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UCC28951: UCC28951 for shoot-through protection

Rock Shao
Expert 2995 points
Part Number: UCC28951
Other Parts Discussed in Thread: UCC21540, UCC28950

Hi,

May I aks the UCC28951 has shoot-through protection, where the high low side MOSFET is turned at the same time?

For input 600~800Vdc, there has a high-low side gate driver to recommend. thanks.

Regards

Rock

  • 0
    TI__Genius 9790 points

    Hi, Rock

    UCC28951 don't let OUTA/B or OUTC/D turn on at same time by using delay time between OUTA falling edge and OUTB rising edge, and OUTB falling edge and OUTA rising edge.  Same scheme on OUTC/D.

    Regarding to driver for four MOSFETS of phase shift full bridge with UCC28951, because UCC28951 is normally located on secondary side, the isolate driver is better. UCC21540 is the recommendation.

    BR,

    Yunsheng 

  • 0 in reply to Yunsheng Qu
    Expert 2995 points

    Hi Yunsheng,

    Thanks.

    For UCC28950 I has the following question

    Currently, in the design of the UCC28950 protection circuit, there are two questions to ask:
    1. When IC PIN2 is ACTIVE LOW, whether OUA, OUB, OUTC, OUTD, OUTE, and OUTF are all turn-off. Or is it only OUTB&OUTD and SR's OUTE&OUTF closed?

    2. When IC PIN5 is ACTIVE LOW, whether OUA, OUB, OUTC, OUTD, OUTE, and OUTF are all turn-off. Or is it only OUTB&OUTD and SR's OUTE&OUTF closed?

    Because SPEC did not see this related information, does TI have an explanation of this related information?

  • 0 in reply to Rock Shao
    TI__Genius 9790 points

    Hi, Rock

    1. When IC PIN2 is ACTIVE LOW,  OUA, OUB, OUTC, OUTD, OUTE, and OUTF are not turned off, but the duty cycle of transformer is 0%, OUA, OUB, OUTC, OUTD, OUTE, and OUTF are all in burst off status.

    2. When IC PIN5 is ACTIVE LOW, OUA, OUB, OUTC, OUTD, OUTE, and OUTF are all turn-off since IC is disabled.

    BR,

    Yunsheng

  • 0 in reply to Yunsheng Qu
    Expert 2995 points

    Hi Yunsheng,

    Thanks, but there have other questions.

    UCC28950 IC PIN14 is a function that changes the Delay time as the CS voltage changes.


    The upper of ADEL is connected to a 200K resistor to +5V, and the lower is connected to a 15K resistor to GND, and the CS PIN is not connected, which means that the voltage of ADEL PIN is fixed at 5V x 15k /(200k+15k)=0.348V

    What is the OUTA & OUTB DELAY time when IC PIN6 DELAB is set to 15K?

    How to calculate the formula, TI’s DESIGN TOOL EXCEL file is completely different from the DATASHEET calculation formula
    Which one is correct?

    Regards

    Rock

  • 0 in reply to Rock Shao
    TI__Genius 9790 points

    Rock,

    can you send me eamil on yunsheng-qu@ti.com, I can share the calculation to you.

    Yunsheng

  • 0 in reply to Yunsheng Qu
    TI__Genius 9790 points

    Hi, Rock

    I've send the calculation to you, and I will close this post.

    Yunsheng