Main characteristics and circuit description

AN2755

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At startup the L6562A is powered by the Vcc capacitor (C12) that is charged via the

resistors R3 and R4. Then the L4 secondary winding (pins 8-11) and the charge pump

circuit (R5, C10, D5 and D4) generate the Vcc voltage powering the L6562A during normal

operation.

The divider R32, R33 and R34 provides the L6562A multiplier with the information of the

instantaneous voltage that is used to modulate the boost current. The divider R9, R10, R11,

R12 & 13 is dedicated to sense the output. The Line-Modulated FOT is obtained by the

timing generator components D6, C15, R15, C16, R16, R31, Q3.

The board is equipped with an input EMI filter designed for a 2-wire input mains plug. It is

composed of two stages, a common mode pi-filter connected at the input (C1, L1, C2, C3)

and a differential mode pi-filter after the input bridge (C4, L3, C5). It also offers the

possibility to easily connect a downstream converter.

Figure 2.

EVL6562A-400W demonstration board electrical schematic

 

5

8

7

6

4

3

2

1

ZCD

CS

MULT

COMP

INV

L65 62A

VCC

GD

GND

R102

0R0

+400Vo ut

R19

1K0

C20

330 pF

L1

CM- 1.5mH-5A

L3

DM-51uH- 6A

C15

68pF

C16

120p F

R22

0R47-1W

R15

1k8

C11

470nF/50V

C12

100uF/50V

R1 6

30k

1

2

J1

Q2

STP12NM50FP

C1

470nF-X2

D6

LL41 48

R20

0R47-1 W

D5

BZX85-C18

R23

0R4 7-1W

R1

1M5

D1

1N54 06

1

2

3

4

5

J2

D3

STTH8R06

F1

8A/250V

R3

100K

C21

10nF

R17

6R8

R34

10k

R18

6R8

Q3

BC857C

R33

620k

D7

LL41 48

C4

470n F-6 30V

R32

620k

D8

LL4148

R2

NTC 2R5-S237

T

PQ40- 500uH

Q1

STP12NM50FP

R4

100K

R31

3k

R21

0R4 7-1W

+

-

~

~

D2

D15XB60

R5

47R

C5

470nF-63 0V

R12

47K

R13

12k

R11

510k

R10

510k

R35

3R9

R36

3R9

R9

510k

C2

470nF

R14

47k

C3

680n F-X2

C6

470nF-630V

C14

2.2uF

C13

22 0nF

D4

LL4 148

C7

330uF-450 V

C10

22N

+400Vdc

1-2

+400Vdc

+400Vdc

5-6

811

RTN

NC

RTN

+400Vdc

90 - 265Vac

R101

0R0