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FUJITSU SEMICONDUCTOR DS04-27709-3E DATA SHEET ASSP For Power Supply Applications (Secondary battery) DC/DC Converter IC for Charging Li-ion battery MB3887 DESCRIPTION The MB3887 is a DC/DC converter IC suitable for down-conversion, using pulse-width (PWM) charging and enabling output voltage to be set to any desired level from one cell to four cells.
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MB3887 (Continued) • Output voltage setting using external resistor : 1 cell to 4 cells • High efficiency : 96 (VIN 19 V, Vo 16.8 V) • Wide range of operating supply voltages : 8 V to 25 V • Output voltage setting accuracy : 4.2 V 0.74 (Ta 10 C to 85 C , per cell) •...
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MB3887 ABSOLUTE MAXIMUM RATINGS Rating Parameter Symbol Conditions Unit Power supply voltage VCC, VCC (O) terminal Output current Duty Peak output current Duty) Power dissipation 25 C 740* Storage temperature * : The package is mounted on the dual-sided epoxy board (10 cm 10 cm) .
No warranty is made with respect to uses, operating conditions, or combinations not represented on the data sheet. Users considering application outside the listed conditions are advised to contact their FUJITSU representatives beforehand.
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MB3887 ELECTRICAL CHARACTERISTICS 25 C, VCC 19 V, VCC (O) 19 V, VREF 0 mA) Value Sym- Parameter Conditions Unit 25 C 4.967 5.000 5.041 REF1 Output voltage 10 C to 85 C 4.95 5.00 5.05 REF2 Reference Input stability Line 8 V to 25 V voltage block...
MB3887 25 C, VCC 19 V, VCC (O) 19 V, VREF 0 mA) Value Sym- Parameter Conditions Unit 2 V, Ta 25 C 4.183 4.200 4.225 Threshold voltage 2 V, 4.169 4.200 4.231 10 C to 85 C Input current INE3 INE3 Voltage gain...
MB3887 TYPICAL CHARACTERISTICS Power supply current vs. Power supply voltage Reference voltage vs. Power supply voltage CTL 5 V CTL 5 V VREF 0 mA Power supply voltage V Power supply voltage V Reference voltage vs. I load current Reference voltage vs. Ambient temperature 5.08 VCC 19 V VCC 19 V...
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MB3887 Triangular wave oscillation frequency Triangular wave oscillation frequency vs. Timing resistor vs. Power supply voltage VCC 19 V CTL 5 V CTL 5 V RT 47 k 100 k 10 k 1000 Timing resistor R (k ) Power supply voltage V Triangular wave oscillation frequency Error amplifier threshold voltage vs.
MB3887 Error amplifier gain and phase vs. Frequency VCC 19 V 4.2 V 240 k 10 k 10 k 2.4 k Error Amp1 10 k 10 k (Error Amp2) 10 k 100 k 10 M Frequency f (Hz) Error amplifier gain and phase vs. Frequency VCC 19 V 4.2 V 240 k...
MB3887 (Continued) Power dissipation vs. Ambient temperature Ambient temperature Ta ( C)
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MB3887 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 (5.0 V Typ) used as the reference supply voltage for the IC’s internal circuitry.
MB3887 (7) PWM comparator block (PWM Comp.) The PWM comparator circuit is a voltage-pulse width converter for controlling the output duty of the error amplifiers (Error Amp1 to Error Amp3) depending on their output voltage. The PWM comparator circuit compares the triangular wave generated by the triangular wave oscillator to the error amplifier output voltage and turns on the external output transistor during the interval in which the triangular wave voltage is lower than the error amplifier output voltage.
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MB3887 3. Soft-Start Function Soft-start block (SOFT) Connecting a capacitor to the CS terminal (pin 22) prevents rush currents when the IC is turned on. Using an error amplifier for soft-start detection makes the soft-start time constant, being independent of the output load of the DC/DC converter.
MB3887 METHOD OF SETTING THE SOFT-START TIME For preventing rush current upon activation of IC, the IC allows soft-start using the capacitor (Cs) connected to the CS terminal (pin 22) . When CTL terminal (pin 14) is placed under “H” level and IC is activated (V UVLO threshold voltage) , Q2 is turned off and the external soft-start capacitor (Cs) connected to the CS terminal is charged at 10 A.
