Simplicity 1692543 Manuel d'utilisateur

LT395713957fn Wide Input Voltage Range: 3V to 40V n Single Feedback Pin for Positive or Negative Output Voltage n Internal 5A/40V Power Switchn Cu

LT3957103957f APPLICATIONS INFORMATIONINTVCC Regulator Bypassing and OperationAn internal, low dropout (LDO) voltage regulator produces the 5.2V INTVC

LT3957113957f APPLICATIONS INFORMATIONOperating Frequency and SynchronizationThe choice of operating frequency may be determined by on-chip power diss

LT3957123957f APPLICATIONS INFORMATIONSoft-Start The LT3957 contains several features to limit peak switch currents and output voltage (VOUT) overshoo

LT3957133957f APPLICATIONS INFORMATIONThe Internal Power Switch CurrentFor control and protection, the LT3957 measures the internal power MOSFET curre

LT3957143957f APPLICATIONS INFORMATIONAPPLICATION CIRCUITSThe LT3957 can be confi gured as different topologies. The fi rst topology to be analyzed will

LT3957153957f APPLICATIONS INFORMATIONThe power dissipated by the diode is: PD = IO(MAX) • VDwhere VD is diode’s forward voltage drop, and the diode j

LT3957163957f APPLICATIONS INFORMATIONFigure 7 shows the waveforms of the fl yback converter in discontinuous mode operation. During each switching per

LT3957173957f APPLICATIONS INFORMATIONAccording to the Absolute Maximum Ratings table, the SW voltage Absolute Maximum value is 40V. Therefore, the ma

LT3957183957f APPLICATIONS INFORMATIONIn some cases a snubber circuit will be required to avoid overvoltage breakdown at the MOSFET’s drain node. Ther

LT3957193957f APPLICATIONS INFORMATIONSEPIC CONVERTER APPLICATIONSThe LT3957 can be confi gured as a SEPIC (single-ended primary inductance converter),

LT395723957f PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGSVIN, EN/UVLO (Note 5), SW ...40V INTVCC ...

LT3957203957f APPLICATIONS INFORMATIONBy making L1 = L2, and winding them on the same core, the value of inductance in the preceding equation is repla

LT3957213957f APPLICATIONS INFORMATIONInverting Converter: Switch Duty Cycle and FrequencyFor an inverting converter operating in CCM, the duty cycle

LT3957223957f APPLICATIONS INFORMATION• In fl yback confi guration, the high di/dt primary loop contains the input capacitor, the primary winding, the

LT3957233957f APPLICATIONS INFORMATIONTable 2. Recommended Component ManufacturersVENDOR COMPONENTS WEB ADDRESSAVX Capacitors avx.comBH Electronics In

LT3957243957f TYPICAL APPLICATIONS4.5V to 16V Input, 24V Output Boost ConverterEffi ciency vs Output CurrentSENSE2SENSE1LT3957L110µHVINSWGNDFBXRT SSINT

LT3957253957f TYPICAL APPLICATIONS5V to 16V Input, 12V Output SEPIC ConverterEffi ciency vs Output CurrentLoad Step WaveformsStart-Up WaveformsFrequenc

LT3957263957f TYPICAL APPLICATIONS5V to 16V Input, –12V Output Inverting ConverterEffi ciency vs Output CurrentLoad Step WaveformsStart-Up WaveformsFre

LT3957273957fInformation furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for

LT3957283957fLinear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com© LINEA

LT395733957f ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temp-erature range, otherwise specifi cati

LT395743957f ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temp-erature range, otherwise specifi cati

LT395753957fTYPICAL PERFORMANCE CHARACTERISTICSTA ≈ TJ = 25°C, unless otherwise noted.Dynamic Quiescent Current vs Switching FrequencyRT vs Switching

LT395763957fINTVCC Line RegulationINTVCC Dropout Voltage vs Current, TemperatureINTVCC vs TemperatureINTVCC Minimum Output Current Limit vs VININTVCC

LT395773957f PIN FUNCTIONSNC (Pins 1, 2, 10, 35, 36): No Internal Connection. Leave these pins open or connect them to the adjacent pins.SENSE2 (Pin 3

LT395783957f BLOCK DIAGRAMFigure 1. LT3957 Block Diagram Working as a SEPIC ConverterL1R3R4L21.22V2.5VD1CDCCINVOUTCOUTCVCCINTVCCSENSE1GNDSENSE2M2VINRS

LT395793957f APPLICATIONS INFORMATIONMain Control LoopThe LT3957 uses a fi xed frequency, current mode control scheme to provide excellent line and loa