AN4165 datasheet(23/37 Pages) STMICROELECTRONICS

Part #	AN4165

Description	This document describes a 12 V - 1 A power supply set in non-isolated flyback topology

PDF	37 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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AN4165

Functional check

Doc ID 023661 Rev 1

23/37

shorting the low-side resistor of the output voltage divider, R4 = R4a + R4b. The same

behavior can be caused by opening the high-side resistor, R3.

The protection acts in auto-restart mode with tRESTART = 1 s (Figure 31). When the fault is

removed, normal operation is restored after the last tRESTART interval has been completed

(

Figure 33).

Figure 30.

Feedback loop failure protection:

tripping

Figure 31.

Feedback loop failure protection:

steady-state

AM11578v1

Normal

operation

< tOVL

Fault is applied here

VDD reaches VDDCLAMP

AM11579v1

tRESTART

Figure 32.

Feedback loop failure protection:

steady-state, zoom

Figure 33.

Feedback loop failure removal:

converter restart

AM11580v1

< tOVL

AM11581v1

tRESTART

Fault is removed here

Normal

operation

AN4165 Datasheet(PDF) 23 Page - STMicroelectronics