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LM5116: Shoot-through issue of LM5116

Harry Ma
Intellectual 2730 points
Part Number: LM5116


Tool/software:

Hi Team

The following LM5116 circuit，Vin=50V，Vo=3.3V，L=4.7uH，Cout=150uH，VCCX=12V，Enable the device after Vin is ready，but customer found LM5116 will output high side and low side driver signal simultaneously to cause shoot-through，and LM5116 will be damaged as well.

CH2 low side driver signal，CH4 high side driver signal，CH1 EN pin，CH3 COMP pin

Can you help to confirm if you see the same behavior for our device? why does it happen and how to address this?

  • 0
    TI__Guru 61621 points

    Hello Harry 

    Would you please capture higher resolution waveforms for my investigation ? 

    Please capture V(HO-SW) at the IC pin, V(Gate-Source) at the high-side MOSFET, V(LO-GND) at the IC pin, V(Gate-Source) at the low-side MOSFET. 

    I think the external gate driver circuitry is causing the problem. 

    -EL  

  • 0 in reply to EricLee
    TI__Intellectual 2730 points

    Hi Eric

    Thanks for your support, Pls refer to the following picture. 

    • V(HO-SW) at the IC pin, CH3
    • V(Gate-Source) at the high-side MOSFET,CH4
    • V(LO-GND) at the IC pin, CH1
    • V(Gate-Source) at the low-side MOSFET. CH2

    Another key message is: the device can work normally if EN device firstly, adding Vin then, adding VREF_1 lastly. 

  • 0 in reply to Harry Ma
    TI__Guru 61621 points

    Hello Harry 

    In order to check if any shoot-through or not, I need zoom-in waveforms....with about 50ns/div scale. 

    If the behavior changes by changing the start-up sequence, maybe it is not a shoot-through issue..  

    if EN device firstly, adding Vin then, adding VREF_1 lastly ==> This doesn't make it sense. the device cannot be enabled without applying VIN. 

    Please clearly describe the issue in detail for more investigation, and please share zoom-in waveforms. 

    -EL 

  • 0 in reply to EricLee
    TI__Guru 61621 points

    I will close this thread. and take this offline. Hello Harry Please use the email 
    -EL