L6565

14/17

Figure 24. Primary Feedback loop configurations

a)

Vcc

-

+

GND

L6565

E/A

INV

2.5V

COMP

to VFF

block

8

2

1

6

Vcc

-

+

GND

L6565

E/A

INV

2.5V

COMP

to VFF

block

8

2

1

6

b)

Figure 25. Protection against secondary

feedback disconnection by primary

regulation take-over

Figure 26. Leading edge blanking circuit for

enhanced primary regulation

Figure 27. Remote ON/OFF control

Figure 28. Low-consumption start-up circuit

8

Vcc

L6565

INV

1

15 V

2.2 k

Ω

COMP

2

Vcc

GND

L6565

1N4148

BC327

2.7 k

Ω

470 pF

L6565

ZCD

ON

OFF

BC337

5

8

6

L6565

Vac

R

1N4148

+Vin

Vcc

GND

1N4148

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).