myrra 74030 top 244 yn 24 V 1A

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hi everybody,
I want to make a power supply 24V 1A using this transformateur myrra 74030 with topswitch 244 Yn;
I already made one with this transformer and this 244 yn for 12 V and 2A,this is represneted in this fille so what i need to change with the values,
thank you

첨부 파일Size
myrra.pdf158.26 KB
top.pdf126.96 KB

Hi hicham,
You may use our PI expertonline tool for you to optimize your design. The tool doesn't support topswitch gx family but you may use topswitch-hx family for computations purposes. Topswitch datasheet is also available in case you want to compare the changes between gx family and the hx family in the computations. (

thanks for response,but which parameters i need to compare to change top switch hx with top switch gx

Hi Hicham,
Are your component values exactly same as the ones shown in the reference schematic? If not then can you please share the actual schematic with us to know the component values and ratings?

Since this is a fixed transformer with the fixed inductance and number of turns, You can either use S1, S2 and S3 all in series or use S2 and S3 in series to get 24 V output. You need to adjust the feedback resistors values R6 and R8. You can validate your design in PI expert as suggested in previous reply by Jedidiah. The parameters you would need to input are input VAC range, Vo, Io, Input capacitor, feedback resistors, primary turns and then adjust the frequency to get the desired inductance matching with your transformer.


hi thanks for the response;
so about the value its for 12 V.
i apply your recommendation ; volatge,Io,Vo,spire number,frequency.
thats what i found i think this transformer is like my transformer

what do you think but for that i changed KP

p1.PNG36.6 KB
p2.PNG6.03 KB
p3.gif82.09 KB

Hi Myrra,
I apologize for the delayed response. I couldn't understand your question about the Kp. Are you asking if the Kp value which you have chosen is valid to be used? If you meant to ask something else then please clarify.