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MB3887 AC ADAPTOR VOLTAGE DETECTION • With an external resistor connected to the INE2 terminal (pin 3) , the IC enters the dynamically-controlled charging mode to reduce the charge current to keep AC adapter power constant when the partial potential point A of the AC adapter voltage (VCC) becomes lower than the voltage at the INE2 terminal.
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MB3887 PROCESSING WITHOUT USING THE CURRENT AMP When Current Amp is not used, connect the INC1 terminal (pin 13) , INC2 terminal (pin 24) , INC1 terminal (pin 12) , and INC2 terminal (pin 1) to VREF, and then leave OUTC1 terminal (pin 10) and OUTC2 terminal (pin 2) open.
MB3887 PROCESSING WITHOUT USING OF THE ERROR AMP When Error Amp is not used, leave FB1 terminal (pin 7) , FB2 terminal (pin 5) open and connect the INE1 terminal (pin 8) and INE2 terminal (pin 4) to GND and connect INE1 terminal (pin 9) , and INE2 terminal (pin 3) , to VREF.
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MB3887 PROCESSING WITHOUT USING OF THE CS TERMINAL When soft-start function is not used, leave the CS terminal (pin 22) open. “Open” Connection when soft-start time is not specified NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE • Insert a reverse-current preventive diode at one of the three locations marked * to prevent reverse current from the battery.
MB3887 PARTS LIST COMPONENT ITEM SPECIFICATION VENDOR PARTS No. 30 V, ID 8 A (Max) P-ch FET VISHAY SILICONIX Si4435DY 60 V, ID 0.115 A N-ch FET VISHAY SILICONIX 2N7002E (Max) Diode 0.42 V (Max) , IF ROHM RB053L-30 3.5 A, 31.6 SLF12565T- Inductor 22 H...
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MB3887 REFERENCE DATA Conversion efficiency vs. Charge current Conversion efficiency vs. Charge current (Constant voltage mode) (Constant current mode) 19 V VIN 19 V BATT charge voltage BATT charge voltage set at 12.6 V set at 12.6 V SW ON Efficiency Efficiency BATT...
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MB3887 Conversion efficiency vs. Charge current Conversion efficiency vs. Charge current (Constant current mode) (Constant voltage mode) VIN 19 V VIN 19 V BATT charge voltage BATT charge voltage set at 16.8 V set at 16.8 V SW ON SW ON Efficiency Efficiency BATT...
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MB3887 Switching waveform constant voltage mode Switching waveform constant current mode (set at 12.6 V) (set at 12.6 V, with 10 V) (mV) BATT (mV) BATT VIN 19 V VIN 19 V 98 mVp-p 98 mVp-p BATT BATT 1.5 A BATT BATT 3.0 A ( s)
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MB3887 (Continued) Soft-start operating waveform Discharge operating waveform constant voltage mode constant voltage mode (set at 12.6 V) (set at 12.6 V) BATT BATT BATT 19 V BATT BATT 10.4 ms 19 V BATT 10 12 14 16 18 20 10 12 14 16 18 20 (ms) (ms)
MB3887 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 mounting, printed circuit boards should be stored and shipped in conductive bags or containers. Work platforms, tools, and instruments should be properly grounded.
Details of "A" part +0.20 1.25 –0.10 (Mounting height) +.008 .049 –.004 0.25(.010) 0~8° "A" +0.08 0.65(.026) 0.24 –0.07 0.13(.005) +.003 .009 0.50±0.20 0.10±0.10 –.003 (.020±.008) (.004±.004) (Stand off) 0.60±0.15 (.024±.006) 0.10(.004) 0.10(.004) 2001 FUJITSU LIMITED F24018S-c-3-4 Dimensions in mm (inches) .
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(2) for use requiring extremely high reliability (i.e., submersible repeater and artificial satellite). Please note that Fujitsu will not be liable against you and/or any third party for any claims or damages arising in connection with above-mentioned uses of the products.