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LMG3522R030: paralleling LMG3522R030

Imre Kiss1
Intellectual 510 points
Part Number: LMG3522R030

Tool/software:

Hi,

We are considering paralleling up to 4 of the LMG3522R030 or similar GaN devices with integrated drivers.  Is this practicable and if so, are there any special considerations.

Thank you

  • 0
    TI__Intellectual 1220 points

    Hi Imre,

    A decoupling inductor is recommended to place at the SW node for hard switching based topology to improve the dynamic state performance. This is based on our lab test for paralleling 2 half-bridges. Decoupling inductors in the range of 1uH can accommodate delays & mismatch at transient condition and reduce switching loss/over-stress on fast turn-on switch. A similar approach can be adopted for paralleling 4 half bridge units.

    Thanks,

    Subhransu

  • 0 in reply to Subhransu Satpathy
    Intellectual 510 points

    Thank you for your response. I would like to clarify a few points regarding the recommended decoupling inductor:

     

    You mentioned placing the decoupling inductor at the SW node. Since the switch has both a source and drain, could you specify exactly where the SW node is in this context?

     

    Our application is a three-phase inverter, and the motor itself provides significant inductance. Given this, would a decoupling inductor still be necessary for our setup? If so, how would its role differ from that in your lab-tested configuration?

     

    I appreciate your insights and look forward to your recommendations.

  • 0 in reply to Imre Kiss1
    TI__Intellectual 1220 points

    SW node refers to the switching node, i.e. the point of contact between the source of TOP device and drain of BOTTOM device. 

    Please refer to the shown image:

    The motor inductance would add to the phase inductance. A decoupling inductor would still be needed for better current sharing and switching loss distribution between parallel half bridge units.

  • 0 in reply to Subhransu Satpathy
    Intellectual 510 points

    Again, thank you for your insight.  In addition, we were wondering if there are any useful application notes you can point us to.

    Thanks you,

     Imre Kiss

  • 0 in reply to Imre Kiss1
    TI__Intellectual 1220 points

    Hi Imre,

    Happy to support. We do not have any application note currently for this.

    Thanks,

    Subhransu