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UCC27712: USING IN FULL BRIDGE WITH ONLY ONE CURRENT SENSE RESISTOR

Nicola Fiorucci
Intellectual 300 points
Part Number: UCC27712
Other Parts Discussed in Thread: TIDA-010023,

Based on TIDA-010023 EVM schematic i'm wondering if its possible to use only one resistor for sense the mosfet bridge current instead of three resistors (one for each leg).

Is this achivable?

How should i manage the COM pin for each UCC27712 using only one sense resistor?

My concern is that if i use only one resistor for sense the current i will increase the gate source loop for the low side mosfet.

Thanks

  • 0
    TI__Mastermind 20950 points

    Hello Nicola,

    Thank you for the interest in the UCC27712 driver and TIDA-010023. I am an AE with the High Power Driver group but not the expert on this board design. I will strive to answer your questions. You have a valid concern and question, and there will be a tradeoff in some respects regarding layout. We have seen designs sharing the resistor as you mention.

    For the layout I would strive to have the low side IGBT common emitter trace connection as short and low inductance as possible to the resistor shunt. A small plane would be a good idea to consider. For the driver COM connection,  strive to have a low inductance connection also to the input voltage filter capacitors with will reduce the layout inductance. The driver COM pin is referenced to the ground in the existing design, and also should be with changing to one share sense resistor. The driver COM pins ideally will be referenced to the kelvin ground from the sense resistor to the input capacitance negative terminal.

    Please confirm if this addresses your questions, or you can post additional questions on this thread.

    Regards,