AAT3680 Advanced Analogic Technologies, AAT3680 Datasheet - Page 14

• Manufacturer Part Number: AAT3680
• Description: Lithium-Ion Linear Battery Charge Controller
• Manufacturer: Advanced Analogic Technologies

current rating must be for a given blocking diode.
The minimum power handling capacity must be cal-
culated based on the constant current amplitude
and the diode forward voltage (V
Where:
P
tion
V
I
Schottky Diodes
The reason for selecting a Schottky diode for this
application is because Schottky diodes have a low
forward voltage drop. The forward voltage (V
a Schottky diode is typically between 0.3V and
0.4V. A lower V
14
CC
D(MIN)
F
= Diode forward voltage
= Constant current charge level for the system
= Minimum power rating for a diode selec-
F
P
D(MIN)
permits a lower voltage drop at
= V
F
/ I
CC
F
):
Lithium-Ion Linear Battery Charge Controller
F
) for
the constant current charge level set by the sys-
tem, less power will be dissipated in this element of
the circuit. Schottky diode allow for lower power
dissipation, smaller component package sizes and
greater circuit layout densities.
Rectifier Diodes
Any general purpose rectifier diode can be used
with the AAT3680 application circuit in place of a
higher cost Schottky type diode. The design trade-
off is a rectifier diode has a high forward voltage
drop. V
range of 0.7V. A higher V
voltage requirement for the battery charger sys-
tem. This will also require a higher power rated
diode since the voltage drop at the constant current
charge amplitude will be greater. Refer to the pre-
viously stated equations to calculate the minimum
V
IN
and diode P
F
for a typical silicon rectifier diode is in the
D
for a given application.
F
will place a input supply
AAT3680
3680.2003.4.0.91