TL494中英互译

T L494应用原理(精华版)TL494常应用于电源电路当中,在本站的文章中,除了本文TL494中文资料及应用电路,还有一个电路是应用了TL494资料的,具体的电路图,请参考本站文章:200W的ATX电源线路图,本文已经提供了比较丰富的TL494中文资料了TL494是一种固定频率脉宽调制电路，它包含了开关电源控制所需的全部功能，广泛应用于单端正激双管式、半桥式、全桥式开关电源。

TL494有SO-16和PDIP-16两种封装形式，以适应不同场合的要求。

其主要特性如下：TL494主要特征集成了全部的脉宽调制电路。

片内置线性锯齿波振荡器，外置振荡元件仅两个（一个电阻和一个电容）。

内置误差放大器。

内止5V参考基准电压源。

可调整死区时间。

内置功率晶体管可提供500mA的驱动能力。

推或拉两种输出方式。

TL494外形图TL494引脚图TL494工作原理简述TL494是一个固定频率的脉冲宽度调制电路，内置了线性锯齿波振荡器，振荡频率可通过外部的一个电阻和一个电容进行调节，其振荡频率如下：输出脉冲的宽度是通过电容CT上的正极性锯齿波电压与另外两个控制信号进行比较来实现。

功率输出管Q1和Q2受控于或非门。

当双稳触发器的时钟信号为低电平时才会被选通，即只有在锯齿波电压大于控制信号期间才会被选通。

当控制信号增大，输出脉冲的宽度将减小。

参见图2。

TL494脉冲控制波形图控制信号由集成电路外部输入，一路送至死区时间比较器，一路送往误差放大器的输入端。

死区时间比较器具有120mV的输入补偿电压，它限制了最小输出死区时间约等于锯齿波周期的4%，当输出端接地，最大输出占空比为96%，而输出端接参考电平时，占空比为48%。

当把死区时间控制输入端接上固定的电压（范围在0—3.3V之间）即能在输出脉冲上产生附加的死区时间。

脉冲宽度调制比较器为误差放大器调节输出脉宽提供了一个手段：当反馈电压从0.5V变化到3.5时，输出的脉冲宽度从被死区确定的最大导通百分比时间中下降到零。

tl494引脚功能TL494是一种常用的PWM控制集成电路，具有多种功能，是广泛应用于开关电源控制电路中的一款芯片。

TL494芯片引脚的功能可以分为电源引脚、控制引脚、输出引脚和反馈引脚四大类。

首先是电源引脚，该芯片共有9个电源引脚，分别是VCC、VREF、VC、VEE、VFB、VSENSE、VOUT、RT、CT。

其中，VCC是芯片的电源引脚，用于提供TL494的工作电压；VREF 是一个内部参考电压的来源；VC是来自电源的电压，用于给内部电路提供参考电压；VEE是负电源引脚，用于提供负电源电压；VFB和VSENSE分别是反馈电压和电流感应电压的引脚，用于控制输出电压和电流；VOUT是PWM输出引脚，输出PWM信号；RT和CT是内部振荡电路的引脚，通过改变RT和CT的值，可以调整PWM信号的频率。

其次是控制引脚，该芯片共有两个控制引脚，分别是COMP和FB。

COMP是PWM比较器的输入引脚，是TL494的核心控制引脚之一，用于比较输入信号与反馈信号，控制PWM信号的占空比；FB是反馈隔离引脚，用于与比较器输入信号进行反馈，实现闭环控制。

