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Isolated flyback AC to DC converter

bhargav goud
Prodigy 160 points
Other Parts Discussed in Thread: UCC28704, UCC28742, UCC28C43-EP, UCC28051, PMP9730, UCC28740, UCC28056

Hello

I am currently working on a isolated flyback  AC to DC converter design and looking for a flyback controller

Below are the basic requirements :

input Voltage: 115VAC (nominal)
output Voltage: 18V (nominal)
Output current : 1.2 A (nominal)
Operating temperature : -40 to 150C
Please suggest some Flyback controller,also is power factor correction required?

Thank You!

  • 0
    TI__Expert 8210 points

    Bhargav

    Generally at the power level you are designing at we do not see power factor correction (PFC) as a requirement.  Based on your question I am assuming that you do not need PFC.  If this is incorrect and you do need PFC please let me know.

    Based on your specification we recommend a flyback converter.  Either UCC28704 with primary side regulation (PSR) or UCC28742 with secondary side regulation (SSR) would be our first recommendation.  Please note that the recommended temperature range is only up to 125C and the abs max is 150C, so if this is unacceptable then you will need to use different devices.

    If you need to use a device with a recommended operating range up to 150C, then our current mode PWM controller UCC28C43-EP configured as a flyback will work best.  This EP variant of this device supports a wider temperature range that meets your requirement.

    Best Regards,

    Eric

  • 0 in reply to Eric Faraci
    Prodigy 160 points

    Hello Eric,

    Thank you very much for your quick reply.

    Regarding the power factor correction, my doubt was, will the power factor be reasonably good when any of the Flyback controllers is used in general.

    I'm what range can we expect the power factor to be , with the controllers you have suggested?

    If the power factor goes below 0.75, could you please suggest some PFC methods which can be implemented with the suggested flyback controllers.

    Thank you!

  • 0 in reply to bhargav goud
    TI__Expert 8210 points

    Bhargav

    Without any power factor correction, a flyback converter will not achieve power factor above 0.75.  There are a few ways you can improve it though

    • Passive power factor correction - this article summarizes how you can achieve PFC with inductor and/or capacitor https://www.nuvation.com/resources/article/power-supply-design-basics-passive-pfc-design
    • PFC Flyback - you can convert a PFC controller to work in a flyback topology.  PMP9730 is an example of a PFC flyback with our TM PFC controller UCC28051
    • PFC Boost followed by flyback - to get the highest efficiency best performance a PFC boost with UCC28056 followed by a flyback such as UCC28740 will give high performance

    Best Regards,

    Eric

  • 0 in reply to Eric Faraci
    Prodigy 160 points

    Eric,

    Thank you very much for your inputs.

    Regards

    Bhargav