Fujitsu MB3878 - Manual - manualsarea.com

Page 2 - PIN ASSIGNMENT

MB3878 2 (Continued) • Built-in current detector amplifier with wide in-phase input voltage range : 0 V to Vcc• In standby mode, leave output voltage setting resistor open to prevent inefficient current loss• Built-in standby current function : 0 µ A (standard) • Built-in soft-start function• Built-...

Page 3 - PIN DESCRIPTION; Symbol

MB3878 3 ■ ■ ■ ■ PIN DESCRIPTION Pin No. Symbol I/O Descriptions 1 − INC2 I Current detection amplifier (Current Amp. 2) input pin. 2 OUTC2 O Current detection amplifier (Current Amp. 2) output pin. 3 + INE2 I Error amplifier (Error Amp. 2) non-inverted input pin. 4 − INE2 I Error amplifier (Error A...

Page 4 - BLOCK DIAGRAM

MB3878 4 ■ ■ ■ ■ BLOCK DIAGRAM + − − + 8 10 13 12 9 + − − + 4 2 24 1 3 × 25 × 25 + + + − 5 20 21 19 − + + + − 11 16 22 17 6 23 14 18 <Current Amp.1> <Error Amp.1> 7 VREF <Current Amp.2> <Error Amp.2> VREF <Error Amp.3> VREF VREF VREF5.0 V 4.2 V 1 µ A 15 <SOFT> 2.5...

Page 6 - ELECTRICAL CHARACTERISTICS

MB3878 6 ■ ■ ■ ■ ELECTRICAL CHARACTERISTICS (Ta = + 25 ° C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) * : Standard design value. (Continued) Parameter Symbol Pin No. Conditions Value Unit Min Typ Max Reference voltage block (Ref) Output voltage V REF 6 Ta = + 25 ° C 4.995 5.000 5.045 V Ta = − 30 ° C ...

Page 7 - Output sink current

MB3878 7 (Ta = + 25 ° C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) * : Standard design value. (Continued) Parameter Symbol Pin No. Conditions Value Unit Min Typ Max Error amplifier block(Error Amp.3) Threshold voltage V TH1 16 FB3 = 2 V, Ta = + 25 ° C 4.167 4.200 4.233 V V TH2 16 FB3 = 2 V, Ta = − 30...

Page 9 - TYPICAL CHARACTERISTICS

MB3878 9 ■ ■ ■ ■ TYPICAL CHARACTERISTICS (Continued) Ta = + 25 ° C CTL = 5 V 12 10 8 6 4 2 0 0 5 10 15 20 25 Ta = + 25 ° C CTL = 5 V VREF = 0 mA 10 8 6 4 2 0 0 5 10 15 20 25 Ta = + 25 ° C VCC = 19 V CTL = 5 V 10 8 6 4 2 0 0 5 10 15 20 25 30 2.0 1.5 1.0 0.5 0.0 − 0.5 − 1.0 − 1.5 − 2.0 − 40 − 20 0 20 ...

Page 10 - Triangular wave oscillator; Error amplifier threshold voltage; Triangular wave oscillator frequency

MB3878 10 (Continued) Ta = + 25 ° C VCC = 19 V CTL = 5 V 1 M 100 k 10 k 10 k 100 k 1 M Ta = + 25 ° C CTL = 5 V RT = 47 k Ω 340 330 320 310 300 290 280 270 260 250 240 0 5 10 15 20 25 VCC = 19 V CTL = 5 V RT = 47 k Ω 340 330 320 310 300 290 280 270 260 250 240 − 40 − 20 0 20 40 60 80 100 VCC = 19 V C...

Page 12 - FUNCTIONAL DESCRIPTION; The triangular wave is input to the PWM comparator on the IC.

MB3878 12 ■ ■ ■ ■ FUNCTIONAL DESCRIPTION 1. DC/DC Converter Unit (1) Reference voltage block (Ref) The reference voltage generator uses the voltage supplied from the VCC terminal (pin 18) to generate a tem-perature-compensated, stable voltage (5.0V Typ) used as the reference supply voltage for the I...

Page 13 - Protection Functions; Under voltage lockout protection circuit (UVLO)

MB3878 13 (7) PWM comparator block (PWM Comp.) The PWM comparator circuit is a voltage-pulse width conver ter for controlling the output duty of the erroramplifiers (Error Amp. 1 to Error Amp. 3) depending on their output voltage. The PWM comparator circuit compares the triangular wave generated by ...

