Fujitsu MB39A104 manual Equivalent Circuit

Page 21

MB39A104

■I/O EQUIVALENT CIRCUIT

〈〈Reference voltage block〉〉

〈〈Control block〉〉

〈〈Soft-start block〉〉

VCC 7

GND 18

1.24 V	+
	−
	77.8
	kΩ
	24.8
	kΩ

CTL 24

17VREF

GND

72 kΩ

104 kΩ

VREF	VCC
(5.0 V)
	CSX
GND

〈〈Short-circuit detection block〉〉

VREF
(5.0 V)
2 kΩ	CSCP
8	CSCP
GND

〈〈Triangular wave oscillator			〈〈Triangular wave oscillator
	block (RT) 〉〉	VCC	(CT) block〉〉
(3.1 V)			(3.1 V)
(3.1 V)
1.35 V	+		CT 13
	−		CT 13
	−
		12 RT
GND			GND

〈〈Error amplifier block (CH1, CH2) 〉〉

〈〈Overcurrent protection circuit block〉〉

VCC
VREF
(5.0 V)
−INEX	CSX
	1.24 V	FBX
GND
〈〈PWM comparator		〈〈Bias voltage block〉〉
block (CH1, CH2) 〉〉		〈〈Bias voltage block〉〉

VCC	VCCO
VCC
ILIMX	VSX
GND	GNDO
	GNDO
	〈〈Output block (CH1, CH2) 〉〉

VCC

FBX

DTCX

GND

VCC	VCCO
CT
2	VH
GND	GNDO

VCCO	1
VH
GNDO 23

X : Each channel No.

21

Image 21

Contents Features DescriptionPackage PIN Assignments MB39A104PIN Description Pin No Symbol DescriptionsBlock Diagram Parameter Symbol Condition Value Unit Min Typ Parameter Symbol Condition Rating Unit Min MaxAbsolute Maximum Ratings Recommended Operating ConditionsParameter Electrical CharacteristicsPin No Conditions Min Typ MaxPin No Conditions Value Unit Min Parameter SymbolReference Voltage vs. Ambient Temperature Typical CharacteristicsTriangular Wave Oscillation Frequency Power Dissipation vs. Ambient Temperature Functions Under voltage lockout protection circuit Uvlo Timer-latch overcurrent protection circuit block OCPProtection circuit operating function table Operating circuitSetting the Triangular Oscillation Frequency Setting the Output VoltageSetting the SOFT-START and Discharge Times MB39A104 Without Setting Soft-Start Time Treatment Without Using CS TerminalOvercurrent detection circuit About TIMER-LATCH Protection CircuitMethod to detect by mean current Overcurrent Protection Circuit Range of OperationTimer-latch short-circuit protection circuit Resetting the Latch of Each Protection Circuit Treatment Without Using Cscp TerminalEquivalent Circuit On Power on OFF Standby mode Component Specification Vendor Parts ListCH1 Selection of ComponentsCH2 = 3 2 ⋅ 0.05 ⋅ 0.174 = 0.078 W Example Peak-to-peak value ΔIL Di ≥ I O ⋅ 1 − ESR ≤ ΠfC L 050 491 ESR ≤ ΠfC L 033 364 Total Efficiency vs. Input Voltage Reference DataSwitching Wave Form CH1 Ordering Information Usage PrecautionDo not apply negative voltages Part number Package RemarksIndex Package DimensionsFujitsu Limited