LP4066-00

Jan.-2019

www.lowpowersemi.com

Page 6 of 7

Preliminary Datasheet

LP4066

Application Information

Input Voltage Range

The LP4066 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 6.2V.

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 LP4066 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 LP4066

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 LP4066 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.

Charge Status Indicator(CHRG)

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

LP4066A is in a charge cycle. When the charger is entered

CV mode and once the charge current has reduced to the

become high impedance.

Function

CHRG

Charging

High

Charge Finish

Low

Thermal Limiting

programmed charge current if the die temperature attempts to

rise above a preset value of approximately 125°C. This

feature protects the LP4066 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

LP4066. 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.