AN1517 datasheet(21/30 Pages) STMICROELECTRONICS

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DocID8827 Rev 3

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AN1517

Application information

Figure 14. Short-circuit current VIN = 25 V

Figure 15. Short-circuit current VIN = 30 V

In Figure 14 and Figure 15, for example, it can be observed that when the input voltage

increases for a given component list, the current peak increases also. The current limit is

immediately triggered but the current peak increases until the current ripple during the TOFF

is equal to the current ripple during the TON.

5.5

Application circuit

Figure 16 shows the demonstration board application circuit for the device in the SMD

version, where the input supply voltage, VCC, can range from 4.4 V to 25 V due to the rated

voltage of the input capacitor and the output voltage is adjustable from 1.235 V to VCC.

Figure 16. Demonstration board application circuit

Vout

LIMIT

Vout

LIMIT

L5972D

μF

25V

CERAMIC

100

μF

10V

VOUT=3.3V

VIN = 4.4V to 25V

5.6K

3.3K

4.7K

22nF

220pF

L1 33

μH

STPS2L25U

COMP

VCC

OUT

GND

AM00027v1

L5972D

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