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TPS40210 - Flyback design equations

Atul Bhakay
Genius 3205 points
Other Parts Discussed in Thread: TPS40210

Hi,

I want to design a power supply, using TPS40210,  with the following specs-

Input = 19VDC to 90VDC

Output = 5V / 0.6 Amps

Topology = Flyback

Kindly suggest the transformer design details for this requirement

 I have posted this query about 4 days back, but there is still no reply  !!!!!!!!!!!!!!!!!!!!!

Regards

Atul Bhakay

  • 0
    Intellectual 930 points

    To give you an answer the knowledge of the switching frequency you want to implement is mandatory...

    And more...

    Do you need insulation or not?

    Bye

    Paolo

  • 0 in reply to Paolo Reggio
    Genius 3205 points

    Hi,

    The switching freq that I want to operate TPS40210 is 44KHz . Yes I want an isolated , flyback design

    Can you help me with the flyback design equations. There are many designs using the TPS40210 in flyback mode , in the power designs library. Then why cannot somebody help me with the flyback design equations for this device ?

    Regards

    Atul Bhakay

  • 0 in reply to Atul Bhakay
    Intellectual 930 points

    With the given specification you will have the following results:

    Primary side inductance: 120uH

    Peak current: 1.25A

    RMS current: 0.45A

    Secondary side RMS current: 1.1A

    Turn ratio Np/Ns: 2.8

    This could be enough to let you wire the coupled inductances...
    Be careful!

    You have to use gapped cores!

    Have a nice day

    Paolo

  • 0 in reply to Paolo Reggio
    Genius 3205 points

    Thanks, Paolo

    Did you use the power stage design tool OR did you arrive at these values by discrete equations ?

    I would still like to have the discrete equations, so that I do not have to depend on somebody (and in the process loose 4 to 5 days) to design with TPS40210 !!

    Regards

    Atul Bhakay

  • 0 in reply to Atul Bhakay
    Intellectual 930 points

    Hello.

    Usually I use both...

    First I use discrete equations, then I check using power design tools and simulations, expecially to design the feedback loop...

    I've designed excel sheets in which it's enough to put input and output data and they make all the calculations, also if each time I prefer to make calculations with pencil and paper in order to avoid mistakes...

    It's really difficult to post equations here, with this kind of editor, but I think you could find them on the website...

    In my honest opinion, you could check to push up switching frequency...

    Required inductance value to work in DCM will be lower and you can save space using smaller magnetic cores with lower turn numbers...