A4059
BATTERY MANAGEMENT
AiT Semiconductor Inc.
www.ait-ic.com
PROGRAMMABLE VOLTAGE AND
CURRENT LINEAR BATTERY MANAGEMENT CHIP
The large current output design
Since the A4059 using the internal constant power technology, therefore , when the input VIN and BAT
pressure is too large, will lead to smaller the BAT voltage range of the maximum current , so that the
charging time becomes longer , in order to make the maximum current charging interval larger by an external
resistor or Schottky methods to achieve.
The assumption the A4059 of PSOP8 inside the package the maximum allowable power 1.2W, maximum
charge current is set to 1.2A. If uses a resistive, We assume that the use of the resistance of 0.5Ω (1W),
High current charging, the voltage drop across the resistor is 0.5*1.2=0.6V. The A4059 real operating voltage
is 4.4V. Thus, in this state, (VIN-VBAT) *1.2<1.2W, therefore VBAT>3.6V, the battery voltage is above 3.6V 1.2A
charging support. Below 3.6V, the A4059 will automatically reduce the charge current to maintain the chip
internal power balance.
If Schottky similar calculation can be made , according to the Schottky voltage drop at different current .
In addition , in the high-current applications need to pay attention A4059 PCB layout design must consider
increasing EXPOSED PAD area , and will be connected to the EXPOSED PAD to GND in order to improve
the thermal performance , and ensure the stable operation of the chip .
REV1.0 - OCT 2013 RELEASED -
- 10 -
AITSEMI [ AiT Semiconductor ]
