的跳动和振荡信号消除。

只有在下一个时钟周期才能重新置位，系统的可靠性高。

l 脉宽调制器SG3525简介1．1 结构框图SG3525是定频PWM电路，采用原理16引脚标准DIP封装。

其各引脚功能如图1所示，内部原理框图如图2所示。

1．2 引脚功能说明直流电源Vs从脚15接入后分两路，一路加到或非门；另一路送到基准电压稳压器的输入端，产生稳定的元器件作为电源。

振荡器脚5须外接电容CT，脚6须外接电阻RT。

振荡器频率厂由外接电阻RT和电容CT决定，振荡器的输出分为两路，一路以时钟脉冲形式送至双稳态触发器及两个或非门；另一路以锯齿波形式送至比较器的同相输入端，比较器的反向输入端接误差放大器的输出，误差放大器的输出与锯齿波电压在比较器中进行比较，输出一个随误差放大器输出电压高低而改变宽度的方波脉冲，再将此方波脉冲送到或非门的一个输入端。

3525（SG3525，KA3525）逆变推动板电路图

3525（SG3525，KA3525）逆变推动板电路图3525（SG3525，KA3525）逆变推动板电路图原理图：电路板设计图：电路设计图，能清楚的看清元件的位置与标号。

3525 逆变驱动板主要功能：1、应用电压范围宽(10V-22V，推荐12V)；2、电源接反保护；3、缓启动，减少启动时，瞬间电流对功率管的冲击。

本款电路默认为打渔器推动，延迟0.1-0.3秒启动，不影响使用。

做逆变器可调整为2-3秒；4、采用光耦取样，后级过流(短路)保护：后级过流(短路)保护后，延时（0.5-2秒）自动启动；5、频率18-20KHZ，R10可以调整频率(15KHZ至25KHZ)，推荐18-20KHZ；6、功率图腾管（S8050，S8550）；7、PCB采用FR4-1.5MM板材，35个铜厚；8、可以使用SG3525或KA3525芯片;9、电阻采用金属膜电阻(误差小,性能更稳定)。

10、有4种输出方式可供选择：a、集成电路直接输出，b、集成电路通过阻容耦合输出，c、功率图腾管直接输出，d、功率图腾管通过阻容耦合输出。

直接输出、阻容耦合输出，各有优缺点，直接输出：推动速度快，逆变功率管温度低，但功率管击穿后，前级必定烧坏；阻容耦合输出：对推动速度有影响，逆变功率管温度较前者高，不过，不影响使用，功率管击穿后，前级很少烧坏，维修方便。

用R3，R12时，集成电路输出；用R4，R6时，功率图腾管输出，不能同时使用哦。

本款电路使用多年，工作很稳定，保护灵敏，可靠性高。

使用方法很多：电路可以简单使用，也可以复杂使用；电流过流保护，根据不同功率、电压所需要的电流，调整取样电路的电阻R15，保护启动电流是额定电流的一倍左右为宜，仅此推荐，值得一试。

电路板照片：集成电路直接输出与集成电路通过阻容耦合输出安装照片：功率图腾管直接输出与功率图腾管通过阻容耦合输出安装照片：原理图可以复制到Word文件上，根据需要改变大小后，再打印即可。

UC3525用于光电测量系统的反馈控制

UC3525用于光电测量系统的反馈控制
乐开端;王创社;赵宏;谭玉山
【期刊名称】《半导体光电》
【年(卷),期】1998(19)6
【摘要】首次将脉宽调制控制芯片（ＵＣ３５２５）用于激光扫描测量系统，解决了激光扫描测量中因不同材料对激光的散射光强不同、不同曲面对激光光强反射各异以及物体表面镜面反射等问题给测量精度带来的严重影响［１］，利用激光扫描系统中的摄像机直接作为光强反馈系统，实现了测量过程中的光强自动控制，有效地降低了光强饱和等问题给测量带来的误差。

