• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 527 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS92511: Calculation for power dissipation

Satoshi
Guru 19655 points
Part Number: TPS92511
Other Parts Discussed in Thread: TPS92515

I think that calculation method for TPS92511 power dissipation is below, is it correct?

・Psw = 1/2 (Vin × Iout × fsw × (Trise + Tfall))

・Pcond = Iout^2 × RLX × Duty

・Pdrive = Qg × Vin × fsw

　⇒Pd_total = Psw + Pcond + Pdrive

　　※Without diode loss

And, Qg is gate capacitance for internal FET on TPS92511.

Is there spec data for Qg?

Best regards,

Satoshi

  • 0
    TI__Mastermind 28655 points
    Hello Staoshi,

    If it is not is the EC table it is not specified. An easier method to get this as well as the IC power consumption is to measure the input current to the TPS92515. That will give the gate loss as well as the IC bias loss. Pdrive will be much smaller than the other losses. what switching frequency is this running at?

    Calculations look reasonable, the freewheel diode can be a large part of the loss depending on duty cycle. Also there is loss related to the inductor as well as other losses, current sense resistor, etc.

    Regards,
  • 0 in reply to Irwin Nederbragt
    TI__Mastermind 28655 points
    I have not heard back from you so I believe you may have solved the issue.
    The thread will close now but will reopen if you reply.