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UC28025: is this IC suitable for high frequency circuits

bhagyashree k
Prodigy 35 points
Part Number: UC28025
Other Parts Discussed in Thread: UC3526, UCC27714, UCC28951

Hi

our requirements

vin =370V dc

vout=1000V DC, 1A 

topology FULLBRIDGE converter

frequency 90khz with varying duty ratio 

application dc dc converter

CAN  WE USE THIS IC FOR OUR APPLICATION.PLEASE SUGGEST..

REGARDS

Bhagyashree

  • 0
    TI__Mastermind 24715 points

    Hi Bhagyashree,

    UC28025 is a legacy controller intended to drive a push-pull power stage. This controller has OUTA, OUTB where both outputs are GND referenced but the full-bridge you are proposing will need high-side gate drive that is level shifted with respect to GND. Have you seen the TI portfolio of phase-shifted full bridge PWM controllers? These controllers are available in wide variety of options including advanced green mode features, with or without SR control, automotive qual, enhanced performance qual.

    Regards,

    Steve M

  • 0 in reply to Steven Mappus1
    Prodigy 35 points

    Thank you for the response 

     can we use uc28025 PWM controller with ucc27714D  gate driver 

    we want to build full bridge converter topology 

    if any alternative ICs please suggest for full-bridge only

  • 0 in reply to Steven Mappus1
    Prodigy 35 points

    Dear sir 

    i have used uc3526 pwm controller with ucc27714d in the circuit 

    at transformer primary we getting pulsed dc waveform for 25khz we can see the dead time in the waveform 

    but when we go for high frequency 90khz waveform is not proper we cannot see pulsed dc without dead time there is ringing waveform 

    what might be the issue ?so i thought of trying with uc28025 pwm controller 

    can you please tell me the opinion

  • 0 in reply to bhagyashree k
    TI__Mastermind 24715 points

    Hi Bhagyashree

    Yes, you could control a full bridge power stage using UC3526 or UC28025 with two half-bridge drivers such as UCC27714. Both of the controllers you mentioned are fabricated on a bipolar IC process which is one of the limiting factor for achieving "high frequency" operation. I'm not sure how high you intend to go with your switching frequency but 90 kHz should be no problem for either of these controllers when they are configured properly. Also, UC3526 is voltage mode control (VMC) only while UC28025 is current mode control (CMC) by default but can be configured for VMC. A full-bridge design with either of these controllers will result in a traditional hard-switched duty cycle controlled power converter. Tried and true but not the best EMI or efficiency compared to a phase-shifted full-bridge (PSFB).

    You must consider the entirety of your system requirements but my recommendation is UCC28951 Phase-Shifted Full-Bridge Controller. Phase shift control has many protection, safety, control and efficiency advantages over PWM control. Also, I believe you will find more app notes, models, reference designs and EVMs that more closely suits your design specs. Here is the TI portfolio of PWM full-bridge controllers vs phase-shift, full-bridge controllers.

    Thanks for considering TI and for connecting through E2E. 

    Regards,

    Steve M