Fujitsu MB3887 manual Description, Features, Package

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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.

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)

(Continued)

■PACKAGE

24-pin plastic SSOP

(FPT-24P-M03)

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Contents Description FeaturesPackage MB3887 TOP View PIN AssignmentPIN Description Pin No Symbol DescriptionsBlock Diagram Absolute Maximum Ratings Parameter Symbol Conditions Rating Unit Min MaxRecommended Operating Conditions Parameter Symbol Conditions Value Unit Min TypParameter Sym Pin Conditions Electrical CharacteristicsBol Min Typ Parameter Sym Pin Conditions Value Unit Bol Min Typ Max Parameter Sym Pin Conditions Value Unit Bol Min Typ OUT = −45 mA Output block Resistor Typical Characteristics Triangular wave oscillation frequency fOSC kHz Error amplifier gain and phase vs. Frequency Gain a Power dissipation vs. Ambient temperature Functional Description PWM comparator block PWM Comp PowerOutput block OUT Control block CTLMethod of Setting the Charging Current Setting the Charging VoltageMethod of Setting the Triangular Wave Oscillation Frequency Soft-start block SoftMethod of Setting the SOFT-START Time AC Adaptor Voltage Detection Operation Timing DiagramConnection when Current Amp is not used Processing Without Using the Current AMPConnection when Error Amp is not used Processing Without Using of the Error AMPConnection when soft-start time is not specified Processing Without Using of the CS TerminalAt 4 cell Application ExampleParts No Parts ListReference Data Batt Vbatt mV Ta = +25 C, VIN = 19 Batt = 12 Ω Ordering Information Usage PrecautionsPart number Package Remarks Index Package DimensionFujitsu Limited