Datasheet

3
SD CT
t 885.7 10 C= ´ ´
T
FAULT
C
CT
3
40 10
=
´
4
2
3
8
12
11
10
9
15 14 13
1
5 6 7
TPS2590
16
GND
CT
IFLT
ILIM
IN
EN
OUT
IN
IN
IN
OUT
OUT
FLT
GND GND
RTRY
TPS2590
www.ti.com SLUS960F –JULY 2009–REVISED MAY 2013
TPS2590 PINOUT
TERMINAL FUNCTIONS
FUNCTION TPS2590 DESCRIPTION
EN 16 Device is enabled when this pin is pulled low.
IN 1-4 Power In and control supply voltage.
6 If low, the TPS2590 will attempt to restart after an overcurrent fault. If floating (high) the device will latch
RTRY
off after an overcurrent fault and will not attempt to restart until EN or Vin is cycled off and on.
ILIM 7 A resistor to ground sets the current limit level.
IFLT 8 A resistor to ground sets the fault current level.
CT 9 A capacitor to ground sets the fault time.
GND 5, 13, 14 GND
OUT 10, 11, 12 Output to the load.
FLT 15 Fault low indicated the fault time has expired and the FET is switched off.
PIN DESCRIPTION
CT: Connect a capacitor from CT to GND to set the fault time. The fault timer starts when I
OUT
exceeds I
FAULT
or
when SOA protection mode is active, charging the capacitor with 35 μA from GND towards an upper threshold of
1.4V. If the capacitor reaches the upper threshold, the internal pass MOSFET is turned off. If RTRY > 2.0V, the
MOSFET will remain off until EN is cycled. If RTRY ≤ 0.8V, the capacitor will discharge at 1.4μA to 0.16V and
then re-enable the pass MOSFET. If the upper threshold is not crossed, the capacitor will discharge at 40μA to
0.16V and then to 0V at 1.4μA. When the device is disabled, CT is pulled to GND through a 50kΩ resistor.
The timer period must be chosen long enough to allow the external load capacitance to charge. The nominal (not
including component tolerances) fault timer period is selected using Equation 1 where T
FAULT
is the minimum
timer period in seconds and C
CT
is in Farads.
(1)
If RTRY < 0.8V, the second and subsequent retry timer periods will be slightly shorter than the first retry period.
CT nominal (not including component tolerances) discharge time, t
SD
from 1.4V to 0.16V is shown in Equation 2,
where C
CT
is in Farads and t
SD
is in seconds.
(2)
The nominal ratio of on-to-off times represents about a 3.7% duty cycle when a hard fault is present on the
output.
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