SE9018 Datasheet, PDF(6/9 Page) Seaward Electronics Inc. – 1A Standalone Linear Li-lon Battery Charger

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SE9018 Datasheet, PDF (6/9 Pages) Seaward Electronics Inc. – 1A Standalone Linear Li-lon Battery Charger

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SE9018

1A Standalone Linear Li-lon Battery Charger

Applications

The SE9018 is a complete constant âcurrent & the battery approaches the regulation voltage 4.2V,

constant-voltage linear charger for single cell the charge current begins to decrease as the

lithium-ion batteries. Constant-current & constant - SE9018 enters the constant-voltage mode. When

voltage to charger batter by internal MOSFET .It the current drops to charge termination threshold,

can deliver up to 1A of charge current .No blocking the charge cycle is terminated, and CHRG pin

diode or external current sense resistor is required. assumes a high impedance state to indicate that the

SE9018 include two Open-Drain charge status charge cycle is terminated and STDBY pin is pulled

Pins: Charge status indicator and battery failure low. The charge termination threshold is 10% of the

status output .The internal thermal regulation current in constant current mode. To restart the

circuit reduces the programmed charge current if charge cycle, remove the input voltage and reapply

the die temperature attempts to rise above a it, or momentarily force CE pin to 0V. The charge

preset value of approximately 145â. This feature cycle can also be automatically restarted if the BAT

protects the SE9018 from excessive temperature, pin voltage falls below the recharge threshold. The

and allows the user to push the limits of the power on-chip reference voltage, error amplifier and the

handling capability of a given circuit board without resistor divider provide

risk of damaging the SE9018 or the external regulation voltage with 1% accuracy which can

components. Another benefit of adopting thermal meet the requirement of lithium-ion and lithium

regulation is that charge current can be set polymer batteries. When the input voltage is not

according to typical, not worst-case, ambient present, or input voltage is below VBAT, the charger

temperatures for a given application with the

goes into a sleep mode, dropping battery drain

assurance that the charger will automatically current to less than 3Î¼A. This greatly reduces the

reduce the current in worst-case conditions.

current drain on the battery and increases the

The charge cycle begins when the voltage at standby time. The charger can be shutdown by

the VCC pin rises above the UVLO level, a current forcing the CE pin to GND.

set resistor is connected from the PROG pin to Programming charge current

ground, and the CE pin is pulled above the chip The charge current is programmed using a single

enable threshold. The CHRG pin outputs a logic resistor from the PROG pin to ground. The program

low to indicate that the charge cycle is on going. At resistor and the charge current are calculated using

the beginning of the charge cycle, if the battery

the following equations.:

voltage is below 2.9V, the charge is in recharge

mode to bring the cell voltage up to a safe level for

charging. The charger goes into the fast charge

constant-current mode once the voltage on the

In application, according the charge current to

BAT pin rises above 2.9 V. In constant current determine RPROG ,the relation between RPROG and

mode, the charge current is set by RPROG. When charge current can reference the following chart:ï¼

Rev1.0

Preliminary and all contents are subject to change without prior notice

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