AN1376 datasheet(12/35 Pages) STMICROELECTRONICS

Part #	AN1376

Description	25W QUASI-RESONANT FLYBACK CONVERTER FOR

PDF	35 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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12 / 35 page

AN1376 APPLICATION NOTE

12/35

DYNAMIC LOAD TESTS

Regulated Output

Figure 9.

The pictures show the output voltage regulation against a dynamic load variation of the feed

backed voltage, at the nominal input voltage values. As shown in the left pictures the response

after the connector is not very good from the peak point of view, even if the response is quite

fast. Making the same measure before the filter inductor (L4), at the feed back divider connec-

tion points, the response is much better (

≈2.2 %). This means that the filter inductor heavily

Load condition:

+5V, +7V, +12V, +30V:

FULL LOAD

+3,3V:

LOAD 50 %

÷100%, 70Hz

@115 VAC - 50Hz

@220 VAC - 50Hz

CH3:

+3V3 Vout at test points

CH1:

+30 Vout

CH4:

+3V3 Iout

CH2:

+12 Vout

R1:

+3V3 Vout before L4

CH3:

+7 Vout

CH4:

+3V3 Iout

AN1376 Datasheet(PDF) 12 Page - STMicroelectronics