LP4056H – 00

Jan.-2019

www.lowpowersemi.com

Page 5 of 7

Preliminary Datasheet

LP4056H

Application Information

The LP4056H is a single cell lithium-ion battery charger using

a constant-current/constant-voltage algorithm. It can deliver

up to 1000mA of charge current (using a good thermal PCB

layout) with a final float voltage accuracy of ±1%(4.2V). The

LP4056H includes an internal P-channel power MOSFET and

thermal regulation circuitry. No blocking diode or external

current sense resistor is required; thus, the basic charger

circuit requires only two external components. Furthermore,

the LP4056H is capable of operating from a USB power

source.

Normal Charge Cycle

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

above the UVLO threshold level and a 1% ISET ram resistor

is connected from the ISET pin to ground or when a battery is

connected to the charger output. If the BAT pin is less than 3V,

the charger enters trickle charge mode. In this mode, the

LP4056H supplies approximately 1/10 of the ISET rammed

value current to bring the battery voltage up to a safe level for

full current charging.

When the BAT pin voltage rises above 3V, the charger enters

constant-current mode, where the ISET rammed charge

current is supplied to the battery. When the BAT pin

approaches the final float voltage, the LP4056H enters

constant-voltage mode and the charge current begins to

decrease. When the charge current drops to 1/10 of the ISET

rammed value, the charge cycle ends.

ISET ramming Charge Current

The charge current is ISET rammed using a single resistor

from the ISET pin to ground. The battery charge current is

1000 times the current out of the ISET pin. The ISET ram

resistor and the charge current are calculated using the

following equations:

The charge current out of the BAT pin can be determined at

any time by monitoring the ISET pin voltage using the

following equation:

Automatic Recharge

Once the charge cycle is terminated, the LP4056H

continuously monitors the voltage on the BAT pin using a

comparator with a 2ms filter time. A charge cycle restarts

when the battery voltage falls below 4.0V (which corresponds

to approximately 80% to 90% battery capacity). This ensures

that the battery is kept at or near a fully charged condition and

eliminates the need for periodic charge cycle initiations.

CHRG output enters a strong pull-down state during recharge

cycles.

Charge Status Indicator (STAT)

The charge status output has two different states: strong

pull-down (~5mA) and high impedance. The strong pull-down

state indicates that the LP4056H is in a charge cycle. High

impedance indicates that the charge cycle complete or the

than 150mV above the BAT pin voltage or insufficient voltage

is applied to the VIN pin. A microprocessor can be used to

distinguish between these two states.

Function

STAT1(pin7)

STAT2(pin6)

Charging

Low

High

Charge END

High

Low

Thermal Limiting

charge current if the die temperature attempts to rise above a

preset value of approximately 125°C. This feature protects the

LP4056H from excessive temperature and allows the user to

push the limits of the power handling capability of a given

circuit board without risk of damaging the LP4056H.

The charge current can be set according to typical (not

worst-case) ambient temperature with the assurance that the

charger will automatically reduce the current in worst-case

conditions.