MB3887

Manufacturer Part NumberMB3887
DescriptionDC/DC Converter IC
ManufacturerFujitsu
MB3887 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)

MB3887 Summary of contents

  • Page 1

    ... 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. ...

  • Page 2

    ... 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 • Oscillation frequency range • ...

  • 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) : +INC2 GND VCC ( OUT VCC −INE3 FB3 14 : CTL : +INC1 13 (FPT-24P-M03) MB3887 3 ...

  • Page 4

    ... 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 VCC OUT 21 VCC ( GND +INC2 24 4 I/O Descriptions I Current detection amplifier (Current Amp2) input terminal. ...

  • Page 5

    ... Bias + Voltage (V CC <VH> 2.5 V 1.5 V <UVLO> <Error Amp3> VREF (VCC UVLO) 215 kΩ − kΩ − 4.2 V 0.91 V (0.77 V) VREF UVLO VCC 4.2 V <OSC> <REF> <CTL> VREF 5.0 V bias GND VREF MB3887 21 VCC (O) 20 OUT 19 VH − VCC 18 VCC CTL 14 5 ...

  • Page 6

    ... 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 “ THE SEQUENCE OF THE START-UP AND OFF OF THE POWER SUPPLY” for details. ...

  • Page 7

    ... V CTL ⎯ I OUT Duty ≤ OUT ( fosc × Duty) ⎯ f OSC ⎯ ⎯ ⎯ ⎯ C REF ⎯ Ta MB3887 Value Unit Min Typ Max ⎯ −1 ⎯ ⎯ ⎯ − 1 ⎯ ...

  • 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 [SOFT] 4. Oscillation Triangular frequency ...

  • Page 9

    ... IN +INC1 = +INC2 = VCC, −INCH ∆Vin = −100 mV +INC1 = +INC2 = 0 V, 13, I +INCL ∆Vin = −100 mV 24 +INC1 = +INC2 = −INCL ∆Vin = −100 mV MB3887 Value Unit Min Typ Max 4.183 4.200 4.225 V 4.169 4.200 4.231 V −100 −30 ⎯ nA ⎯ ...

  • 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 Standard design value 10 (Ta = +25 °C, VCC = 19 V, VCC ( VREF = 0 mA) ...

  • Page 11

    ... CTL = CTLL VCC = VCC ( VCC = VCC ( CCS CTL = 0 V VCC = VCC ( CTL = 5 V MB3887 Value Unit Min Typ Max ⎯ −400* ⎯ mA ⎯ ⎯ 400* mA ⎯ Ω 6.5 9.8 ⎯ Ω ...

  • Page 12

    ... MB3887 TYPICAL CHARACTERISTICS Power supply current vs. Power supply voltage Power supply voltage V Reference voltage vs. Reference voltage output current Reference voltage output current I CTL terminal current, Reference voltage vs. CTL terminal voltage 1000 ...

  • Page 13

    ... Power supply voltage V Error amplifier threshold voltage vs. Operating ambient temperature 4. 2. kΩ 4.23 2.22 4.21 4.20 4.19 4.18 4.17 4.16 4.15 −40 −20 80 100 0 Operating ambient temperature Ta ( °C) MB3887 = +25 ° CTL kΩ (V) CC VCC = 19 V CTL = 100 (Continued) 13 ...

  • Page 14

    ... 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 − 100 k Frequency f (Hz) Current detection amplifier gain and phase vs. Frequency φ ...

  • 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 ...

  • Page 16

    ... 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. This terminal can also be used to obtain a load current to a maximum of 1mA from the reference voltage VREF terminal (pin 6) ...

  • Page 17

    ... Protection circuit (UVLO) operation function table When UVLO is operating (VCC or VREF voltage is lower than UVLO threshold voltage.) OUTD Hi-Z Power OFF (Standby) ON (Active) −6 V (Typ) as the minimum potential of the output circuit. In the standby CC OUT H MB3887 OUTD Hi ...

  • 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 the output load of the DC/DC converter. SETTING THE CHARGING VOLTAGE The charging voltage (DC/DC output voltage) can be set by connecting external voltage setting resistors (R3, R4) to the − ...

  • Page 19

    ... Soft-start time : ts (time to output 100 %) ( 0.42 × (µ Soft-start time FB3 −INE3 terminal voltage Comparison with Error Amp block − INE3 voltage. VREF 10 µA 10 µA Error Amp3 − 4 Soft-start circuit MB3887 ≥ UVLO threshold voltage UVLO 19 ...

  • 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 A of the AC adapter voltage (VCC) becomes lower than the voltage at the −INE2 terminal. ...

  • Page 21

    ... 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. “Open” Connection when Current Amp is not used −INC1 +INC1 12 +INC2 −INC2 1 10 OUTC1 2 OUTC2 6 VREF MB3887 ...

  • 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 connect +INE1 terminal (pin 9) , and +INE2 terminal (pin VREF. “ ...

  • Page 23

    ... Insert a reverse-current preventive diode at one of the three locations marked * to prevent reverse current from the battery. • When selecting the reverse current prevention diode, be sure to consider the reverse voltage (V current ( the diode. R “Open” VIN VCC( OUT BATT Battery MB3887 ) and reverse R 23 ...

  • 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 the bias from the VH terminal (pin 19) , when there is a period less in the VCC voltage after previously starting up VCC(O) ...

  • Page 25

    ... APPLICATION EXAMPLE MB3887 25 ...

  • Page 26

    ... 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 C10 Ceramics Condenser R1 Resistor R2 Resistor R3 Resistor R4 Resistor R5 Resistor R6 Resistor R7 Resistor R8 Resistor R9 Resistor R10 to R12 Resistor R13 ...

  • Page 27

    ... BATT × × 100 (A) BATT charge voltage V MB3887 ) / (V) BATT Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16 Efficiency η (%) = × BATT BATT × × 100 ...

  • Page 28

    ... MB3887 Conversion efficiency vs. Charge current (Constant voltage mode) 100 100 m BATT charge current I BATT voltage vs. BATT charge current (set BATT (Product of KIKUSUI PLZ-150W Dead Battery MODE Dynamically-Controlled DCC ...

  • Page 29

    ... Switching waveform constant current mode (set at 16.8 V, with +25 °C V (mV) BATT VIN = 19 V BATT = 3.0 A 100 V BATT −100 V ( (µs) MB3887 98 mVp-p V BATT (µs) 96 mVp-p V BATT (µs) (Continued) 29 ...

  • Page 30

    ... MB3887 (Continued) Soft-start operating waveform constant voltage mode (set at 12 (V) BATT 20 = +25 ° VIN Ω BATT 10 ( (V) CTL Soft-start operating waveform constant voltage mode (set at 16 (V) BATT 20 = +25 ° VIN = 12 Ω ...

  • Page 31

    ... 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 31 ...

  • Page 32

    ... 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 include resin protrusion. Note 3) Pins width and pins thickness include plating thickness. ...

  • 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 this document are presented solely for the purpose of reference to show examples of operations and uses of Fujitsu semiconductor device ...