MB3888

Manufacturer Part NumberMB3888
DescriptionDC/DC Converter IC for Charging Li-ion Battery
ManufacturerFuji Electric
MB3888 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
MB3888
DESCRIPTION
The MB3888 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.
The MB3888 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
• Output voltage setting using external resistor : 1 cell to 4 cells
• High efficiency
• Wide range of operating supply voltages
• Output voltage setting accuracy
• Charging current accuracy
PACKAGE
: 96
(VIN
19 V, Vo
16.8 V)
: 8 V to 25 V
: 5 V
0.74
(Ta
10 C to 85 C)
: 5
20-pin plastic SSOP
(FPT-20P-M03)
DS04-27710-2E
(Continued)

MB3888 Summary of contents

  • Page 1

    ... The MB3888 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. The MB3888 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

    ... MB3888 (Continued) • Built-in frequency setting capacitor enables frequency setting using external resistor only • Oscillation frequency range • Built-in current detection amplifier with wide in-phase input voltage range : • In standby mode, leave output voltage setting resistor open to prevent inefficient current loss • ...

  • Page 3

    ... PIN ASSIGNMENT GND : CTL : 3 VREF : 4 DTC : 5 FB2 : 6 INE2 : 7 INE2 : 8 OUTD : 9 INC : 10 (TOP VIEW VCC ( OUT VCC 15 : FB1 14 : INE1 13 : INE1 12 : OUTC 11 : INC (FPT-20P-M03) MB3888 3 ...

  • Page 4

    ... MB3888 PIN DESCRIPTION Pin No. Symbol 1 GND CTL 4 VREF 5 DTC 6 FB2 7 INE2 8 INE2 9 OUTD 10 INC 11 INC 12 OUTC 13 INE1 14 INE1 15 FB1 16 VCC OUT 19 VCC ( I/O Descriptions Ground terminal. Triangular-wave oscillation frequency setting resistor connection terminal. Power supply control terminal. I Setting the CTL terminal at “L” level places the IC in the standby mode ...

  • Page 5

    ... Error Amp2 VREF INE2 7 INE2 8 FB2 6 DTC 5 OUTD 9 VREF SOFT PWM Comp. OUT Drive VCC VH Bias Voltage UVLO VCC UVLO VREF UVLO 2.5 V 1.5 V OSC REF CTL 45 pF bias VREF GND MB3888 19 VCC (O) 18 OUT VCC 3 CTL 5 ...

  • Page 6

    ... MB3888 ABSOLUTE MAXIMUM RAGINGS Parameter Symbol Power supply voltage V CC Output current I OUT Peak output current I OUT Power dissipation P Storage temperature T STG * : The package is mounted on the dual-sided epoxy board (10 cm WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings. ...

  • Page 7

    ... FUJITSU representatives beforehand. Conditions Min VCC, VCC (O) terminal INE and INE terminal 0 INC and INC terminal 0 DTC terminal Duty 5 600 (t 1 fosc Duty) 100 27 30 MB3888 Rating Unit Typ Max 1 0 ...

  • Page 8

    ... MB3888 ELECTRICAL CHARACTERISTICS Parameter Output voltage 1. Reference Input stability voltage Load stability block [REF] Short-circuit output current Threshold 2. voltage Under voltage lockout Hysteresis width protection Threshold circuit block voltage [UVLO] Hysteresis width 3. Soft-start Charge current block [SOFT] 4. Oscillation Triangular frequency waveform ...

  • Page 9

    ... OUTC3 Vin 100 mV INC OUTC4 Vin 10 INC Vin 100 mV MB3888 19 V, VCC ( VREF 0 mA) Rating Unit Min Typ Max 100 30 nA 100 MHz 4.7 4 200 mV ...

  • Page 10

    ... MB3888 (Continued) Parameter Frequency bandwidth 6. Current Output voltage detection amplifier block Output source [Current Amp] current Output sink current 7. PWM Threshold voltage comparator block [PWM Comp.] Input bias current Output source current Output sink current 8. Output block Output ON resistor [OUT] Rise time ...

  • Page 11

    ... Reference voltage vs. Ambient temperature 5. 5.04 VCC 19 V 5.03 CTL 5 V 5.02 5.01 5.00 4.99 4.98 4.97 4.96 4. Ambient temperature (V) CTL MB3888 CTL 5 V VREF (V) CC VCC 19 V CTL 5 V VREF 100 (Continued) 11 ...

  • Page 12

    ... MB3888 Triangular wave oscillation frequency vs. Timing resistor 1 M 100 100 Timing resistor R Triangular wave oscillation frequency vs. Ambient temperature 320 315 310 305 300 295 290 285 280 275 270 265 260 Ambient temperature Triangular wave oscillation frequency vs. ...

