FUJITSU SEMICONDUCTOR DATA SHEET DS04-27709-3E 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.
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.
MB3887 ■ PIN ASSIGNMENT (TOP VIEW) 24 : +INC2 −INC2 : 1 23 : GND OUTC2 : 2 +INE2 : 3 22 : CS −INE2 : 4 21 : VCC (O) 20 : OUT FB2 : 5 19 : VH VREF : 6 18 : VCC FB1 : 7 −INE1 : 8 17 : RT +INE1 : 9 16 : −INE3 OUTC1 : 10 15 : FB3 OUTD : 11 14 : CTL −INC1 : 12 13 : +INC1 (FPT-24P-M03) 3
MB3887 ■ PIN DESCRIPTION 4 Pin No. Symbol I/O Descriptions 1 −INC2 I Current detection amplifier (Current Amp2) input terminal. 2 OUTC2 O Current detection amplifier (Current Amp2) output terminal. 3 +INE2 I Error amplifier (Error Amp2) non-inverted input terminal. 4 −INE2 I Error amplifier (Error Amp2) inverted input terminal. 5 FB2 O Error amplifier (Error Amp2) output terminal. 6 VREF O Reference voltage output terminal.
MB3887 ■ BLOCK DIAGRAM −INE1 8 OUTC1 10 + × 20 − −INC1 12 +INC1 13 VREF − + 21 VCC (O) +INE1 9 + + + Drive − FB1 7 −INE2 4 OUTC2 2 + +INC2 24 × 20 − −INC2 1 +INE2 3 VREF VCC − VCC (VCC UVLO) 215 kΩ + − + + − 4.2 V FB3 15 (VCC − 6 V) 2.5 V 1.5 V VREF OUTD 11 19 VH Bias Voltage + FB2 5 −INE3 16 20 OUT 35 kΩ 0.91 V (0.77 V) VREF UVLO VREF 10 µA VCC 4.
MB3887 ■ ABSOLUTE MAXIMUM RATINGS Parameter Symbol Conditions Power supply voltage VCC Output current IOUT Peak output current IOUT Power dissipation PD Storage temperature TSTG Rating Unit Min Max VCC, VCC (O) terminal 28 V 60 mA Duty ≤ 5 % (t = 1 / fOSC × Duty) 700 mA Ta ≤ +25 °C 740* mW −55 +125 °C * : The package is mounted on the dual-sided epoxy board (10 cm × 10 cm) .
MB3887 ■ RECOMMENDED OPERATING CONDITIONS Parameter Symbol Conditions VCC, VCC (O) terminal Value Unit Min Typ Max 8 25 V Power supply voltage VCC Reference voltage output current IREF −1 0 mA VH terminal output current IVH 0 30 mA VINE −INE1 to −INE3, +INE1, +INE2 terminal 0 VCC − 1.
MB3887 ■ ELECTRICAL CHARACTERISTICS (Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) Symbol Pin No. VREF1 6 VREF2 Input stability Load stability Parameter Output voltage 1. Reference voltage block [REF] Short-circuit output current Threshold voltage 2. Under voltage lockout protecHysteresis width tion circuit block Threshold voltage [UVLO] Hysteresis width 3. Soft-start block Charge current [SOFT] 4.
MB3887 (Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) Symbol Pin No. Conditions VTH1 16 VTH2 Input current Parameter Value Unit Min Typ Max FB3 = 2 V, Ta = +25 °C 4.183 4.200 4.225 V 16 FB3 = 2 V, Ta = −10 °C to +85 °C 4.169 4.200 4.231 V IINE3 16 −INE3 = 0 V −100 −30 nA Voltage gain AV 15 DC 100* dB Frequency bandwidth BW 15 AV = 0 dB 2* MHz VFBH 15 4.7 4.
MB3887 (Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) Parameter Current detection voltage 6. Current detection In-phase input amplifier block voltage range [Current Amp1, Current Amp2] Pin No. Conditions Value Unit Min Typ Max +INC1 = +INC2 = VOUTC1 2, 10 3 V to VCC, ∆Vin = −100 mV 1.9 2.0 2.1 V +INC1 = +INC2 = VOUTC2 2, 10 3 V to VCC, ∆Vin = −20 mV 0.34 0.40 0.46 V +INC1 = +INC2 = VOUTC3 2, 10 0 V to 3 V, ∆Vin = −100 mV 1.8 2.0 2.
MB3887 (Continued) (Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA) Symbol Pin No. Conditions ISOURCE 20 ISINK Output ON resistor Parameter Typ Max OUT = 13 V, Duty ≤ 5 % (t = 1 / fOSC × Duty) −400* mA 20 OUT = 19 V, Duty ≤ 5 % (t = 1 / fOSC × Duty) 400* mA ROH 20 OUT = −45 mA 6.5 9.8 Ω ROL 20 OUT = 45 mA 5.0 7.
MB3887 ■ TYPICAL CHARACTERISTICS Reference voltage vs. Power supply voltage 6 6 Ta = +25 °C CTL = 5 V 5 Reference voltage VREF (V) Power supply current ICC (mA) Power supply current vs. Power supply voltage 4 3 2 1 0 0 5 10 15 20 5 4 3 2 0 25 Ta = +25 °C CTL = 5 V VREF = 0 mA 1 0 Power supply voltage VCC (V) Reference voltage VREF (V) Reference voltage VREF (V) 5.08 4 3 2 1 5 10 15 20 25 20 25 30 IREF load current IREF (mA) VCC = 19 V CTL = 5 V 5.06 5.04 5.02 5.00 4.98 4.
