Datasheet

OUT IN OUT
V V RON I= - ´
RLIM
LIM
201 k
R
I
W
=
RFLT
FAULT
200 k
R
I
W
=
TPS2590
SLUS960G –JULY 2009–REVISED JANUARY 2014 www.ti.com
FLT: Open-drain output that pulls low on any condition that causes the output to open. These conditions are
either an overload with a fault time-out, or a thermal shutdown. FLT becomes operational before UV, when IN is
greater than 1 V. I
FAULT
may not be set below 1 A to maintain the Fault Current-Limit threshold accuracy listed in
Electrical Characteristics. FLT will pulse low momentarily prior to the onset of OUT ramp up during IN or EN
based start-up.
GND: This is the most negative voltage in the circuit and is used as reference for all voltage measurements
unless otherwise specified.
IFLT: A resistor connected from this pin to ground sets the fault current threshold (I
FAULT
). Currents between the
fault current threshold and the current-limit are permitted to flow unimpeded for the period set by the fault timer
programmed on CT. This permits loads to draw momentary surges while maintaining the protection provided by a
lower average-current-limit.
The fault timer described in the CT section starts when I
OUT
exceeds I
FAULT
. The fault current resistor is set using
Equation 3 where I
FAULT
is in Amperes and R
RFLT
is in Ohms.
(3)
ILIM: A resistor connected from this pin to ground sets I
LIM
. The TPS2590 device limits current to I
LIM
. If the
current doesn’t drop below the I
FAULT
level before the timer times out then the output will be shut off. R
RLIM
is set
by Equation 4:
(4)
I
LIM
must be set sufficiently larger than I
FAULT
to ensure that l
LIM
could never be less than I
FAULT
, even after taking
tolerances into account.
EN: When this pin is pulled low, the IC is enabled. The input threshold is hysteretic, allowing the user to program
a startup delay with an external RC circuit. EN is pulled to IN with a 10 MΩ resistor and to GND with a 16.8 MΩ
resistor. Because high impedance pullup/down resistors are used to reduce current draw, any external FET
controlling this pin should be low leakage.
IN: Input voltage to the TPS2590 device. The recommended operating voltage range is 3 V to 20 V. All IN pins
should be connected together and to the power source.
OUT: Output connection for the TPS2590 device. V
OUT
in the ON condition considering the ON resistance of the
internal MOSFET, RON is shown in Equation 5.
(5)
All OUT pins should be connected together and to the load.
RTRY: When pulled low the TPS2590 device attempts to restart after a fault. If left floating or pulled high the
TPS2590 device latches off after a fault. This pin is internally clamped at 3 V and is pulled to the internal 3-V
supply by a diode in series with a 100-kΩ resistor.
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