LP28013

LP28013 – 01

Aug-2017

www.lowpowersemi.com

Page 5 of 7

Application Information

Input Voltage Range

The LP28013 has built-in input voltage surge protection as

high as +28V. The charger IC will be automatically disabled

when the input voltage is lower than 3.3V or higher than 7.0V.

The open-drain PG Pin is used to indicate an input power

good condition (3.3V<VIN<7.0V). If the input voltage is lower

than the battery voltage, the IC is also disabled to prevent the

battery from draining.

A charge cycle begins when the voltage at the VIN pin rises

above the UVLO threshold level, when a battery is connected

to the charger output. If the BAT pin is less than 2.6V, the

charger enters trickle charge mode. In this mode, the

LP28013 supplies approximately 1/10 the ISET programmed

charge current to bring the battery voltage up to a safe level

for full current charging. When the BAT pin voltage rises

above 2.6V, the charger enters constant-current mode(CC),

where the ISET programmed charge current is supplied to the

battery. When the BAT pin approaches the final float voltage,

the LP28013 enters constant-voltage mode(CV) and the

charge current begins to decrease, and the battery full

indication is set when the charge current in the CV mode is

reduced to the programmed full battery current (IBF).

ISET programming Charge Current

connecting from the ISET pin to GND. The relationship of the

charge current and the programming resistance is established

by the following table.

1.3

1150

1.5

1000

2

700

3.3

420

10

130

Termination charge current programmed

The battery charge Termination current threshold (IBF) is

programmed by connecting a resistor RBF from the IBF pin to

GND:

A charge cycle is terminated when the charge current falls to

IBF programming threshold. The open-drain pin CHRG is

used to indicate charging status. When the battery full

condition is reached or any other condition prevents the

charger from charging, CHRG will become a High impedance

pin.

Battery Temperature Detection

The NTC function for the LP28013 is designed to follow the

new JEITA temperature standard for Li-Ion. There are now

three thresholds, 60°C, 10°C, and 0°C. Normal operation

occurs between 10°C and 60°C. If between 0°C and 10°C the

charge current level is cut in half. Above 60°C or below 0°C

the charge is disabled.

The NTC feature is implemented using an internal 48μA

current source to bias the thermistor connected from the NTC

terminal to GND(designed for use with a 10k NTC β = 3370

[SEMITEC 103AT-2 or Mitsubishi TH05-3H103F]). If NTC

feature is not needed, a fixed 10kΩ can be placed between

current is fixed along with the temperature thresholds, it is not

possible to use thermistor values other than the 10k NTC (at

25°C).