AN1606 APPLICATION NOTE

12/18

m)

were f is the input frequency.

Imposing <10Vac the peak of voltage variation over 400Vo, the Co value will results >318

µF; the commercial

value is 330

µF

Power Devices.

The selection of the power devices is dependent upon the topology and the size of the application.

Operating in continuous current mode, fast reverse recovery diodes are needed.

The TURBOSWITCH "STM family", in the 600V voltage range, offers a very good solution for the two boost

diodes, the STTH8R06FP has been chosen.

The insulated TO-220 package makes it easy to assemble the parts on a heat sinke.

Concerning the Powermos requirements, a 500V blocking voltage (Bvdss) is needed, for this application.

The chip selection is more complex. To find the best solution, it must be considered all the parameters that affect

the power dissipation and to compare the results in terms of a cost to benefit ratio. The devices used in the 800W

application (2+2), are the type STY34NB50F.

The four Powermos are efficiently driven without any additional buffer, thanks to the smart characteristics of the

integrated driver.

Figure 10. 800W SCHEMATHIC DIAGRAM.

Co

Po

2

π 2f ∆fo Vo

⋅

⋅⋅ ⋅ ⋅

---------------------------------------------------

=

L4981A/B

4

1

20

8 2

11

6

18

17

12

14

3

9

5

15

16

7

10

19

F

1

C

1

L

1

D

5

D

6

R

9

R

10

C

3

NTC

C

4

R

11

R

12

R

14

R

15

C

5

R

17

C

6

C

7

R

18

C

8

R

19

C

10

R

21

C

12

13

L

2a

L

2b

L

2c

DETAIL for L2

L

2b

L

2c

L

2a

Vcc

Vcc

L

3

Vcc

D

R

1

Dz

1

C

2

R

2

D

7

D

8

R

3

R

4

D

9

D

10

R

5

R

6

Q

1

Q

2

Q

3

Q

4

R

7

D

11

D

12

R

8

D

13

R

13

R

16

R

20

R

22

C

13

R

23

C

14

C

15

C

16

R

24

R

25

R

26

R

27

R

28

R

29

R

30

R

31

R

32

R

33

Input

C

11