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SMPS topology selection

HIMANSHU SHARMA
Prodigy 80 points
Other Parts Discussed in Thread: UCC28C45

Hi all,

I am not able to be clear about the selection of SMPS topology and corresponding controller IC for my application. The requirements for my application are:

1.) Isolation required

2.) Input voltage range - 300V to 800V

3.) Power required - 150W

4.) No of output - 24V/6A and ±15V/100mA

5.) Efficiency - not to critical (as SMPS is used for supply of other larger power rated circuits)

6.) Cost and assembly - critical (as required in large number)

7.) Radiation issues - critical (if we opt for fixed frequency operation)

8.) Size - not critical

Please give me some suggestion or source to be clear about it.

Thanks,

HS

  • 0
    TI__Guru 73825 points

    Hi,

    As your application has three outputs, it looks the flyback topology should be used. If efficiency is not a critical design target, R-C-D snubber should be ok to use. So UCC28C4x such as UCC28C45 can be used. 

  • 0 in reply to Hong Huang
    Prodigy 80 points

    Hi,

    Thanks for your reply. Can I use quasi-resonant mode for this power rating. Or else, in case of fixed frequency operation, is there any limitation for frequency for this output requirement. Is there any application note available from TI which I can refer?

  • 0 in reply to HIMANSHU SHARMA
    Prodigy 80 points

    In addition to that, in case I am ready to use external converter for ±15V/100mA from 24V output (i.e. removing the requirement of multiple outputs), is it still the flyback which is best suited for rest of my requirement?

  • 0 in reply to HIMANSHU SHARMA
    TI__Guru 73825 points

    Hi,

    Based on your first list, you want to have a fixed switching frequency so QR cannot be used as QR needs frequency variation.

    The frequency depends on your applications. Your input voltage is high so lower frequency can be used for less power losses. You would have to decide frequency you want to use. From your list, it is not clear what frequency is good to your design. UCC28C4x can do 5kHz to 1000kHz.

    If you have else where to obtain 15V, then it is better to do this way. But your 150W converter may still stay on flyback to save an output inductor. You can do forward if you are ok to have an output inductor. UCC28C4x can be used for flyback or forward.