【总页数】3页(P383-385)
【关键词】脉宽调制器;激光线扫描测量;三角法
【作者】乐开端;王创社;赵宏;谭玉山
【作者单位】西安交通大学
【正文语种】中文
【中图分类】TN249;TN787.207
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2.一种用于红外光电系统的新型压电陶瓷扫描镜的反馈控制 [J], 赵灿兵;周春芬;胡志斌;刘鹏;王杰;陈大乾
3.用于测量印刷机套印误差的光电检测系统 [J], 孙园园;陈长缨;刘小冲;杨宇峰;肖
勇盛
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uc3525工作原理

对不起，无法提供UC3525的具体工作原理，因为这需要深入的硬件和电子技术知识。

UC3525是用于驱动LED的IC之一。

不过，通常，LED驱动IC的工作原理如下：
1. IC负责给一路或者多路LED提供稳定电压，并限制LED电流。

其内部有给LED恒流的控制电路，且采用肖特基二极管来实现两个输出电源点间的电隔离。

驱动IC的中心电压被高精度基准电源恒定，而输出则通过两个芯片内部提供的开关电源实现。

通过PWM控制芯片驱动LED的电流和亮度，输出PWM脉冲控制芯片(MOS管)可以通过改变导通程度控制LED 正向电流。

电流在LED串中的内阻基本不变。

LED的光效也相对稳定，亮度的一致性也较好。

2. UC3525是一种具有集成补偿式恒流驱动电路及控制电路的大功率LED恒流驱动IC。

它内部包含基准电源、误差检测电路、最大电流限制电路、PWM（脉冲宽度调制）控制电路以及MOS开关管等。

对于UC3525的应用，一般需要接一个电容到地以滤除高频噪声。

然后通过外接滤波电容（一般为1000uF以上）和调整限流电阻（取阻值范围在1-2欧姆之间），就可以实现给LED供电。

如果需要更详细的信息，可能需要查阅专门的电子技术资料或联系相关硬件供应商。

3525中文总结

3525总结nan’sirSG3525电压调节芯片SG3525具体的内部结构如图1所示。

其中，脚16为SG3525的基准电压源输出，精度可以达到（5.1±1％）V，采用了温度补偿，而且设有过流保护电路。

脚5，脚6，脚7内有一个双门限比较器，内电容充放电电路，加上外接的电阻电容电路共同构成SG3525的振荡器。

振荡器还设有外同步输入端(脚3)。

脚1及脚2分别为芯片内误差放大器的反相输入端、同相输入端。

该放大器是一个两级差分放大器，直流开环增益为70dB左右。

根据系统的动态、静态特性要求，在误差放大器的输出脚9和脚1之间一般要添加适当的反馈补偿网络。

图1 3525内部引脚和框图1. 下面分别阐述其各部分功能：a 基准电压源: 基准电压源是一个三端稳压电路，其输入电压V CC 可在（8～35）V 内变化，通常采用+15V ，其输出电压V ST ＝5.1V ，精度%1±，采用温度补偿，作为芯片内部电路的电源，也可为芯片外围电路提供标准电源，向外输出电流可达400mA ，没有过流保护电路。

b 振荡电路：由一个双门限电压均从基准电源取得，其高门限电压V V H 9.3=低门限电压V V L 9.0=,内部横流源向C T 充电，其端压V C 线性上升，构成锯齿波的上升沿，当H C V V =时比较器动作，充电过程结束，上升时间t 1为：T T C R t 67.01=比较器动作时使放电电路接通，C T 放电，V C 下降并形成锯齿波的下降沿，当L C V V =时比较器动作，放电过程结束，完成一个工作循环，下降时间间t 2为：T D C R t 3.12=注意：此时间即为死区时间锯齿波的基本周期T 为:()T D T C R R t t T 3.167.021+=+=因为T D R R <<⇒12t t <<由上可见锯齿波的上升沿远长于下降沿，因此上升沿作为工作沿，下降沿作为回扫沿。