L6565
Figure 24. Primary Feedback loop configurations
Vcc
Vcc
8
COMP
COMP
8
2
1
2
1
H
H
R
R
R
R
-
-
to VFF
block
to VFF
block
INV
INV
E/A
E/A
+
+
L
L
2.5V
2.5V
GND
GND
6
6
L6565
L6565
a)
b)
Figure 25. Protection against secondary
Figure 27. Remote ON/OFF control
feedback disconnection by primary
regulation take-over
L6565
5
Vcc
15 V
ZCD
8
1
INV
OFF
L6565
BC337
2
ON
COMP
2.2 kΩ
Figure 28. Low-consumption start-up circuit
Figure 26. Leading edge blanking circuit for
enhanced primary regulation
+Vin
Vac
BC327 1N4148
R
CSTART
1N4148
Vcc
Vcc
CSUPPLY
8
470 pF
L6565
1N4148
L6565
Ω
2.7 k
6
GND
GND
RELATED DOCUMENTATION
[1] "L6565, QUASI-RESONANT CONTROLLER” (AN1326)
[2] “25W QUASI-RESONANT FLYBACK CONVERTER FOR SET-TOP BOX APPLICATIONS USING THE
L6565” (AN1376)
[3] “EVAL6565N, 30W AC-DC ADAPTER WITH THE L6565 QUASI-RESONANT PWM CONTROLLER”
(AN1439).
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STMICROELECTRONICS [ ST ]
