SMPS a converter - help!

[formula 22]

Hi
I'm working on this SMPS project under the schematic Figure 1.
The only problem that I can not resolve is the ferrite transformer. It has a toroidal ferrite as the datascheet-in (tn322913).
Now I ask you for help, how to get to the exit 2x35V/2x5A. How winding wires should have a primary, secondary and how much and what section, at the same operating frequency to be 40kHz.
Thanks

[darkfenriz]

dB= V*T/ 2*N1*Ae

V=2*12V (for push pull)
T=25us=25E-6s
N1 (primary turns)=?
Ae=76.5 mm^2= 76.5E-6 m^2 (from datasheet)

dB should be chosen for acceptable core losses, for 40kHz I would recommend around 150mT for safe and relatively cool core operation. Consult core losses table in datasheet.

So, calculate N1 first:
N1=V*T/2*Ae*dB=
= 24*25E-6/2*76.5E-6*0.15 = 26 turns (each primary)

Turns ratio is the same as the voltages ratio between primary and secondary, so N2=26 turns * 35V/24V = 38 turns

[formula 22]

Originally Posted by darkfenriz

dB= V*T/ 2*N1*Ae

V=2*12V (for push pull)
T=25us=25E-6s
N1 (primary turns)=?
Ae=76.5 mm^2= 76.5E-6 m^2 (from datasheet)

dB should be chosen for acceptable core losses, for 40kHz I would recommend around 150mT for safe and relatively cool core operation. Consult core losses table in datasheet.

So, calculate N1 first:
N1=V*T/2*Ae*dB=
= 24*25E-6/2*76.5E-6*0.15 = 26 turns (each primary)

Turns ratio is the same as the voltages ratio between primary and secondary, so N2=26 turns * 35V/24V = 38 turns

Thank you, Mr.darkfenriz!