Datasheet

Thermal Shutdown Power Good (PWRGD)
TPS54617
SLVS880A – NOVEMBER 2008 – REVISED JANUARY 2009 ........................................................................................................................................... www.ti.com
The device uses the thermal shutdown to turn off the The power good circuit monitors for under voltage
power MOSFETs and disable the controller if the conditions on VSENSE. If the voltage on VSENSE is
junction temperature exceeds 150 ° C. The device is 10% below the reference voltage, the open-drain
released from shutdown automatically when the PWRGD output is pulled low. PWRGD is also pulled
junction temperature decreases to 10 ° C below the low if VIN is less than the UVLO threshold or SS/ENA
thermal shutdown trip point, and starts up under is low. When VIN ≥ UVLO threshold, SS/ENA ≥
control of the slow-start circuit. enable threshold, and VSENSE > 90% of V
ref
, the
open drain output of the PWRGD pin is high. A
Thermal shutdown provides protection when an
hysteresis voltage equal to 3% of V
ref
and a 35 µ s
overload condition is sustained for several
falling edge deglitch circuit prevent tripping of the
milliseconds. With a persistent fault condition, the
power good comparator due to high frequency noise.
device cycles continuously; starting up by control of
the soft-start circuit, heating up due to the fault
condition, and then shutting down upon reaching the
thermal shutdown trip point. This sequence repeats
until the fault condition is removed.
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