Page 14 - SETTING THE CHARGING VOLTAGE; Battery charging voltage:; METHOD OF SETTING THE CHARGING CURRENT; Battery charge current setting voltage : +INE1; METHOD OF SETTING THE SOFT-START TIME; connected the RT

MB3878 14 ■ ■ ■ ■ SETTING THE CHARGING VOLTAGE The charging voltage (DC/DC output voltage) can be set by connecting external voltage setting resistors (R3,R4) to the -INE3 terminal. Be sure to select a resistor value that allows you to ignore the on resistor (70 Ω , 1mA) of the internal FET connecte...

Page 15 - AC ADAPTOR VOLTAGE DETECTION; AC adaptor detected voltage setting: Vth; OPERATION TIMING DIAGRAM; Constant current control

MB3878 15 ■ ■ ■ ■ AC ADAPTOR VOLTAGE DETECTION With an external resistor connected to the +INE2 terminal(pin 3), the IC enters the dynamically-controlledcharging mode to reduce the charge current to keep AC adaptor power constant when the partial potential pointA of the AC adaptor voltage (Vcc) beco...

Page 16 - Open

MB3878 16 ■ ■ ■ ■ PROCESSING WITHOUT USE OF THE CS PIN If the soft-start function is not used, the CS terminal (pin 22) should be left open. When no soft-start time is specified. ■ ■ ■ ■ NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE • Insert a reverse-current preventive diode at one of the th...

Page 17 - APPLICATION EXAMPLE 1

MB3878 17 ■ ■ ■ ■ APPLICATION EXAMPLE 1 + − − + 8 10 13 12 A B 9 + − − + 4 2 24 1 3 × 25 × 25 + + + − 5 20 21 19 − + + + − 11 16 22 17 6 23 14 18 <Current Amp.1> <Error Amp.1> 7 VREF <Current Amp.2> <Error Amp.2> VREF <Error Amp.3> VREF VREF VREF 5.0 V 4.2 V 1 µ A 15 &l...

Page 19 - REFERENCE DATA; BATT voltage; charge voltage

MB3878 19 ■ ■ ■ ■ REFERENCE DATA 100 98 96 94 92 90 88 86 84 82 80 10 m 100 m 1 10 100 98 96 94 92 90 88 86 84 82 80 0 2 4 6 8 10 12 14 16 18 16 14 12 10 8 6 4 2 0 0 1 2 3 4 5 DCC : Dynamically Controlled Charging Dead Battery MODE DCC MODE 20 15 10 5 0 20 15 10 5 0 0 80 120 160 200 t (ms) 40 BATT (...

Page 20 - APPLICATION EXAMPLE 2

MB3878 20 ■ ■ ■ ■ APPLICATION EXAMPLE 2 + − − + 8 10 13 12 A B C D 9 + − + − + − − + 4 2 24 1 3 × 25 × 25 + + + − 5 20 21 19 − + + + − 11 16 22 17 6 23 14 18 <Current Amp.1> <Error Amp.1> 7 VREF <Current Amp.2> <Error Amp.2> VREF <Error Amp.3> VREF VREF VREF 5.0 V 4.2 V...

Page 22 - USAGE PRECAUTIONS; • Take appropriate static electricity measures.; to 1 M; • Do not apply negative voltages.; ORDERING INFORMATION; Part number

MB3878 22 ■ ■ ■ ■ USAGE PRECAUTIONS • Printed circuit board ground lines should be set up with consideration for common impedance. • Take appropriate static electricity measures. • Containers for semiconductor materials should have anti-static protection or be made of conductive material.• After mou...

Page 23 - PACKAGE DIMENSION

MB3878 23 ■ ■ ■ ■ PACKAGE DIMENSION 24-pin plastic SSOP (FPT-24P-M03) Note1: Pins width and pins thickness include plating thickness.Note2: * This dimension does not include resin protrusion. Dimensions in mm (inches) C 2001 FUJITSU LIMITED F24018S-c-3-4 7.75±0.10(.305±.004) 5.60±0.10 7.60±0.20 (.22...

Page 24 - FUJITSU LIMITED; FUJITSU LIMITED Printed in Japan

MB3878 FUJITSU LIMITED All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with FUJITSU salesrepresentatives before ordering. The information and circuit diagrams in this document arepresented as examples of semiconductor device a...

Fujitsu MB3878 - Manual

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Summary

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