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UCC27524A: UCC27524A problem

xiao zhu25
Prodigy 170 points
Part Number: UCC27524A
Other Parts Discussed in Thread: UCC27524

Dear   All：

      I  use the UCC27524A to replace the IXDN604 that it    has  function  as same as  UCCA27524A， but when use the   switch frequency  100Khz   to test, the mos has  been  damaged , can you  help me  to  explain

what cause  the result,  By the way, the  damaged  mos  GS impedance is change low.  Thanks

  • 0
    TI__Genius 12990 points

    Hi Xiao,

    Thanks for your question, I am a High Power Driver apps engineer for TI and will help you out with this issue.

    For a pin to pin compatibility:

    UCC27524A is a 5A gate driver with an output resitance of 1.5R max. Able to achieve rise/fall times of 6ns. 

    IXDN604 is a 4A gate driver with an output resistance of 2.5R. Able to achieve rise/fall times of 10ns. 

    With more peak current of UCC27524A as well as less output impedance to limit the gate current its possible that when doing this pin to pin replacement with UCC27524A and IXDN604 the gate to source oxide of LS-FET becomes damaged either due to the excess ringing or higher gate current due to driving the gate harder with UCC27524A. This can be solved by adding more gate resistance to reduce the peak current and high dV/dt ringing.

    What FETs are you using? Can I see your schematic?

    Thanks,

  • 0 in reply to Jeffrey Mueller
    Prodigy 170 points

    Dear jeffrey:

        Thanks for you reply.

       As below is  the  schematic, pls it. 

       

  • 0 in reply to Jeffrey Mueller
    Prodigy 170 points
    Dear Jeff:

    thanks for your reply. and last Friday I reply the schematic , can you help give me more suggest to modify the gate resistance ？thanks.

    and I used the N-MOS Infineon IPW65R041CFD. Looking forward to your reply ,thanks！
  • 0 in reply to xiao zhu25
    TI__Genius 12990 points

    Hi Xiao,

    Thanks for your schematic, sorry for the late reply.

    I have a few questions to clarify:

    2) For HS fet ->

     - 12V_SA = Drain?

     - DRV_A1 = Gate?

     - DRV_GND1 = Source?

    3) For LS fet ->

     - 12V_SB = Drain?

     - DRV_A2 = Gate?

     - DRV_GND2 = Source?

    4) what is pin3 of D157/D160 connected to?

    5) what fet is damaged HS or LS? when is the fet being damaged turn off or turn on? 

    6) are you able to take scope shot of Vgs, IL and any other important waveform - for failing case fet?

    Thanks,

  • 0 in reply to Jeffrey Mueller
    Prodigy 170 points
    Dear Jeff:

    In the test condition，

    2) For HS fet ->

    - 12V_SA = Drain? ==== No , in the high drive voltage, the 12V_SA voltage is 12V ,
    in the low level voltage drive condition, the 12V_SA voltage is -2V

    - DRV_A1 = Gate? ===yes

    - DRV_GND1 = Source? ===yes

    3) For LS fet ->

    - 12V_SB = Drain? === No , in the high drive voltage, the 12V_SB voltage is 12V ,
    in the low level voltage drive condition, the 12V_SB voltage is -2V
    - DRV_A2 = Gate? ===yes

    - DRV_GND2 = Source? === yes

    4) what is pin3 of D157/D160 connected to? === floating

    5) what fet is damaged HS or LS? when is the fet being damaged turn off or turn on? === Both HS and LS are likely to be damaged. I

    6) are you able to take scope shot of Vgs, IL and any other important waveform - for failing case fet? === Sorry, My oscilloscope is broken., if you
    need waveform, i will take scope
    shot in two days later


    Thanks,
  • 0 in reply to xiao zhu25
    TI__Genius 12990 points

    Hi Xiao,

    Do the fets fail everytime you attempt to switch -> ie. you put 2 new fets on and they fail everytime? how many fails were achieved? how many attempts were made to make it fail?

    For the gate resistor value, try to compensate UCC27524 with the gate resistor difference of 1 or 2 Ohms - in order to match R_OH of IXD_604. This will allow the drivers to drive at a similar peak di/dt. Make sure you put at least an 0603 resistor so the pulsed gate current doesnt damage this resistor. The popuated 1206 sized gate resistor will be ok. Please update me if this solves your issue.

    Looking further into the DS differences I noticed that VCC recommended ratings for both parts widely differ. Since our part is of a lower voltage and If the noise is to high then this could be causing an issue with our part. This is probably not the cause, I thought I would just mention it.

     - UCC27524 VCC rating is 4.5 to 18V

     - IXD_604 VCC rating is 4.5 to 35V

    Thanks,