ltc4413edd-trpbf Linear Technology Corporation, ltc4413edd-trpbf Datasheet - Page 11

• Manufacturer Part Number: ltc4413edd-trpbf
• Description: Dual 2.6a, 2.5v To 5.5v, Ideal Diodes In 3mm ? 3mm Dfn
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
If the AUX is present when a wall adapter is applied, as the
resistive divider to ENBB rises through the turn-off thresh-
old, the STAT pin voltage falls and MP1 conducts, allowing
the wall adapter to power the load. When the wall adapter
is removed while the AUX supply is present, the load volt-
age falls until the voltage divider at the ENBB pin falls through
its turn-on threshold. Once this occurs, the LTC4413 au-
tomatically connects the AUX supply to the load when the
AUX voltage exceeds the output voltage, causing the STAT
voltage to rise and disabling the external PFET.
When an AUX supply is attached, the voltage divider at
ENBA (R4 and R5) disconnects the battery from the load,
and the auxiliary supply provides load current, unless a
wall adapter is present as described earlier. If the auxiliary
supply is removed, the battery may again power the load,
depending on if a wall adapter is present.
Multiple Battery Charging
Figure 6 illustrates an application circuit for automatic dual
battery charging from a single charger. Whichever battery
has the lower voltage will receive the larger charging
CHARGER
BATTERY
INPUT
3,11
U
1
5
2
4
INA
INB
ENBA
ENBB
GND
LTC4413
ADAPTER
IDEAL
IDEAL
Figure 6
U
WALL
OUTA
OUTB
STAT
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
10
6
4413 F06
9
W
C1: C0805C106K8PAC
C2: C1206C475K8PAC
470k
BAT1
BAT2
V
ENB
Li CC
LTC4059
CC
PROG
STAT IS HIGH
WHEN BAT1
IS CHARGING
GND
LOAD1
LOAD2
BAT
U
R2
100k
Figure 7
1-CELL
Li-Ion
C1
10µF
current until both battery voltages are equal, then both are
charged. While both batteries are charging simultaneously,
the higher capacity battery gets proportionally higher
current from the charger. For Li-Ion batteries, both batter-
ies achieve the float voltage minus the forward regulation
voltage of 20mV. This concept can apply to more than two
batteries. The STAT pin provides information as to when
battery 1 is being charged. For intelligent control, the
ENBA/ENBB pin inputs can be used with a microcontroller
as shown in Figure 4.
Automatic Switchover from a Battery to a Wall
Adapter and Charger
Figure 7 illustrates the LTC4413 performing the function
of automatically switching a load over from a battery to a
wall adapter while controlling an LTC4059 battery charger.
When no wall adapter is present, the LTC4413 connects
the load at OUTA from the Li-Ion battery at INA. In this
condition, the STAT voltage is high, thereby disabling the
battery charger. If a wall adapter of a higher voltage than
the battery is connected to INB, the load voltage rises as
the second ideal diode conducts. As soon as the OUTA
voltage exceeds INA voltage, the BAT is disconnected from
the load and the STAT voltage falls, turning on the LTC4059
battery charger and beginning a charge cycle. If the wall
adapter is removed, the voltage at INB collapses until it is
below the load voltage. When this occurs, the LTC4413
automatically reconnects the battery to the load and the
STAT voltage rises, disabling the LTC4059 battery charger.
One major benefit of this circuit is that when a wall adapter
is present, the user may remove the battery and replace it
without disrupting the load.
3,11
1
2
4
5
INA
ENBA
ENBB
GND
INB
LTC4413
IDEAL
IDEAL
OUTA
OUTB
STAT
9
10
6
R1
560k
4413 F07
C2
4.7µF
TO LOAD
LTC4413
11
4413fa