LP3923

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SNVS567B – APRIL 2010 – REVISED MAY 2013

Table 1. LP3923 PIN DESCRIPTIONS(1) (continued)

E2

HF_PWR

DI

Power up sequence starts when this pin is set HIGH. Internal 500 k

Ω pull-

down resistor.

E3

PWR_ON

DI

Power up sequence starts when this pin is set HIGH.

Internal 500 k

Ω pull-down resistor.

E4

SCL

DI

Serial Interface Clock input.

External pull up resistor is needed, typ. 1.5 k

Ω.

E5

BATT

P

Main battery connection. Used both as a power connection for current

delivery to the battery and as a voltage sense connection to monitor the

battery charge level.

F1

VINB

P

Input for Buck

F2

GNDB

G

Power Ground for Buck

F3

FB

A

Buck Feedback pin

F4

ACOK_N

DO

F5

CHG_IN

P

DC power input to charger block from AC adapter or USB

Device Description

The LP3923 Charge Management and Regulator Unit is designed to supply charger and voltage output

capabilities for mobile systems, e.g. CDMA handsets. The device provides a Li-Ion charging function and 8 or 9

control and status read-back.

The battery charge management section provides a programmable CC/CV linear charge capability and end of

charging current threshold. Following a normal charge cycle a maintenance mode utilizing programmable restart

voltage levels enables the battery voltage to be maintained at the correct level. Power dissipation is thermally

regulated to obtain optimum charge levels over the ambient temperature range.

CHARGER FEATURES

•

Pre-charge, CC, CV and Maintenance modes

•

Integrated FET

•

Integrated Reverse Current Blocking Diode

•

Integrated Sense Resistor

•

Thermal Regulation

•

Charging Current Monitor Output

•

Programmable charging current 50 mA - 1200 mA with 50 mA steps

•

Default CC mode current 400 mA

•

Pre-charging current fixed 50 mA

•

Termination voltage 4.1V, 4.2V (default), 4.3V and 4.4V

•

Restart level 50 mV, 100 mV (default), 150 mV and 200 mV below Termination voltage

•

End of Charge 0.05C, 0.1C, 0.15C (default) and 0.2C

•

Input voltage operating range 4.5 - 6.8V

REGULATORS

Eight low dropout linear regulators provide programmable voltage outputs with current capabilities of 80 mA, 150

mA, and 300 mA as given in the table below. LDO1 and LDO2 are supplied either by the VBATT (SEL=GND) or

by buck regulator’s output (SEL=VBATT). If the supply voltage is low (supply from buck), then LDO1 and LDO2

are going to be low-input low-output (LILO) LDOs.

Buck regulator can provide 700 mA (typ.) of current. If the buck is used for supplying LDO1 and LDO2 it won’t be

able to supply external devices. If LDO1 and LDO2 are supplied by VBATT, then buck can be used as an output

power channel for digital loading with the default output voltage value of 1.8V

Under voltage lockout oversees device start up with a preset level of 3.0V( typ.).

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