ACE4559P

150mA Single Cell Li-ion Battery Charger, 0.1mA Termination, 45nA Battery leakage Current

VER 1.1

13

Application Informations

Stability Considerations

The constant-voltage mode feedback loop is stable without an output capacitor provided a battery is

connected to the charge output. With no battery present, an output capacitor is recommended to reduce

ripple voltage.

In constant-current mode, the PROG pin is in the feedback loop, not the battery. The constant-current

mode stability is affected by the impedance at the PROG pin. With no additional capacitance on the

PROG pin, the charger

is stable with program resistor values as high as 100KΩ. However, additional

capacitance on this node reduces the maximum allowed program resistor thus it should be avoided.

Power Dissipation

ACE4559P has low temperature coefficient, at higher temperatures, the charging current will decrease

slightly. To -40℃~125℃ temperature range the change of the charging current is very small. Nearly all of

this power dissipation is generated by the internal MOSFET. This is calculated to be approximately:

Maximum allowable power dissipation limited by the packaging format and cooling conditions in actual

battery voltage is rising gradually, so the power dissipation is reduce accordingly. The power dissipation

turn into heat, please taken into consideration when design system.

VCC Bypass Capacitor

Many types of capacitors can be used for input bypass, 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, a 10uF/16V ceramic capacitor is recommended for this bypass capacitor. Due to a

high voltage transient will be generated under some start-up conditions, such as connecting the charger

input to a live power source.

Charge Current Soft-Start

The ACE4559P includes a soft-start circuit to minimize the inrush current at the start of a charge cycle.

When a charge cycle is initiated, the charge current ramps from zero to the full-scale current over a period

of approximately 190us. This has the effect of minimizing the transient current load on the power supply

during start-up.