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Fujitsu MB39A104 manual L priority, CH ON/OFF signal, L On, H Off, Soft-Start Circuit

Models: MB39A104

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			MB39A104
• Soft-Start Circuit
VO			VREF
VO
R1			10 ∝A
	−INE1	10
		10
	(−INE2)	15
		15
R2			L priority
			L priority
			Error Amp
			−
CH ON/OFF signal		11	+
L : ON, H : OFF		11	+
L : ON, H : OFF	CS1		+
	CS1	14
	(CS2)	14	1.24 V
	CS1		1.24 V
	(CS2)
	FB1	9
	(FB2)	16	UVLO

Page 15

Image 15

Fujitsu MB39A104 manual L priority, CH ON/OFF signal, L On, H Off, Soft-Start Circuit

Contents

PACKAGE FEATURESFUJITSU SEMICONDUCTOR DATA SHEET DESCRIPTIONPIN ASSIGNMENTS MB39A104Pin No PIN DESCRIPTIONSymbol MB39A1041.24 BLOCK DIAGRAMMB39A104 biasSymbol ABSOLUTE MAXIMUM RATINGSRECOMMENDED OPERATING CONDITIONS SymbolPin No ELECTRICAL CHARACTERISTICSMB39A104 ParameterParameter SymbolMB39A104 ContinuedVREFV TYPICAL CHARACTERISTICSMB39A104 ICCmAContinued Triangular Wave Oscillation Frequency vs. Ambient TemperatureMB39A104 vs. Timing ResistorContinued Error Amplifier, Gain, Phase vs. FrequencyPower Dissipation vs. Ambient Temperature MB39A104MB39A104 FUNCTIONS1. DC/DC Converter Functions 3 Error amplifier block Error Amp1, Error Amp22 Timer-latch short-circuit protection circuit SCP Logic, SCP Comp 2. Control Function3. Protective Functions 1 Timer-latch overcurrent protection circuit block OCPSETTING THE OUTPUT VOLTAGE SETTING THE TRIANGULAR OSCILLATION FREQUENCYMB39A104 MB39A104 SETTING THE SOFT-START AND DISCHARGE TIMESL ON, H OFF CH ON/OFF signalMB39A104 L priorityTREATMENT WITHOUT USING CS TERMINAL Without Setting Soft-Start TimeMB39A104 ABOUT TIMER-LATCH PROTECTION CIRCUIT 1. Setting Timer-Latch Overcurrent Protection Detection CurrentMB39A104 Overcurrent Protection Circuit Range of Operation Method to detect by current when external FETQ1 is turned onMB39A104 Overcurrent Detection Function Operating RangeMB39A104 Timer-latch short-circuit protection circuitMB39A104 TREATMENT WITHOUT USING CSCP TERMINALRESETTING THE LATCH OF EACH PROTECTION CIRCUIT Treatment without using CSCPMB39A104 I/O EQUIVALENT CIRCUITV TH = 1.4 H ON Power ONL OFF Standby mode MB39A104MB39A104 PARTS LISTSELECTION OF COMPONENTS MB39A104Pch MOS FET MB39A104 Inductors MB39A104IO ≥ MB39A104MB39A104 Flyback diode MB39A104MB39A104 Smoothing Capacitor2 π ⋅ 500 ⋅ 10 3 ⋅ 82 ⋅ 10 − 2 π ⋅ 500 ⋅ 10 3 ⋅ 0.033 − 0.364 ⋅ MB39A104⋅ 10 2 π ⋅ 500 ⋅ 10 3 ⋅ 0.050 − 0.491 ⋅10 m REFERENCE DATAMB39A104 ContinuedContinued Switching Wave Form CH1Switching Wave Form CH2 MB39A104Take appropriate static electricity measures USAGE PRECAUTIONORDERING INFORMATION MB39A104MB39A104 PACKAGE DIMENSIONSFUJITSU LIMITED MB39A104F0308  FUJITSU LIMITED Printed in Japan

MB39A104

• Soft-Start Circuit

L priority

CH ON/OFF signal

L : ON, H : OFF