然后是输出引脚，该芯片有三个输出引脚，分别是OUT1、OUT2和OUT3。

这三个引脚可用于输出PWM信号，OUT1和OUT2是对称的输出，用于驱动同步整流电路和同步MOS 管，OUT3是非对称输出，用于驱动静态关断开关。

最后是反馈引脚，该芯片有两个反馈引脚，分别是FB1和FB2。

FB1和FB2用于实现电流折返和过流保护，当输出过流时，这两个引脚会通过比较器将信号反馈给PWM，控制输出电流。

综上所述，TL494芯片引脚具有丰富的功能，通过控制引脚、输出引脚和反馈引脚可以实现对PWM信号频率、占空比、输出电流等的精确控制，从而实现开关电源的稳定工作。

在电源控制领域有着广泛的应用。

Designing Switching Voltage Regulators With the TL494101001 k10 k100 kf − Frequency − Hz1 µF0.1 µF0.01 µF0.001 µF−1%1%−2%−3%−4%The percent of oscillator frequency variation over the 0°C to 70°C free-air temperature range is represented by dashed lines.Figure 6.Oscillator Frequency vs R T /C TAt an operation frequency of 150 kHz, the period of the oscillator is 6.67 µestablished by the internal offset of the dead-time comparator (~3% period) yields a blanking pulse of 200 ns. This is the minimum blanking pulse acceptable to ensure proper switching of the pulse-steering flip-flop. For frequencies above 150 kHz, additional dead time (above 3%) is provided internally to ensure proper triggering and blanking of the internal pulse-steeringflip-flop. Figure 7 shows the relationship of internal dead time (expressed in percent) for various 101001 k10 k100 kf − Frequency − Hz1 µF0.1 µF 0.01 µF0.001 µF3%4%5%6%Figure 7.Variation of Dead Time vs R T /C TIMPORTANT 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. T esting 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. T o minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards.TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI.Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation.Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions:Products ApplicationsAmplifiers Audio /audioData Converters Automotive /automotiveDSP Broadband /broadbandInterface Digital Control /digitalcontrolLogic Military /militaryPower Mgmt Optical Networking /opticalnetwork Microcontrollers Security /securityTelephony /telephonyVideo & Imaging /videoWireless /wirelessMailing Address:Texas InstrumentsPost Office Box 655303 Dallas, Texas 75265Copyright 2005, Texas Instruments Incorporated。

现货库存、技术资料、百科信息、热点资讯，精彩尽在鼎好!TL494, NCV494SWITCHMODE ™ Pulse Width Modulation Control CircuitThe TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control.Features•Complete Pulse Width Modulation Control Circuitry •On−Chip Oscillator with Master or Slave Operation •On−Chip Error Amplifiers •On−Chip 5.0 V Reference •Adjustable Deadtime Control•Uncommitted Output Transistors Rated to 500 mA Source or Sink •Output Control for Push−Pull or Single−Ended Operation •Undervoltage Lockout•NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes•Pb−Free Packages are Available*MAXIMUM RATINGS (Full operating ambient temperature range applies,unless otherwise noted.)RatingSymbol Value UnitPower Supply Voltage V CC 42V Collector Output Voltage V C1,V C242V Collector Output Current (Each transistor) (Note 1)I C1, I C2500mA Amplifier Input Voltage Range V IR −0.3 to +42V Power Dissipation @ T A ≤ 45°CP D 1000mW Thermal Resistance, Junction−to−Ambient R q JA 80°C/W Operating Junction Temperature T J 125°C Storage Temperature RangeT stg −55 to +125°C Operating Ambient Temperature Range TL494B TL494C TL494I NCV494BT A−40 to +1250 to +70−40 to +85−40 to +125°CDerating Ambient TemperatureT A45°C Maximum ratings are those values beyond which device damage can occur.Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected.1.Maximum thermal limits must be observed.*For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D.MARKING DIAGRAMSSOIC−16D SUFFIX CASE 751BSee detailed ordering and shipping information in the package dimensions section on page 4 of this data sheet.ORDERING INFORMATIONTL494xDG AWLYWW x = B, C or IA = Assembly Location WL = Wafer Lot YY , Y = YearWW, W = Work WeekG= Pb−Free Package116PDIP−16N SUFFIX CASE 648*This marking diagram also applies to NCV494.PIN CONNECTIONSC T R T Ground C1Inv Input C2E2E1Noninv Input Inv Input V ref Output Control V CC Noninv Input Compen/PWN Comp Input Deadtime Control TL494xN AWLYYWWG*116RECOMMENDED OPERATING CONDITIONSCharacteristics Symbol Min Typ Max Unit Power Supply Voltage V CC7.01540V Collector Output Voltage V C1, V C2−3040V Collector Output Current (Each transistor)I C1, I C2−−200mA Amplified Input Voltage V in−0.3−V CC − 2.0V Current Into Feedback Terminal l fb−−0.3mA Reference Output Current l ref−−10mA Timing Resistor R T 1.830500k W Timing Capacitor C T0.00470.00110m F Oscillator Frequency f osc 1.040200kHzELECTRICAL CHARACTERISTICS (V CC = 15 V, C T = 0.01 m F, R T = 12 k W, unless otherwise noted.)For typical values T A = 25°C, for min/max values T A is the operating ambient temperature range that applies, unless otherwise noted.Characteristics Symbol Min Typ Max Unit REFERENCE SECTIONReference Voltage (I O = 1.0 mA)V ref 4.75 5.0 5.25V Line Regulation (V CC = 7.0 V to 40 V)Reg line− 2.025mV Load Regulation (I O = 1.0 mA to 10 mA)Reg load− 3.015mV Short Circuit Output Current (V ref = 0 V)I SC153575mA OUTPUT SECTIONCollector Off−State Current(V CC = 40 V, V CE = 40 V)I C(off)− 2.0100m AEmitter Off−State CurrentV CC = 40 V, V C = 40 V, V E = 0 V)I E(off)−−−100m A Collector−Emitter Saturation Voltage (Note 2)Common−Emitter (V E = 0 V, I C = 200 mA) Emitter−Follower (V C = 15 V, I E = −200 mA)V sat(C)V sat(E)−−1.11.51.32.5VOutput Control Pin CurrentLow State (V OC v 0.4 V) High State (V OC = V ref)I OCLI OCH−−100.2−3.5m AmAOutput Voltage Rise Time Common−Emitter (See Figure 12) Emitter−Follower (See Figure 13)t r−−100100200200nsOutput Voltage Fall TimeCommon−Emitter (See Figure 12) Emitter−Follower (See Figure 13)t f−−2540100100ns2.