AN1376 APPLICATION NOTE

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15 SWITCH ON AND TURN OFF IN SHORT CIRCUIT CONDITION

■

FULL LOAD

■

SHORT ON 3V3 BY ACTIVE LOAD

The following pictures describe the SMPS behaviour during the start-up phase with an output

voltage shorted. As clearly visible the circuit starts correctly then it works in hic-cup mode pro-

tecting itself. The start-up phase is clean in all conditions, without showing any dangerous tran-

sition for the SMPS circuitry.

Figure 24. START

Figure 25. TURN-OFF

Even at turn off in short circuit the SMPS functionalities are good, protecting properly the cir-

cuit. No any abnormal transition or level has been observed during the tests.

CH1:

CH1:

CH2:

CH2:

CH3:

+3V3 Vout

CH3:

+3V3 Vout