LP4065-00

Aug.-2018

www.lowpowersemi.com

Page 6 of 8

Preliminary Datasheet

LP4065

Application Information

Input Voltage Range

The LP4065 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.

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

above the 4.4V 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 LP4065 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 LP4065

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 (1/10).

Charge Termination

A charge cycle is terminated when the charge current falls to

1/10th the ISET programmed value after the final float voltage

is reached. This condition is detected by using an internal,

filtered comparator to monitor the ISET pin. When the ISET

1ms), charging is terminated.

ISET programming Charge Current

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

charge current and the programming resistance is established

Automatic Recharge

Once the charge cycle is terminated, the LP4065 continuously

monitors the voltage on the BAT pin. A charge cycle restarts

when the battery voltage falls below 4.05V (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.

Enable Function

The LP4065 features an enable/disable function. An input

“Low” signal at EN pin or if this pin is floating will enable the IC.

To assure the charger will switch on, the EN turn on control

level must below 0.4 volts. The charger IC will go into the

shutdown mode when the voltage on the EN pin is greater

than 1.4 volts. If the enable function is not needed in a specific

application, it may be tied to GND or floating to keep the

charge IC in a continuously on state.

Charge Status Indicator(CHRG&PG)

After application of a 5V source, the input voltage rises above

the UVLO and sleep thresholds (VIN>VBAT+VDT),but is less

than OVP (VIN<VOVP), then the PG turns on and provides a

low impedance path to ground.

CHRG has two different states: strong pull-down (~5mA) and

high impedance. The strong pull-down state indicates that the

LP4065A is in a charge cycle. When the charger is entered

CV mode and Once the charge current has reduced to the

battery full charge current threshold (IBF), the CHRG pin will

become high impedance.

Function

CHRG

Charging

High

Charge Finish

Low

Function

PG

VIN<UVLO

High

UVLO<VIN<OVP

Low

OVP<VIN

High