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.ELECTRICAL CHARACTERISTICS (V CC = 15 V, C T = 0.01 m F, R T = 12 k W, unless otherwise noted.)For typical values T A = 25°C, for min/max values T A is the operating ambient temperature range that applies, unless otherwise noted.Characteristics Symbol Min Typ Max Unit ERROR AMPLIFIER SECTIONInput Offset Voltage (V O(Pin3) = 2.5 V)V IO− 2.010mV Input Offset Current (V O(Pin3) = 2.5 V)I IO− 5.0250nA Input Bias Current (V O(Pin3) = 2.5 V)I IB−−0.1−1.0m A Input Common Mode Voltage Range (V CC = 40 V, T A = 25°C)V ICR−0.3 to V CC−2.0V Open Loop Voltage Gain (D V O = 3.0 V, V O = 0.5 V to 3.5 V, R L = 2.0 k W)A VOL7095−dB Unity−Gain Crossover Frequency (V O = 0.5 V to 3.5 V, R L = 2.0 k W)f C−−350−kHz Phase Margin at Unity−Gain (V O = 0.5 V to 3.5 V, R L = 2.0 k W)f m−65−deg. Common Mode Rejection Ratio (V CC = 40 V)CMRR6590−dB Power Supply Rejection Ratio (D V CC = 33 V, V O = 2.5 V, R L = 2.0 k W)PSRR−100−dB Output Sink Current (V O(Pin3) = 0.7 V)I O−0.30.7−mA Output Source Current (V O(Pin3) = 3.5 V)I O+ 2.0−4.0−mA PWM COMPARATOR SECTION (Test Circuit Figure 11)Input Threshold Voltage (Zero Duty Cycle)V TH− 2.5 4.5V Input Sink Current (V(Pin3) = 0.7 V)I I−0.30.7−mA DEADTIME CONTROL SECTION (Test Circuit Figure 11)Input Bias Current (Pin 4) (V Pin4 = 0 V to 5.25 V)I IB(DT)−−2.0−10m AMaximum Duty Cycle, Each Output, Push−Pull Mode (V Pin4 = 0 V, C T = 0.01 m F, R T = 12 k W)(V Pin4 = 0 V, C T = 0.001 m F, R T = 30 k W)DC max45−48455050%Input Threshold Voltage (Pin 4) (Zero Duty Cycle) (Maximum Duty Cycle)V th−2.8−3.3−VOSCILLATOR SECTIONFrequency (C T = 0.001 m F, R T = 30 k W)f osc−40−kHz Standard Deviation of Frequency* (C T = 0.001 m F, R T = 30 k W)s f osc− 3.0−% Frequency Change with Voltage (V CC = 7.0 V to 40 V, T A = 25°C)D f osc (D V)−0.1−% Frequency Change with Temperature (D T A = T low to T high)(C T = 0.01 m F, R T = 12 k W)D f osc (D T)−−12%UNDERVOLTAGE LOCKOUT SECTIONTurn−On Threshold (V CC increasing, I ref = 1.0 mA)V th 5.5 6.437.0V TOTAL DEVICEStandby Supply Current (Pin 6 at V ref, All other inputs and outputs open) (V CC = 15 V)(V CC = 40 V)I CC−−5.57.01015mAAverage Supply Current(C T = 0.01 m F, R T = 12 k W, V(Pin4) = 2.0 V) (V CC = 15 V) (See Figure 12)−7.0−mA* Standard deviation is a measure of the statistical distribution about the mean as derived from the formula, sORDERING INFORMATIONDevice Package Shipping†TL494BD SOIC−1648 Units / Rail48 Units / RailTL494BDG SOIC−16(Pb−Free)TL494BDR2SOIC−162500 Tape & Reel2500 Tape & ReelTL494BDR2G SOIC−16(Pb−Free)TL494CD SOIC−1648 Units / Rail48 Units / RailTL494CDG SOIC−16(Pb−Free)TL494CDR2SOIC−162500 Tape & Reel2500 Tape & ReelTL494CDR2G SOIC−16(Pb−Free)TL494CN PDIP−1625 Units / RailTL494CNG PDIP−1625 Units / Rail(Pb−Free)TL494IN PDIP−1625 Units / Rail25 Units / RailTL494ING PDIP−16(Pb−Free)NCV494BDR2*SOIC−162500 Tape & Reel2500 Tape & ReelNCV494BDR2G*SOIC−16(Pb−Free)†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D.*NCV494: T low = −40°C, T high = +125°C. Guaranteed by design. NCV prefix is for automotive and other applications requiring site and change control.Figure 1. Representative Block DiagramFigure 2. Timing DiagramR V Capacitor C TDeadtime ControlThis device contains 46 active transistors.APPLICATIONS INFORMATIONDescriptionThe TL494 is a fixed−frequency pulse width modulation control circuit, incorporating the primary building blocks required for the control of a switching power supply. (See Figure 1.) An internal−linear sawtooth oscillator is frequency− programmable by two external components, R T and C T. The approximate oscillator frequency is determined