LP28006 Datasheet, PDF (8/11 Pages) Lowpower Semiconductor inc – Internal Integrate P-MOSFETs

Preliminary Datasheet
LP28006
Application Information
Automatically Power Source Selection
The LP28006 is a battery charger IC which is
designed for Li-ion Battery with 4.2V rated voltage.
ACIN Mode : When the ACIN input voltage is
higher than the UVP voltage level (4.4V), the
LP28006 will turn on ACINP-MOSFET. Sleep
Mode : The LP28006 will enter Sleep Mode when
ACIN input voltage are removed. This feature
provides low leakage current from the battery
during the absence of input supply.
use 10uF if the layout is poor if prevent noise.
ACIN Over Voltage Protection
The ACIN input voltage is monitored by an internal
OVP comparator. The comparator has an accurate
reference of 2.5V from the band-gap reference. The
OVP threshold is set by the internal resistive. The
protection threshold is set to 6.5V. When the input
voltage exceeds the threshold, the comparator
outputs a logic signal to turn off the power
P-MOSFET to prevent the high input voltage from
damaging the electronics in the handheld system.
When the input over voltage condition is removed
(ACIN < 6V), the comparator re-enables the output
by running through the soft-start.
Battery Temperature Monitoring
The LP28006 continuously monitors battery
temperature by measuring the voltage between the
TS and GND pins. The LP28006 has an internal
current source to provide the bias for the most
common 10kΩ negative-temperature coefficient
thermal resistor (NTC) (see Figure 1). The LP28006
compares the voltage on the TS pin against the
internal VTS_HIGH and VTS_LOW thresholds to
determine if charging is allowed.
When the temperature outside the VTS_HIGH and
VTS_LOW thresholds is detected, the device will
immediately stop the charge. The LP28006 stops
charge and keep monitoring the battery temperature
when the temperature sense input voltage is back to
the threshold between VTS_HIGH and VTS_LOW,
the charger will be resumed. Charge is resumed
when the temperature returns to the normal range.
However the user may modify thresholds by the
negative-temperature coefficient thermal resistor or
adding two external resistors. (see Figure 2.)The
capacitor should be placed close to TS(Pin 9) and
connected to the ground plane. The capacitance
value(0.1uF to 10uF) should be selected according
to the quality of PCB layout. It is recommended to
Fast-Charge Current Setting The LP28006 offers
ISETA pin to determine the ACIN charge rate from
100mA to 1.2A. The charge current can be
calculated as following equation.
LP28006 – 00 Ver. 1.0 Datasheet
Feb.-2010
www.lowpowersemi.com
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