MB3887PFV

Manufacturer Part NumberMB3887PFV
DescriptionDC/DC Converter IC for Charging Li-ion battery
ManufacturerFUJITSU [Fujitsu Component Limited.]
MB3887PFV datasheet
 


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FUJITSU SEMICONDUCTOR
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.
These ICs can dynamically control the secondary battery’s charge current by detecting a voltage drop in an AC
adapter in order to keep its power constant (dynamically-controlled charging) .
The charging method enables quick charging, for example, with the AC adapter during operation of a notebook PC.
The MB3887 provides a broad power supply voltage range and low standby current as well as high efficiency,
making it ideal for use as a built-in charging device in products such as notebook PC.
This product is covered by US Patent Number 6,147,477.
FEATURES
• Detecting a voltage drop in the AC adapter and dynamically controlling the charge current
(Dynamically-controlled charging)
PACKAGE
24-pin plastic SSOP
(FPT-24P-M03)
DS04-27709-4E
(Continued)

MB3887PFV Summary of contents

  • Page 1

    FUJITSU SEMICONDUCTOR 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 ...

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    MB3887 (Continued) • Output voltage setting using external resistor • High efficiency • Wide range of operating supply voltages • Output voltage setting accuracy • Charging current accuracy • Built-in frequency setting capacitor enables frequency setting using external resistor only ...

  • Page 3

    PIN ASSIGNMENT −INC2 : 1 OUTC2 : 2 +INE2 : 3 −INE2 : 4 FB2 : 5 VREF : 6 FB1 : 7 −INE1 : 8 +INE1 : 9 OUTC1 : 10 OUTD : 11 −INC1 : 12 (TOP VIEW) ...

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    MB3887 PIN DESCRIPTION Pin No. Symbol −INC2 1 2 OUTC2 +INE2 3 −INE2 4 5 FB2 6 VREF 7 FB1 −INE1 8 +INE1 9 10 OUTC1 11 OUTD −INC1 12 +INC1 13 14 CTL 15 FB3 −INE3 ...

  • Page 5

    BLOCK DIAGRAM −INE1 8 10 OUTC1 <Current Amp1> + +INC1 13 × 20 − −INC1 12 +INE1 9 7 FB1 −INE2 4 2 OUTC2 <Current Amp2> + +INC2 24 × 20 − −INC2 1 +INE2 3 FB2 5 −INE3 16 ...

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    MB3887 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Power supply voltage Output current Peak output current Power dissipation Storage temperature *1 : The package is mounted on the dual-sided epoxy board (10 cm × Refer to “ ...

  • Page 7

    RECOMMENDED OPERATING CONDITIONS Parameter Symbol Power supply voltage Reference voltage output current VH terminal output current Input voltage OUTD terminal output voltage OUTD terminal output current CTL terminal input voltage Output current Peak output current Oscillation frequency Timing resistor Soft-start ...

  • Page 8

    MB3887 ELECTRICAL CHARACTERISTICS Parameter Output voltage 1. Reference Input stability voltage block Load stability [REF] Short-circuit output current Threshold voltage 2. Under voltage lockout protec- Hysteresis width tion circuit block Threshold voltage [UVLO] Hysteresis width 3. Soft-start block Charge current ...

  • Page 9

    Parameter Threshold voltage Input current Voltage gain Frequency bandwidth 5-2. Error amplifier Output voltage block [Error Amp3] Output source current Output sink current OUTD terminal output leak current OUTD terminal output ON resistor Input offset voltage 6. Current detec- tion ...

  • Page 10

    MB3887 Parameter Current detection voltage 6. Current detection In-phase input amplifier block voltage range [Current Amp1, Current Amp2] Voltage gain Frequency bandwidth Output voltage Output source current Output sink cur- rent 7. PWM comparator Threshold voltage block [PWM Comp.] * ...

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    Parameter Output source current Output sink current 8. Output ON Output block resistor [OUT] Rise time Fall time CTL input voltage 9. Control block [CTL] Input current 10. Bias voltage Output voltage block [VH] Standby current 11. General Power ...

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    MB3887 TYPICAL CHARACTERISTICS Power supply current vs. Power supply voltage Power supply voltage V Reference voltage vs. Reference voltage output current ...

  • Page 13

    Triangular wave oscillation frequency vs. Timing resistor VCC CTL 100 100 Timing resistor R (kΩ) T Triangular wave oscillation frequency vs. Operating ambient temperature 320 VCC 315 CTL 310 RT 305 300 295 ...

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    MB3887 Error amplifier gain and phase vs. Frequency 40 φ −20 − 100 k Frequency f (Hz) Error amplifier gain and phase vs. Frequency 40 φ −20 − ...

  • Page 15

    Power dissipation vs. Operating ambient temperature 800 740 700 600 500 400 300 200 100 0 −40 − Operating ambient temperature Ta ( °C) MB3887 100 15 ...

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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 ...

  • Page 17

    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 ...

  • Page 18

    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 ...

  • Page 19

    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 ...

  • Page 20

    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 ...

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    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 ...

  • Page 22

    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 ...

  • Page 23

    PROCESSING WITHOUT USING OF THE CS TERMINAL When soft-start function is not used, leave the CS terminal (pin 22) open. Connection when soft-start time is not specified NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE • Insert a reverse-current preventive diode ...

  • Page 24

    MB3887 THE SEQUENCE OF THE START-UP AND OFF OF THE POWER SUPPLY Please start up and off the VCC terminal (pin 18) and VCC(O) terminal (pin 21) of the power supply terminal at the same time occurrence of ...

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    APPLICATION EXAMPLE MB3887 25 ...

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    MB3887 PARTS LIST COMPONENT ITEM Q1 P-ch FET Q2 N-ch FET D1 Diode L1 Inductor C1 OS-CON TM C2, C3 Electrolytic Condenser C4 Ceramics Condenser C5 Ceramics Condenser C6 Ceramics Condenser C7 Ceramics Condenser C8 Ceramics Condenser C9 Ceramics Condenser ...

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    REFERENCE DATA Conversion efficiency vs. Charge current (Constant voltage mode) 100 Ta = +25 °C 98 VIN = 19 V BATT charge voltage = 96 set at 12 Efficiency η (%) = 92 × (V ...

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    MB3887 Conversion efficiency vs. Charge current (Constant voltage mode) 100 100 m BATT charge current I BATT voltage vs. BATT charge current (set at 12 ...

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    Switching waveform constant voltage mode (set at 12 +25 °C V (mV) BATT VIN = 19 V 100 98 mVp-p BATT = 1 −100 V ( ...

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    MB3887 (Continued) Soft-start operating waveform constant voltage mode (set at 12 (V) BATT 20 = +25 ° VIN Ω BATT 10 ( ...

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    ... Working personnel should be grounded with resistance of 250 kΩ MΩ between body and ground. • Do not apply negative voltages. • The use of negative voltages below −0.3 V may create parasitic transistors on LSI lines, which can cause malfunction. ORDERING INFORMATION Part number MB3887PFV Package 24-pin plastic SSOP (FPT-24P-M03) MB3887 Remarks ...

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    MB3887 PACKAGE DIMENSION 24-pin plastic SSOP (FPT-24P-M03) INDEX 1 0.65(.026) 0.24 .009 0.10(.004) 0.10(.004) 2003 FUJITSU LIMITED F24018S-c-4-5 32 Note Resin protrusion. (Each side : +0.15 (.006) Max) . Note These dimensions do not ...

  • Page 33

    MB3887 FUJITSU LIMITED All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with FUJITSU sales representatives before ordering. The information, such as descriptions of function and application circuit examples, in ...