by:f osc≈ 1.1R T• C TFor more information refer to Figure 3.Output pulse width modulation is accomplished by comparison of the positive sawtooth waveform across capacitor C T to either of two control signals. The NOR gates, which drive output transistors Q1 and Q2, are enabled only when the flip−flop clock−input line is in its low state. This happens only during that portion of time when the sawtooth voltage is greater than the control signals. Therefore, an increase in control−signal amplitude causes a corresponding linear decrease of output pulse width. (Refer to the Timing Diagram shown in Figure 2.)The control signals are external inputs that can be fed into the deadtime control, the error amplifier inputs, or the feedback input. The deadtime control comparator has an effective 120 mV input offset which limits the minimum output deadtime to approximately the first 4% of the sawtooth−cycle time. This would result in a maximum duty cycle on a given output of 96% with the output control grounded, and 48% with it connected to the reference line. Additional deadtime may be imposed on the output by setting the deadtime−control input to a fixed voltage, ranging between 0 V to 3.3 V.Functional TableThe pulse width modulator comparator provides a means for the error amplifiers to adjust the output pulse width from the maximum percent on−time, established by the deadtime control input, down to zero, as the voltage at the feedback pin varies from 0.5 V to 3.5 V. Both error amplifiers have a common mode input range from −0.3 V to (V CC − 2V), and may be used to sense power−supply output voltage and current. The error−amplifier outputs are active high and are ORed together at the noninverting input of the pulse−width modulator comparator. With this configuration, the amplifier that demands minimum output on time, dominates control of the loop.When capacitor C T is discharged, a positive pulse is generated on the output of the deadtime comparator, which clocks the pulse−steering flip−flop and inhibits the output transistors, Q1 and Q2. With the output−control connected to the reference line, the pulse−steering flip−flop directs the modulated pulses to each of the two output transistors alternately for push−pull operation. The output frequency is equal to half that of the oscillator. Output drive can also be taken from Q1 or Q2, when single−ended operation with a maximum on−time of less than 50% is required. This is desirable when the output transformer has a ringback winding with a catch diode used for snubbing. When higher output−drive currents are required for single−ended operation, Q1 and Q2 may be connected in parallel, and the output−mode pin must be tied to ground to disable the flip−flop. The output frequency will now be equal to that of the oscillator.The TL494 has an internal 5.0 V reference capable of sourcing up to 10 mA of load current for external bias circuits. The reference has an internal accuracy of $5.0% with a typical thermal drift of less than 50 mV over an operating temperature range of 0° to 70°C.Figure 3. Oscillator Frequency versusTiming Resistance1.0 k2.0 k 5.0 k10 k20 k50 k100 k200 k500 k1.0 MR T, TIMING RESISTANCE (W),OSCILLATORFREQUENCY(Hz)fosc, O P E N L O O P V O L T A G E G A I N (d B )V O L A % D C , P E R C E N T D U T Y C Y C L E (E A C H O U T P U T )Figure 8. Common−Emitter ConfigurationOutput Saturation Voltage versusCollector Current100200300400I C , COLLECTOR CURRENT (mA)C E (s a t ) , S A T U R A T I O N V O L T A G E (V )V Figure 9. Standby Supply Currentversus Supply Voltage5.010152025303540V CC , SUPPLY VOLTAGE (V)9080706050403020105040302010Figure 12. Common−Emitter Configuration Test Circuit and WaveformOutput 1Output 2 Figure 13. Emitter−Follower ConfigurationTest Circuit and WaveformFigure 14. Error−Amplifier Sensing TechniquesFigure 15. Deadtime Control Circuit Figure 16. Soft−Start CircuitFigure 17. Output Connections for Single−Ended and Push−Pull ConfigurationsV refV R2V OC SCEL1−**********T1 − Primary: 20T C.T. #28 AWG Secondary: 12OT C.T. #36 AWG Core: Ferroxcube 1408P−L00−3CBFigure 18. Slaving Two or More Control CircuitsFigure 19. Operation with V in > 40 V UsingExternal ZenerFigure 20. Pulse Width Modulated Push−Pull ConverterRV MasterSlave (Additional Circuits)V +V= 8.0V to 20VTestConditionsResultsLine Regulation V in = 10 V to 40 V14 mV 0.28%Load Regulation V in = 28 V, I O = 1.0 mA to 1.0 A 3.0 mV 0.06%Output Ripple V in = 28 V, I O = 1.0 A 65 mV pp P .A.R.D.Short Circuit Current V in = 28 V, R L = 0.1 W 1.6 A EfficiencyV in = 28 V, I O = 1.0 A71%1.0mH @ 2AFigure 21. Pulse Width Modulated Step−Down ConverterTest Conditions ResultsLine Regulation V in = 8.0 V to 40 V 3.0 mV0.01% Load Regulation V in = 12.6 V, I O = 0.2 mA to 200 mA 5.0 mV0.02% Output Ripple V in = 12.6 V, I O = 200 mA40 mV pp P.A.R.D. Short Circuit Current V in = 12.6 V, R L = 0.1 W250 mA Efficiency V in = 12.6 V, I O = 200 mA72%SOIC−16D SUFFIX CASE 751B−05ISSUE JNOTES:1.DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.2.CONTROLLING DIMENSION: MILLIMETER.3.DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION.4.MAXIMUM MOLD PROTRUSION 0.15 (0.006)PER SIDE.5.DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBARPROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION.SBM0.25 (0.010)AST DIM MIN MAX MIN MAX INCHESMILLIMETERS A 9.8010.000.3860.393B 3.80 4.000.1500.157C 1.35 1.750.0540.068D 0.350.490.0140.019F 0.40 1.250.0160.049G 1.27 BSC 0.050 BSC J 0.190.250.0080.009K 0.100.250.0040.009M 0 7 0 7 P 5.80 6.200.2290.244R0.250.500.0100.019____PDIP−16N SUFFIXCASE 648−08ISSUE TNOTES:1.DIMENSIONING AND TOLERANCING PERANSI Y14.5M, 1982.2.CONTROLLING DIMENSION: INCH.3.DIMENSION L TO CENTER OF LEADSWHEN FORMED PARALLEL.4.DIMENSION B DOES NOT INCLUDEMOLD FLASH.5.ROUNDED CORNERS OPTIONAL.M DIM MIN MAX MIN MAXMILLIMETERSINCHESA0.7400.77018.8019.55 B0.2500.270 6.35 6.85 C0.1450.175 3.69 4.44 D0.0150.0210.390.53 F0.0400.70 1.02 1.77 G0.100 BSC 2.54 BSCH0.050 BSC 1.27 BSCJ0.0080.0150.210.38 K0.1100.130 2.80 3.30 L0.2950.3057.507.74 M0 10 0 10 S0.0200.0400.51 1.01____SWITCHMODE is a trademark of Semiconductor Components Industries, LLC.ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. 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AND 与门ANTENNA 天线BATTERY 直流电源BELL 铃钟BVC 同轴电缆接插件BRIDEG 1 整流桥(二极管)BRIDEG 2 整流桥(集成块) BUFFER 缓冲器BUZZER 蜂鸣器CAP 电容CAPACITOR 电容CAPACITOR POL 有极性电容CAPVAR 可调电容CIRCUIT BREAKER 熔断丝COAX 同轴电缆CON 插口CRYSTAL 晶体整荡器DB 并行插口DIODE 二极管DIODE SCHOTTKY 稳压二极管DIODE VARACTOR 变容二极管DPY_3-SEG 3段LEDDPY_7-SEG 7段LEDDPY_7-SEG_DP 7段LED(带小数点) ELECTRO 电解电容FUSE 熔断器INDUCTOR 电感INDUCTOR IRON 带铁芯电感INDUCTOR3 可调电感JFET N-N沟道场效应管JFET P-P沟道场效应管LAMP 灯泡LAMP NEDN 起辉器LED 发光二极管METER 仪表MICROPHONE 麦克风MOSFET MOS管MOTOR AC 交流电机MOTOR SERVO 伺服电机NAND 与非门NOR 或非门NOT 非门NPN-NPN三极管NPN-PHOTO感光三极管OPAMP 运放OR 或门PHOTO 感光二极管PNP 三极管NPN DAR NPN三极管PNP DAR PNP三极管POT 滑线变阻器PELAY-DPDT 双刀双掷继电器RES1.2 电阻RES3.4 可变电阻RESISTOR BRIDGE 桥式电阻RESPACK 电阻SCR 晶闸管PLUG 插头PLUG AC FEMALE 三相交流插头SOCKET 插座SOURCE CURRENT 电流源SOURCE VOLTAGE 电压源SPEAKER 扬声器SW 开关SW-DPDY 双刀双掷开关SW-SPST 单刀单掷开关SW-PB 按钮THERMISTOR 电热调节器TRANS1 变压器TRANS2 可调变压器TRIAC 三端双向可控硅TRIODE 三极真空管VARISTOR 变阻器ZENER 齐纳二极管DPY_7-SEG_DP 数码管SW-PB 开关。

