ACE4054

Fully integrated constant current/constant voltage

Li-ion battery charger

VER 1.4

9

Recharge Voltage vs Temperature

Trickle Charge Voltage vs Temperature

T (℃)

T (℃)

Detailed description

The ACE4054 is a single cell, fully integrated constant current (CC) / constant voltage (CV) Li-ion battery

charger. It can deliver up to 600mA of charge current with a final float voltage accuracy of ±1%. The

ACE4054 has a build-in thermal regulation circuitry that ensures its safe operation. No blocking diode or

external current sense resistor is required; hence reduce the external components for a basic charger

circuit to two. The ACE4054 is also capable of operating from a USB power source.

Normal Charge Cycle

The ACE4054 initiates a charge cycle once the voltage at the VCC pin rises above the UVLO threshold

level. A 1% precision resistor needs to be connected from the PROG pin to ground. If the voltage at the

BAT pin is less than 2.9V, the charger enters trickle charge mode. In this mode, the charge current is

reduced to nearly 1/10 the programmed value until the battery voltage is raised to a safe level for full

current charging.

The charger switches to constant-current mode as the BAT pin voltage rises above 2.9V, the charge

current is thus resumed to full programmed value. When the final float voltage (4.2V) is reached the

ACE4054 enters constant-voltage mode and the charge current begins to decrease until it drops to 1/10

of the preset value and ends the charge cycle.

Programming Charge Current

The charge current is programmable by setting the value of a precision resistor connected from the

PROG pin to ground. The charge current is 1000 times of the current out of the PROG pin. The program

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 PROG pin

voltage using the following equation: