LP4054H-00

Aug.-2018

www.lowpowersemi.com

Page 6 of 8

Preliminary Datasheet

LP4054H

Thermal Limit

An internal thermal feedback loop reduces the programmed

charge current if the die temperature attempts to rise above a

preset value of approximately 125℃. This feature protects the

LP4054H 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 LP4054H. 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.

Automatic Recharge

Once the charge cycle is terminated, the LP4054H

continuously monitors the voltage on the BAT pin using a

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.

Power Dissipation

The conditions that cause the LP4054H to reduce charge

current through thermal feedback can be approximated by

considering the power dissipated in the IC. Nearly all of this

power dissipation is generated by the internal MOSFET—this

is calculated to be approximately:

VIN Bypass Capacitor

Many types of capacitors can be used for input bypassing;

however, caution must be exercised when using multilayer

ceramic capacitors. Because of the self-resonant and high Q

characteristics of some types of ceramic capacitors, high

voltage transients can be generated under some start-up

conditions, such as connecting the charger input to a live

power source. Adding a 1.5Ω resistor in series with an X5R

ceramic capacitor will minimize start-up voltage transients.

Layout Considerations



For the main current paths as indicated in bold lines,

keep their traces short and wide.



Put the input capacitor as close as possible to the device

pins (VIN and GND).



Connect all analog grounds to a command node and

then connect the command node to the power ground

behind the output capacitors.