TL494的标准应用参数 - 大功率逆变器电路设计过程详解TL494的标准应用参数：Vcc(第12脚)为7～40V，Vcc1(第8脚)、Vcc2(第11脚)为40V，Ic1、Ic2为200mA，RT 取值范围1.8～500kΩ，CT取值范围4700pF～10μF，最高振荡频率(fOSC)≤300kHz图4为外刊介绍的利用TL494组成的400W大功率稳压逆变器电路。

它激式变换部分采用TL494，VT1、VT2、VD3、VD4构成灌电流驱动电路，驱动两路各两只60V/30A的MOS FET开关管。

如需提高输出功率，每路可采用3～4只开关管并联应用，电路不变。

TL494在该逆变器中的应用方法如下：图4 400W大功率稳压逆变器电路第1、2脚构成稳压取样、误差放大系统，正相输入端1脚输入逆变器次级取样绕组整流输出的15V直流电压，经R1、R2分压，使第1脚在逆变器正常工作时有近4.7～5.6V取样电压。

反相输入端2脚输入5V基准电压(由14脚输出)。

当输出电压降低时，1脚电压降低，误差放大器输出低电平，通过PWM电路使输出电压升高。

正常时1脚电压值为5.4V，2脚电压值为5V，3脚电压值为0.06V。

此时输出AC电压为235V(方波电压)。

第4脚外接R6、R4、C2设定死区时间。

正常电压值为0.01V。

第5、6脚外接CT、RT设定振荡器三角波频率为100Hz。

正常时5脚电压值为1.75V，6脚电压值为3.73V。

第7脚为共地。

第8、11脚为内部驱动输出三极管集电极，第12脚为TL494前级供电端，此三端通过开关S控制TL494的启动/停止，作为逆变器的控制开关。

当S1关断时，TL494无输出脉冲，因此开关管VT4～VT6无任何电流。

S1接通时，此三脚电压值为蓄电池的正极电压。

第9、10脚为内部驱动级三极管发射极，输出两路时序不同的正脉冲。

正常时电压值为1.8V。

第13、14、15脚其中14脚输出5V基准电压，使13脚有5V高电平，控制门电路，触发器输出两路驱动脉冲，用于推挽开关电路。

tl494逆变器工作原理TL494是一款常用的PWM控制芯片，它在逆变器中扮演着重要的角色。

逆变器是一种将直流电转换为交流电的装置，常用于太阳能发电系统、UPS系统和电动汽车等领域。

本文将介绍TL494逆变器的工作原理，希望能对您有所帮助。

首先，让我们来了解一下TL494芯片的基本结构。

TL494是一款集成了PWM控制器的芯片，它包含了错误放大器、比较器、PWM 控制电路和内部参考电压源等部分。

通过对这些功能模块的合理配置，我们可以实现对逆变器输出波形的精确控制。

在逆变器中，TL494芯片通常被用来控制MOSFET管的开关，从而调节输出波形的频率和占空比。

具体来说，当输入直流电压进入逆变器后，TL494芯片会根据输入信号的变化，通过内部的PWM控制电路生成相应的PWM信号。

这些PWM信号经过比较器的比较后，控制MOSFET管的导通和关断，从而实现对输出交流电波形的调节。

此外，TL494芯片还具有过流保护和短路保护等功能。

当逆变器工作过程中出现异常情况时，TL494芯片能够及时检测到并采取相应的保护措施，确保逆变器和相关设备的安全稳定运行。

总的来说，TL494逆变器的工作原理可以概括为，通过PWM控制器对MOSFET管进行精确的开关控制，从而实现对输出波形的调节；同时具备过流保护和短路保护等功能，确保逆变器的安全可靠运行。

在实际应用中，我们可以根据具体的需求和电路设计，合理选择TL494芯片的工作参数，并结合其他元器件构建出稳定可靠的逆变器系统。

通过对TL494逆变器工作原理的深入理解，我们能够更好地应用它在各种电力系统中，为我们的生活和工作提供更加稳定和可靠的电力支持。

希望本文对您理解TL494逆变器的工作原理有所帮助，如果您对逆变器或其他相关领域有更深入的了解和需求，欢迎继续关注我们的文档，我们将为您提供更多的专业知识和技术支持。

T L494脉宽调制控制电路TL494是一种固定频率脉宽调制电路，它主要为开关电源电路而设计。

·集成了全部的脉宽调制电路·内置主从振荡器·内置误差放大器·内置5.0V参考基准电压源·可调整死区时间·内置功率晶体管可提供最大500mA的驱动能力·输出可控制推拉电路或单端电路·欠压保护最大额定值：注意：必须注意最大发热限制。

Powersupplyvoltage:电源电压CollectorOutputVoltage:集电极输出电压CollectorOutputCurrent（Eachtransistor）：集电极输出电流（每一个管子）AmplifierInputVoltageRange：输入放大器电压范围PowerDissipation@TA<?45?C：45℃下功率损耗ThermalResistance,Junction–to–Ambien：结对环境热敏阻抗OperatingJunctionTemperature：结点工作温度StorageTemperatureRange：储存温度范围OperatingAmbientTemperatureRange：运行环境范围DeratingAmbientTemperature：降额温度推荐工作条件电特性（VCC=15V,CT=0.01uF,R T=12kW，无特殊说明下）参考区输出区误差放大区PWM比较区（图11测试电路）死区电压控制区（图11测试电路）振荡区欠压保护区整个器件*标准差是一种平均统计分布，从右公式得来：图1.典型代表方框图此器件包含46个有效晶体管图2.时序图应用资料TL494是一个固定频率的脉冲宽度调制电路，内置线性锯齿波振荡器，振荡频率可通过外部的电阻R T和电容C T来进行调节，其振荡频率为：输出脉冲的宽度是通过电容C T上的正极性锯齿波电压与另外两个控制信号进行比较来实现。