TPS1HC30-Q1
ZHCSP75A –JULY 2022 –REVISED DECEMBER 2022
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assured to protect against short-circuit events regardless of the state of the ILIM pins and with up to 28-V supply
at 125°C.
The following figure shows the behavior of the TPS1HC30-Q1 when the device is enabled into a short circuit.
Current (A)
ICL_ENPS
ICL
Thermal Shutdown
tRETRY
Time (s)
图8-12. Enable into Short-Circuit Behavior (LATCH=0)
Due to the low impedance path, the output current rapidly increases until it hits the current limit threshold. Due to
the response time of the current limiting circuit, the measured maximum current can temporarily exceed the ICL
value defined as ICL_ENPS, however, it settles to the current limit regulation value.
In this state, high power is dissipated in the FET, so eventually the internal thermal protection temperature for the
FET is reached and the device safely shuts down. Then, if LATCH pin is low, the part waits tRETRY amount of
time and turns back on.
图 8-13 shows the behavior of the TPS1HC30-Q1 when a short circuit occurs when the device is in the on-state
and already outputting current. When the internal pass FET is fully enabled, the current clamping settling time is
slower so to ensure overshoot is limited the device implements a fast-trip level at a level IOVCR. When this fast-
trip threshold is hit, the device immediately shuts off for a short period of time before quickly re-enabling and
clamping the current to ICL level after a brief transient overshoot to the higher peak current (ICL_ENPS) level. The
device then keeps the current clamped at the regulation current limit until the thermal shutdown temperature is
hit and the device safely shuts off.
Current (A)
IOVCR
ICL_ENPS
ICL
Thermal Shutdown
tRETRY
INOM
Time (s)
图8-13. On-State Short-Circuit Behavior
Overload Behavior shows the behavior of the TPS1HC30-Q1 when there is a small change in impedance that
sends the load current above the ICL threshold. The current rises to ICL_LINPK above the regulation level. Then
the current limit regulation loop kicks in and the current drops to the ICL value.
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