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AN1673 APPLICATION NOTE

APPENDIX A.

A practical way to handle the resonant components is to adopt the normalized voltage and current.

The minimum operative frequency has been set at 65kHz. This frequency can be considered a good com-

promise for holding the transformer's magnetic set low size and to avoid the high frequency problems (e.g.

skin effect, switching losses and so on).

Let us fix the normalized out put voltage M = 0.98

Assume normalized operating current as J = 0.2

The resonant Zo can be calculated as

– The resonant capacitor will be:

– The resonant Inductance

REFERENCES:

[1] A Comparison of Half-Bridge Resonant Converter Topologies.

ROBERT L. STEIGERWALD,

IEEE Transactions on Power Electronics. April 1988.

[2] Small signal ac equivalent circuit modeling of the series resonant converter.

Arthur F. Witulski ; Robert W. Erickson IEEE Power Electronics Specialist Conference 1987

[3] Analysis and Design of LCL-Type Series Resonant Converter.

By Ashoka K.S. Bhat,

IEEE Transactions on Industrial Electronics. February 1994.

[4] Design Optimization for an LCL-Type Series Resonant Converter

M. B. Borage, S.R. Tiwari and S. Kotaiah; Power Supplies Division - Center for Advanced Technology

Indore, India

www.powerpulse.net/powerpulse/archive/aa_030501a1.stm

[5] Application note: AN966; AN1300

STMicroelectronics

M

V

o

n

⋅

V

in max

()

2

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

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

≅











J

I

o

R

o

⋅

n

V

in max

()

2

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

⋅

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

≅











Lr

Cr

------

Z

o

V

in

2

--------





2

JM

⋅⋅

V

o

I

o

⋅

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

=

Cr

1

Z

o

ω

⋅

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

Cr

1

110 2

π 65 10

3

⋅⋅

⋅

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

20nF

≅≅

≅

Lr

Z

o

ω

------

Lr

110

2

π 65 10

3

⋅⋅

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

295

µH

≅≅

≅