ACE4703 datasheet(11/15 Pages) ACE

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ACE4703

Fully 5A, 3cell Standalone Li-ion Battery Charger

VER 1.2

Where:

Pd is the power dissipation of the power MOSFET

VBAT is the maximum battery voltage

VCC is the minimum input voltage

Rds(on) is the power MOSFET’s on resistance at room temperature

ICH is the charge current

dT is the temperature difference between actual ambient temperature and room temperature(25℃)

In addition to the I

2Rds(on) loss, the power MOSFET still has transition loss, which are highest at the

highest input voltage. Generally speaking, for VIN＜20V, the I

2Rds(on) loss may be dominant, so the

MOSFET with lower Rds(on) should be selected for better efficiency; for VIN＞20V, the transition loss

may be dominant, so the MOSFET with lower CRSS can provide better efficiency. CRSS is usually specified

in the MOSFET characteristics; if not, then CRSS can be calculated using CRSS = QGD/ΔVDS.

The MOSFETs such as AO4459, STM9435(or WT9435), AO3407A can be used. The part numbers

listed above are for reference only, the users can select the right MOSFET based on their requirements.

Diode Selection

The diodes D1 and D2 in Figure 1 are schottky diode, the current rating of the diodes should be at least

the charge current limit, the voltage rating of the diode should exceed the maximum expected input

voltage. The diode that is much larger than that is sufficient can result in larger transition losses due to

their larger junction capacitance.

Disable Charging with TEMP Pin

The charging can be disabled with TEMP pin, as shown in Figure 3：

ACE4703

Note: M1 is N-Channel MOSFET

Figure 3

Disable Charging With TEMP Pin

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