  • Page 13

    ... F 2 2.5 V 180 180 180 100 MB3888 VCC 19 V 4.2 V 240 k ( (6) OUT 13 (8) Error Amp1 10 k (Error Amp2) VCC OUT 10 Current Amp 16 ...

  • Page 14

    ... MB3888 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 16) 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 from the reference voltage VREF terminal (pin 4) ...

  • Page 15

    ... Connecting a capacitor to the CS terminal (pin 20) prevents surge 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. Power OFF (Standby) ON (Active (Typ) as the minimum potential of the output circuit. In the standby OUT H MB3888 OUTD Hi ...

  • Page 16

    ... MB3888 SETTING THE CHARGING VOLTAGE The charging voltage (DC/DC output voltage) can be set by connecting external voltage setting resistors (R3, R4) to the INE2 terminal (pin 7) according to the voltage at the INE2 terminal (pin sure to select a resistor value that allows you to ignore the on resistor ( mA) of the internal FET connected to the OUTD terminal (pin 9) ...

  • Page 17

    ... INE2 CS 20 INE2 4.2 V START TIME - CC ) connected to the CS terminal is charged 4 terminal voltage Comparison with Error Amp block INE2 voltage. VREF Error Amp2 Q2 Soft-start circuit MB3888 ) connected to S UVLO threshold voltage INE2) , FB2 is determined UVLO 17 ...

  • Page 18

    ... MB3888 (2) Setting constant current mode soft-start For preventing rush current upon activation of IC, the IC allows soft-start using the capacitor (C the CS terminal (pin 20) . When CTL terminal (pin 3) is placed under “H” level and IC is activated (V turned off and the external soft-start capacitor (C ...

  • Page 19

    ... PROCESSING WITHOUT USING OF THE DTC TERMINAL When external duty control is not performed using DTC terminal, make a short circuit between the DTC terminal (pin 5) and VREF terminal (pin 4) with a shortest-possible wire. VREF “Open” DTC When DTC terminal is not used MB3888 19 ...

  • Page 20

    ... MB3888 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. • When selecting the reverse current prevention diode, be sure to consider the reverse voltage (V current ( the diode ...

  • Page 21

    ... APPLICATION EXAMPLE MB3888 21 ...

  • Page 22

    ... MB3888 PARTS LIST COMPONENT ITEM Q1 P-ch FET Q2 N-ch FET D1 Diode L1 Inductor C2, C3 Electrolytic condenser C Ceramics Condenser S C5 Ceramics Condenser C6 Ceramics Condenser C7 Ceramics Condenser C9 Ceramics Condenser C10 Ceramics Condenser C11, C12 Ceramics Condenser R Resistor S R Resistor T R3 Resistor R5 Resistor R6 Resistor R8 Resistor R9 Resistor R12 Resistor ...

  • Page 23

    ... (%) I ) BATT 100 (A) BATT charge voltage V MB3888 ) (V) BATT VIN 19 V BATT charge voltage set at 16.8 V SW1 SW2 ON Efficiency (%) ( BATT BATT / ( 100 IN IN ...

  • Page 24

    ... MB3888 BATT voltage vs. BATT charge current (set at 12 VIN BATT Electronic load 14 (Product of KIKUSUI PLZ-150W) 12 Resume Dead 10 MODE Battery MODE (SW1 = ON, (SW1 = OFF, SW2 = OFF) 8 SW2 = ON 0.5 1 1.5 2 2.5 BATT charge current I 24 BATT voltage vs. BATT charge current ...

  • Page 25

    ... Switching waveform constant current mode (set at 16.8 V, with (mV) BATT VIN 19 V 100 BATT 3 BATT 100 V ( MB3888 118 mVp-p V BATT mVp-p V BATT (Continued) 25 ...

  • Page 26

    ... MB3888 Soft-start operating waveform constant voltage mode (set at 12 (V) BATT VIN BATT ( 9 (V) CTL Soft-start operating waveform constant current mode (set at 12 (V) BATT 20 Ta ...

  • Page 27

    ... V BATT ( ( (V) V CTL CTL V CTL (ms) MB3888 V BATT I ( VIN 19 V BATT (ms) V BATT I ( VIN 19 V BATT 4 ...

  • Page 28

    ... Working personnel should be grounded with resistance of 250 k • 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 MB3888PFV between body and ground. Package 20-pin plastic SSOP (FPT-20P-M03) ...

  • Page 29

    ... Details of "A" part 10 "A" 0.13(.005) M 0.50±0.20 (.020±.008) 0.45/0.75 (.018/.030) MB3888 +0.20 1.25 –0.10 (Mounting height) +.008 .049 –.004 0~8° 0.10±0.10 (Stand off) (.004±.004) 0.25(.010) Dimensions in mm (inches) 29 ...

  • Page 30

    ... MB3888 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. Also, ...