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Isolated gate driver IC UCC21250

Ramesh Palanisamy
Intellectual 620 points
Other Parts Discussed in Thread: UCC21520

Hello TI experts,

I am interested to use the Isolated gate driver IC UCC21250 for one of my application.
I need to ensure few points mentioned below before selecting UCC21250

1, What is the type of isolation(galvanic/opto/capacitive)inbuilt in UCC21250 ?


2, Is the gate driver IC UCC21250 perfectly suited for converter specification mentioned below.
Vindc: 48V,Voutdc : 400V ,switching frequency: 100 kHz,output power : 3000W,
topology : Phase shifted full bridge with LC output filter


3,I am facing noise related problems with my present gate driver IC where the switching frequency noises are coupled back to
controller PWM pulses.Will UCC21250 have similar issues?


4, The datasheet mentioned in the website provides limited information.Is this product available in market?


5, kindly share application notes,schematics if available,since i couldn't locate from TI site.

regards,
Ramesh.P

  • 0
    TI__Mastermind 31580 points
    Hi Ramesh,

    I have asked one of the driver team application engineers to answer this question, you should see a reply soon.

    Regards

    Peter
  • 0 in reply to Peter Meaney
    TI__Intellectual 2061 points
    Peter, Thanks very much.

    Ramesh, Thanks very much for your interest. and here is your reply.

    1, What is the type of isolation(galvanic/opto/capacitive)inbuilt in UCC21250 ?
    It is capacitive isolation.

    2, Is the gate driver IC UCC21250 perfectly suited for converter specification mentioned below.
    Vindc: 48V,Voutdc : 400V ,switching frequency: 100 kHz,output power : 3000W,
    topology : Phase shifted full bridge with LC output filter
    Yes, it is a perfect fit. UCC21520 is a two channel universal gate driver and it can be used for high and low side, half-bridge, two low side and two channel in parallel applications.

    3,I am facing noise related problems with my present gate driver IC where the switching frequency noises are coupled back to
    controller PWM pulses.Will UCC21250 have similar issues?

    WIth proper PCB layout, there should be very little noise coupled to the primary side ground. The isolation capacitance is about 1.2pF, which is very small. A bench test of (common mode transient immunity) dv/dt for UCC21520 is over 100V/ns for all the corners, including Si process, VCCI, VDDA, VDDB range as well as temperature from -40C to 125C. the typical value of dv/dt is over 150V/ns.


    4, The datasheet mentioned in the website provides limited information.Is this product available in market?
    the product and full datasheet will be online by the end of this month.

    5, kindly share application notes,schematics if available,since i couldn't locate from TI site.
    Yes, application note, EVM and its userguide will be available also by then.

    Thanks again and regards,

    Wei
  • 0 in reply to Wei Zhang
    Intellectual 620 points

    Hello Wei/Ritesh,

    sorry for the delayed response.

    Thanks for your immediate replies.Kindly look into the following waveforms with my present gate driver ADuM4223.

    The switching frequency is 25 kHz.The noise frequency is 10 MHz.

    It seems that the ground noise gets coupled back to the DSP PWMs as shown below.

    Topology : Phase shifted full bridge

    Can you assure that the issues what i am facing with my present isolated driver will be completely rectified using UCC21520?

    When Vdcin : 31V





    When Vdcin :32V ,Vdcout : 310 V


    When DC input is Zero



    Kindly write your suggestions/comments to solve the above issues.

    regards,

    Ramesh.P

  • 0 in reply to Ramesh Palanisamy
    TI__Intellectual 2061 points

    Hello Ramesh,

    I saw the waveform, and Yes, it is quite noisy. Could you please help confirm the following points?

    1. The driver is an isolated driver, are you using differential probes to measure the primary and secondary signals? do you measure the signal with tiny pig-tail loops?

    2. We recommend the there should be no overlapping between the primary side and the secondary side for minimizing the noise coupling. could you please refere to the layout section of the UCC21520 datasheet for layout recommendations.

    Please let me know if you have further questions.

    Wei