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UCC27714D fries and smokes

Kamyar Keikhosravy
Prodigy 230 points

Hi, I am using UCC27714D a full bridge driver and even though it suppose to handle up to 600V on its high voltage pins (High side driver) it fries. it starts working for a while and after couple of seconds it glitches and send wrong outputs and then fries. it is crazy. the current is 0.5A and the voltage bias is 14V. attached is the screenshot of the circuit I am using this unit in.

It is worth noting that only one the half bridge drivers burns.

also it burns with out+ and out- floats.

please advise.

All the Best.

  • 0
    TI__Intellectual 2061 points
    Hello Kamyar,

    Thanks very much for your message. I am working on it and will respond asap.

    Wei
  • 0 in reply to Wei Zhang
    Prodigy 230 points
    thanks, eagerly waiting
  • 0 in reply to Kamyar Keikhosravy
    TI__Intellectual 2061 points

    Hello Kamyar,

    Thanks very much for your patience.

    Could you please advise your switching frequency? if the switching frequency is very low, it is recommended to increase the gate resistance for each FETs. The potential root cause and consideration is discussed below:

    I see you use very large current FETs. These large FETs have huge parasitic capacitance and very large reverse recovery on the intrinsic body diode. These parasitics will introduce significant ringing on the switch node (middle points of the half-bridge), which might cause significant high dv/dt, i.e. dv/dt>>50V/ns.

    Could you please help run a double pulse test for the high side switch in the half-bridge with a inductor parallel with the low side switch (gate is off)? and capture a few zoomed in waveforms for the switch node ringing (dV/dt). that will help us understand the root cause.

    Best regards,

    Wei

  • 0 in reply to Wei Zhang
    Prodigy 70 points
    Hello Wei,

    I am responding on behalf of Kamyar.

    Our switching frequency for testing is around 30kHz, but we sweep from 20kHz - 100kHz. From the time of the original post, we have added another bootstrap diode with a fast recovery time in parallel to D4 on the schematic. We have also reduced the bootstrap capacitor to 0.1uF. We are seeing improved results, but there does appear to be ringing at the gates. I will put an inductor parallel to the low side switch and share the results soon.

    Thank you,

    Phillip
  • 0 in reply to Phillip Angell
    TI__Intellectual 2061 points

    Philip, Thanks very much for your feedback. My Email is w-zhang@ti.com. Maybe we can discuss over phone for your updates.

    Best regards,

    Wei