IPS161HF datasheet(11/27 Pages) STMICROELECTRONICS

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Protection and diagnostic

The IC integrates several protections to ease the design of a robust application.

6.1

Undervoltage lock-out

The device turns off if the supply voltage falls below the turn-off threshold (VUV(off)). Normal operation restarts

after VCC exceeds the turn-on threshold (VUV(on)). Turn-on and turn-off thresholds are defined in Table 4. Supply.

6.2

Overtemperature

The output stage turns off when its internal junction temperature (TJ) exceeds the shutdown threshold TJSD.

Normal operation restarts when TJ comes back below the reset threshold (TJSD - TJHYST), see Table 8. Protection

and diagnostic. The internal fault signal is set when the channel is off due to thermal protection and it is reset

when the junction triggers the reset threshold. This same behavior is signaled on the DIAG pin.

6.3

Cut-off

The IC can limit the output current at the power stage by its embedded output current limitation circuit.

This circuit continuously monitor the output current and, when load is increasing, at the triggering of its activation

threshold (Ipk) it starts limiting to ILIM limitation level: while current limitation is active the IC enters an high

dissipation status.

The IPS160HF implements the cut-off feature which limits the duration of the current limitation condition.

The duration of the current limitation condition (Tcoff) can be set by a capacitor (CCoD) placed between CoD and

GND pins. The design rule for CCoD is:

tcoff[us] ±35% = 50 x Ccod[nF]

The ±35% drift is guaranteed in the range of 10 nF < Ccod < 100 nF; lower capacitance than 10 nF can be used.

If ILIM threshold is triggered, the output stage remains in the current limitation condition (IOUT = ILIM) no longer

than tCOFF. If tCOFF elapses, the output stage turns off and restarts after the tRES restart time.

Thermal shutdown protection has higher priority than cut-off:

•

IC is forced off if TJSD is triggered before tCOFF elapses

•

if TJSD is triggered, IC is maintained off even after the tRES has elapsed and until the TJ falls below TJSD-

TJHYST

IPS160HF, IPS161HF

Protection and diagnostic

DS13271 - Rev 2

page 11/27

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