YB1880 Schematic ( PDF Datasheet ) - YOBON TECHNOLOGIES

Teilenummer	YB1880
Beschreibung	Standalone Linear Lithium Battery Charger
Hersteller	YOBON TECHNOLOGIES
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Gesamt 10 Seiten YB1880 Standalone Linear Lithium Battery Charger Description YB1880 is a complete constant-current & constant voltage linear charger for single cell lithium-ion batteries. Its SOT-23 package and low external component count make YB1880 ideally suited for portable applications. Furthermore, the YB1880 is specifically designed to work within USB power specification. At the same time, YB1880 can also be used in the standalone lithium-ion battery charger. No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charger current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The YB1880 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the YB1880 automatically enters a low current stage, dropping the battery drain current to less than 2μA. The YB1880 can be put into shutdown mode, reducing the supply current to 20μA. Other features include charge current monitor, under-voltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. Typical Application Circuit Features „ Programmable Charge Current Up to 800mA „ No MOSFET, Sense Resistor or Blocking Diode Required „ Constant-Current/Constant-Voltage Operation „ with Thermal Protection to Maximize Charge „ Rate without Risk of Overheating „ Charges Single Cell Li-ion Batteries Directly „ from USB Port „ Preset 4.2V Charge Voltage with +-1% Accuracy „ 20μA Supply Current in Shutdown „ 2.9V Trickle Charge Threshold „ Available Without Trickle Charge „ Soft-Start Limits Inrush Current „ Available in 5-Lead SOT-23 Package „ Pb-free Package Application „ Cellular and Smart Phones „ Microprocessors and DSP Core Supplies „ Wireless and DSL Modems „ PDA „ MP3 Player „ Digital Still and Video Cameras „ Portable Instruments YB1880 Rev.1.0 www.yobon.com.tw 1 Function Block YB1880 Standalone Linear Lithium Battery Charger Operation The YB1880 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The YB1880 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the YB1880 is capable of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the VCC pin rises above the UVLO threshold level and a 1% program resistor is connected from the PROG pin to ground or when a battery is connected to the charger output. If the BAT pin is less than 2.8V, the charger enters trickle charge mode. In this mode, the YB1880 supplies approximately 1/10 the programmed charge current to bring the battery voltage up to a safe level for full current charging. When the BAT pin voltage rises above 2.8V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin approaches the final float voltage (4.2V), the YB1880 enters constant-voltage mode and the charge current begins to decrease. When the charge current drops to 1/10 of the programmed value, the charge cycle ends. YB1880 Rev.1.0 www.yobon.com.tw 6 6 Page
Seiten	Gesamt 10 Seiten
PDF Download	[ YB1880 Schematic.PDF ]

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Teilenummer	Beschreibung	Hersteller
YB1880	Standalone Linear Lithium Battery Charger	YOBON TECHNOLOGIES

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