LP3918 Datasheet, PDF (4/30 Pages) National Semiconductor (TI) – Battery Charge Management and Regulator Unit

Applications Schematic Diagram
Device Description
The LP3918 Charge Management and Regulator Unit is de-
signed to supply charger and voltage output capabilities for
mobile systems, e.g. CDMA handsets. The device provides a
Li-Ion charging function and 7 regulated outputs. Communi-
cation with the device is via an I2C compatible serial interface
that allows function control and status read-back.
The battery charge management section provides a pro-
grammable CC/CV linear charge capability. Following a nor-
mal charge cycle a maintenance mode keeps battery voltage
between programmable levels. Power levels are thermally
regulated to obtain optimum charge levels over the ambient
temperature range.
Charger Features
• Pre-charge, CC, CV and Maintenance modes
• USB Charge 100mA/450mA
• Integrated FET
• Integrated Reverse Current Blocking Diode
• Integrated Sense Resistor
• Thermal regulation
• Charge Current Monitor Output
• Programmable charge current 50mA - 950mA with 50mA
steps
• Default CC mode current 100mA
• Pre-charge current fixed 50mA
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• Termination voltage 4.1V, 4.2V (default), 4.3V, and 4.4V,
accuracy better than +/- 0.5% (typ)
• Restart level 50mV, 100mV, 150mV (default) and 200mV
below Termination voltage
• End of Charge 0.1C (default), 0.15C, 0.2C and 0.25C
• Programmable Enable Control
• Safety timer
• Input voltage operating range 4.5V - 6.0V
• LDO mode on LP3918TL-L option.
REGULATORS
7 Low dropout linear regulators provide programmable volt-
age outputs with current capabilities of 80mA, 150mA and
300mA as given in the table below. LDO1, LDO2 and LDO3
are powered up by default with LDO1 reaching regulation be-
fore LDO2 and LDO3 are started. LDO1, LDO3 and LDO7 can
be disabled/enabled via the serial interface. During power up
LDO1 and LDO2 must reach their regulation voltage detection
point for the device to power up and remain powered. LDO4,
LDO5 and LDO6 have external enable pins and may power
up following LDO2 as determined by their respective enable.
Under voltage lockout oversees device start up with preset
level of 2.85V(typ).
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