Datasheet

LTC4413
9
4413fc
APPLICATIONS INFORMATION
For short durations after the output is shorted, the
current may exceed I
MAX
. The magnitude of this peak
short-circuit current can be large, depending on the load
current immediately before the short circuit occurs. During
overcurrent operation, the power consumption of the
LTC4413 is large, and is likely to cause an overtemperature
condition as the internal die temperature exceeds the
thermal shutdown temperature.
Overtemperature Protection
The overtemperature condition is detected when the
internal die temperature increases beyond 150°C. An
overtemperature condition causes the gate amplifi ers (A
and B) as well as the two P-channel MOSFETs (PA and
PB) to be shut off. When the internal die temperature
cools to below 140°C, the amplifi ers turn on and revert
to normal operation. Note that prolonged operation under
overtemperature conditions degrades reliability.
Channel Selection and Status Output
Two active-high control pins independently turn off the
two ideal diodes contained within the LTC4413, control-
ling the operation mode as described by Table 1. When
the selected channel is reverse biased, or the LTC4413 is
put into low power standby, the status signal indicates
this condition with a low voltage.
Table 1. Mode Control
ENB1 ENB2 STATE
Low Low Diode OR (NB: The Two Outputs Are Not Connected
Internal to the Device)
Low High Diode A = Enabled, Diode B = Disabled
High Low Diode A = Disabled, Diode B = Enabled
High High All 0ff (Low Power Standby)
The function of the STAT pin depends on the mode that
has been selected. The following table describes the STAT
pin output current as a function of the mode selected, as
well as the conduction state of the two diodes.
Table 2. STAT Output Pin Funtion
ENB1 ENB2 CONDITIONS STAT
Low Low Diode A Forward Bias,
Diode B Forward Bias
I
SNK
= 0μA
Diode A Forward Bias,
Diode B Reverse Bias
I
SNK
= 0μA
Diode A Reverse Bias,
Diode B Forward Bias
I
SNK
= 9μA
Diode A Reverse Bias,
Diode B Reverse Bias
I
SNK
= 9μA
Low High Diode A Forward Bias,
Diode B Disabled
I
SNK
= 0μA
Diode A Reverse Bias,
Diode B Disabled
I
SNK
= 9μA
High Low Diode A Disabled,
Diode B Forward Bias
I
SNK
= 0μA
Diode A Disabled
Diode B Reverse Bias
I
SNK
= 9μA
High High Diode A Disabled,
Diode B Disabled
I
SNK
= 9μA
Introduction
The LTC4413 is intended for power control applications
that include low loss diode ORing, fully automatic
switchover from a primary to an auxiliary source of power,
microcontroller controlled switchover from a primary to
an auxiliary source of power, load sharing between two or
more batteries, charging of multiple batteries from a single
charger and high side power switching. The LTC4413 is
optimized for low quiescent power consumption at the
expense of transient response. For more demanding slew
rate or load transient applications, the pin compatible
LTC4413-1 is recommended.
Dual Battery Load Sharing with Automatic Switchover
to a Wall Adapter
An application circuit for dual battery load sharing with
automatic switchover of load from batteries to a wall adapter
is shown in Figure 3. When the wall adapter is not present,
whichever battery that has the higher voltage provides the
load current until it has discharged to the voltage of the
other battery. The load is then shared between the two
OPERATION