ACE4054C

500mA/1.5A Standalone Linear Li-Ion Battery Charge

VER 1.2

8

Detailed description

The ACE4054C is a single cell, fully integrated constant current(CC) /constant voltage (CV) Li-ion

battery charger. It can deliver up to 1.5A of charge current with a final float voltage accuracy of

ACE4054C 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 ACE4054C is also capable of operating from a USB power source.

Normal Charge Cycle

The ACE4054C 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

ACE4054C 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:

ACE4054C has a self-temperature-limiting (STL) function, the chip starts to limit its charge current by

reducing VPROG gradually after silicon temperature rises above 70

and ambient

ACE4054C would have the same charge current and

junction temperature as chips without STL function at room temperature. As the ambient temperature

ACE4054C

would reduce its charge current and hence the junction temperature would be much lower. The STL

function helps to improve system reliability.

Charge Termination

The ACE4054C keeps monitoring the PROG pin during the charging process. It terminates the charge

cycle when the charge current falls to 1/10th the programmed value after the final float voltage is reached.

When the PROG pin voltage falls below 100mV for longer than tTERM (typically 1ms), charging is

terminated. The charge current is latched off and the ACE4054C enters standby mode, where the input

supply current drops to 200

μA. (Note: C/10 termination is disabled in trickle charging and thermal limiting

modes).