Fujitsu MB3878 manual Block Diagram

Page 4

MB3878

■BLOCK DIAGRAM

−INE1 8
OUTC1 10	<Current Amp.1>	<Error	VREF
+INC1 13	+	Amp.1>	VREF
	⋅ 25	−
−INC1 12	−	+					21 VCC (O)
		+

+INE1 9				<PWM Comp.>
FB1 7				+	<OUT>
				+
				+
				+		Drive	20 OUT
−INE2 4				−		Drive	20 OUT
−INE2 4
OUTC2 2	<Current Amp.2>	<Error			VCC
	<Current Amp.2>	<Error	VREF
+INC2 24	+	Amp.2>	VREF
+INC2 24	+	−
	⋅ 25	−					19 VH
−INC2 1	−	+			Bias		19 VH
		+			Voltage	(VCC − 5 V)
+INE2 3					<VH>
FB2 5
						2.5 V
						1.5 V

		<UVLO>		VCC
	<Error			VCC
	<Error	VREF
	Amp.3>	VREF
−INE3 16	−	(VCC UVLO)215 kΩ
−INE3 16	−	+
	+	+
	+
OUTD 11	+	−	35 kΩ
			35 kΩ

	4.2 V
	4.2 V	0.91 V
		(0.77 V)
FB3 15		VREF
<SOFT>		UVLO
VREF		UVLO
VREF	∝A
1	∝A
		VCC

CS 22	bias		18	VCC
CS 22			18	VCC
<OSC>	<REF>	<CTL>	14	CTL
(45 pF)	VREF
17	6 5.0 V	23
RT	VREF	GND

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Image 4

Contents Description FeaturesPackage PIN Assignment TOP ViewPin No Symbol Descriptions PIN DescriptionBlock Diagram Parameter Symbol Conditions Rating Unit Min Max Absolute Maximum RagingsRecommended Operating Conditions ParameterElectrical Characteristics Parameter Symbol Pin Conditions Value Unit Min TypParameter Symbol Pin Conditions Value Unit Min Typ Max Outd = 1 mA 100 On resistor200 Amplifier block Output source Typical Characteristics Triangular wave oscillator Deg Functional Description PWM comparator block PWM Comp Output block OUTControl block CTL Bias voltage block VHSetting the Charging Voltage Method of Setting the Charging CurrentMethod of Setting the SOFT-START Time Method of Setting the Triangular Wave Oscillator FrequencyOperation Timing Diagram AC Adaptor Voltage DetectionProcessing Without USE of the CS PIN Vcco OUT VIN BattApplication Example OUTC2Parts No Reference Data BattVCC Vishay Siliconix Usage Precautions Ordering InformationPart number Package Remarks MB3878PFVPackage Dimension IndexFujitsu Limited