MB3887 Triangular wave oscillation frequency vs. Timing resistor 340 Ta = +25 °C VCC = 19 V CTL = 5 V Triangular wave oscillation frequency fOSC (kHz) Triangular wave oscillation frequency fOSC (Hz) 1M Triangular wave oscillation frequency vs. Power supply voltage 100 k 10 k Ta = +25 °C CTL = 5 V RT = 47 kΩ 330 320 310 300 290 280 270 260 10 100 0 1000 Timing resistor RT (kΩ) 0 20 40 60 20 25 80 Ambient temperature Ta ( °C) Error amplifier threshold voltage vs.
MB3887 Error amplifier gain and phase vs. Frequency Ta = +25 °C 40 VCC = 19 V 180 AV φ 90 0 Phase φ (deg) 20 Gain AV (dB) 4.2 V 0 −20 −90 10 kΩ 1 µF + 8 (4) 2.4 kΩ IN − 7 (5) + 9 (3) 10 kΩ −40 240 kΩ 10 kΩ OUT Error Amp1 (Error Amp2) 10 kΩ −180 1k 10 k 100 k 1M 10 M Frequency f (Hz) Error amplifier gain and phase vs. Frequency Ta = +25 °C 40 VCC = 19 V 4.2 V 180 20 90 0 0 −90 −20 240 kΩ 10 kΩ 10 kΩ Phase φ (deg) Gain AV (dB) AV φ 1 µF + 2.
MB3887 (Continued) Power dissipation PD (mW) Power dissipation vs.
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 temperature-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) .
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.
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 −INE3 terminal (pin 16) .
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 (VCC ≥ UVLO threshold voltage) , Q2 is turned off and the external soft-start capacitor (Cs) connected to the CS terminal is charged at 10 µA.
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.
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.
MB3887 ■ PROCESSING WITHOUT USING OF THE CS TERMINAL When soft-start function is not used, leave the CS terminal (pin 22) open. “Open” CS 22 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.
SW Q2 R11 30 kΩ R10 30 kΩ R16 R15 200 kΩ 120 Ω R14 1 kΩ R3 330 kΩ C6 1500 pF C4 0.022 µF 4 16 5 15 CS 22 FB3 11 OUTD −INE3 FB2 VREF 10 µA OUTC2 2 +INC2 + 24 × 20 − 1 −INC2 3 +INE2 R17 100 kΩ R19 100 kΩ R18 200 kΩ R5 330 kΩ R6 68 kΩ C8 10000 pF R7 R4 22 kΩ 82 kΩ −INE2 R8 100 kΩ −INE1 8 OUTC1 10 C10 5600 pF +INC1 A + 13 R9 × 20 −INC1 10 kΩ − B 12 R12 30 kΩ +INE1 9 R13 20 kΩ FB1 7 4.
MB3887 ■ PARTS LIST COMPONENT ITEM SPECIFICATION Q1 Q2 P-ch FET N-ch FET D1 Diode L1 Inductor 22 µH C1 C2, C3 C4 C5 C6 C7 C8 C9 C10 OS-CONTM Electrolytic Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 to R12 R13 R14 R15 R16, R18 R17, R19 Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor
MB3887 ■ REFERENCE DATA Conversion efficiency vs. Charge current (Constant voltage mode) 98 96 94 92 90 88 100 Ta = +25 °C VIN = 19 V BATT charge voltage = set at 12.6 V SW = ON Efficiency η (%) = (VBATT × IBATT) / (VIN × IIN) × 100 Conversion efficiency η (%) Conversion efficiency η (%) 100 Conversion efficiency vs. Charge current (Constant current mode) 86 84 82 80 10 m Ta = +25 °C VIN = 19 V BATT charge voltage = set at 12.
MB3887 Conversion efficiency vs. Charge current (Constant current mode) Conversion efficiency vs. Charge current (Constant voltage mode) 100 Conversion efficiency η (%) Conversion efficiency η (%) 100 98 96 94 92 Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.8 V SW = ON Efficiency η (%) = (VBATT × IBATT) / (VIN × IIN) × 100 90 88 86 84 82 80 10 m 100 m 1 98 96 94 92 Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.
MB3887 Switching waveform constant voltage mode (set at 12.6 V) Ta = +25 °C VIN = 19 V BATT = 1.5 A VBATT (mV) 100 Switching waveform constant current mode (set at 12.6 V, with 10 V) VBATT (mV) Ta = +25 °C VIN = 19 V 100 BATT = 3.0 A 98 mVp-p VBATT 0 VBATT 0 VD −100 VD (V) 15 98 mVp-p VD −100 VD (V) 15 10 10 5 5 0 0 0 1 2 3 4 5 6 7 8 9 10 (µs) Switching waveform constant voltage mode (set at 16.8 V) = +25 °C VBATT (mV) Ta VIN = 19 V 100 BATT = 1.
MB3887 (Continued) Soft-start operating waveform constant voltage mode (set at 12.6 V) Discharge operating waveform constant voltage mode (set at 12.6 V) VBATT (V) 20 VBATT (V) 20 Ta = +25 °C, VIN = 19 V BATT = 12 Ω 10 0 VCS (V) 4 VBATT 10 VBATT VCS ts = 10.
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.
MB3887 ■ 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. 0.17±0.03 (.007±.001) * 7.75±0.10(.305±.004) 24 13 5.60±0.10 7.60±0.20 (.220±.004) (.299±.008) INDEX Details of "A" part +0.20 1.25 –0.10 +.008 .049 –.004 (Mounting height) 0.25(.010) 1 "A" 12 0.65(.026) 0.24 .009 +0.08 –0.07 +.003 –.003 0.13(.005) 0~8° M 0.50±0.20 (.020±.008) 0.60±0.15 (.024±.006) 0.10±0.
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 and circuit diagrams in this document are presented as examples of semiconductor device applications, and are not intended to be incorporated in devices for actual use.