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UCC2897A: Detailed Comparison of UCC2897 Vs LM5026

Thirupathi Aluka
Prodigy 40 points
Part Number: UCC2897A
Other Parts Discussed in Thread: LM5026

Hi E2E Team,

I am working on one AC- DC power supply development which has the requirement of AC I/P range is from 90-130VAC and O/P of 5V/50W.

we have a high efficiency (>90%) requirement, So i went with active clamp forward converter topology with secondary synchronous rectification.

For this ACF topologies i am looking for discrete PWM Controller which will fulfill my above requirements.

I came across couple of PWM Controller's in TI and shortlisted two of them are LM5026 and UCC2897A.

May i have the detailed comparison of these LM5026 and UCC2897A PWM controllers. 

And also i request you to kindly suggest me which PWM controller will good fit or satisfy the above mentioned input and output requirements with technical justification.

Awaiting for your response.

Thank you,

Best regards,

Thirupathi Aluka

  • 0
    TI__Guru 53925 points

    Hi,

    LM5026 and UCC2897A are both peak current mode controllers. You can use either of them. I recommend using UCC2897A mainly due to more experience and knowledge have been accumulated due to UCC2897A developed much earlier than LM5026. 

    If you need to have delayed hiccup OCP, then you may go with LM5026. Otherwise, you should consider UCC2897A as your first option.

    Safety is separated from a PWM controller in this case which you need to design externally. 

  • 0
    Prodigy 40 points

    Hi Huang,

    Many thanks for your reply.

    I have understood the main difference between these two PWM controllers.

    but, with respect to safety, can you please little more elaborate on what type of safety you mentioned from PWM controller point of view which require external design? Like application (automotive/aerospace/dense/other industrial) specific safety or some internal protection features (OCP/OVP/OTP) of power supply. can you please help me in understanding this?

    and as i have mentioned my input type is AC and ratings are 90-130VAC, Is it ok to choose UCC2897A PWM controller which has the feature of only Low side clamping?

    i request you to share if you have any reference/application note on difference between high side clamping and low side clamping and there to choose the PWM controller.

    and from your experience what is maximum efficiency we can achieve with respect to mentioned input and output specification using UCC2897A, i know there are multiple things/design parameters will contribute in achieving the efficiency. But i would like to know if there is any reference design w.r.t my requirements (reference design near to my requirements also ok) which gives efficiency >90%.  

    Awaiting for your reply,

    Thank you,

    Best regards,

    Thirupathi Aluka

  • 0 in reply to Thirupathi Aluka
    TI__Guru 53925 points

    Hi,

    Low side clamping is based on P-channel MOSFET, as long as you can find proper P-channel MOSFET, then it is ok.

    for 90Vac to 130Vac, it looks ok you can use either high-side or low side. Usually P-channel MOSFET is bit more expensive while high-side clamping needs a high side driver such as a gate driver transformer or IC.

    This below link app note compares the low side and high side clamping.

    Active Clamp Transformer Reset: High Side or Low Side?

    There is a list of reference designs at this link:

    Search results - TI.com

    Also, this link has many design notes and application notes, simulation models, design sheet, on-line design.

    You can also contact your local TI support to see if they can help to request a reference design.

  • 0 in reply to Hong Huang
    Prodigy 40 points

    Hi Haung,

    thanks for your fast reply, greatly appreciated.

    can you also please provide your answer on safety related questions on PWM controller?

    Thank you,

    Best regards,

    Thirupathi. A 

  • 0 in reply to Thirupathi Aluka
    TI__Guru 53925 points

    Hi,

    UCC2897A is an industrial device. It has protection of OCP OTP OVP - please read its datasheet for each.