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UCC27524: Power Dissipation & Output Capacitance

Hayden_Hast
Intellectual 1515 points
Part Number: UCC27524

Hello,

I'm currently using the UCC27524 in my system to drive an IRLR3110 and I'm working on calculating the power dissipation of the system. 

Would you suggest using equations 4 and 7 from the datasheet to determine this?

Originally I was using the "CMOS Power Consumption and Cpd Calculation' App Note to determine the power loss in the system, but was unable to find the output capacitance of the UCC27524 driver stages. 

Per this post, it sounds like we don't have this parameter - did you ever go characterize it for the UCC27524?

 

Regards,
Hayden

  • 0
    TI__Intellectual 2805 points
    Hi Hayden,

    Referring to the post that you linked, the design team used a simulation to determine if the UCC27524 could operate at the specific antenna frequency. I do not believe any characterization was done but I can check with our test team on that. Typically the switching frequency is selected in order to keep the junction temperature within rated limits.

    I suggest using equation (4) or equation (6) if gate resistors are being used to calculate the switching losses.
    Equation (7) will give you the quiescent power dissipation.

    regards,
    Mateo
  • 0 in reply to Mateo Begue
    TI__Intellectual 1515 points

    Mateo,

    Thanks for the response above. Would like to clarify one more thing...

    In the schematic attached, Would ROL = 0.5ohm (internal Rol)  // 20kohm (external Rpulldown).  Just making sure we have the correct Roff, Ron, Rgate values for equation 6.

    UCC27524_SCH.docx

    Thanks,

    Hayden

  • 0 in reply to Hayden_Hast
    TI__Intellectual 2805 points
    Hi Hayden,

    For R_OL, If you want to use the worst case for power dissipation I would use 1Ω, (max R_OL).

    R_GATE will be approximately 39Ω because the 20kΩ shunt resistor will be negligible during the switching period.

    regards,
    Mateo