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LM5161-Q1: Ths supply current of LM5161-Q1

takahiko yokota
Mastermind 7135 points
Part Number: LM5161-Q1

Hi

I get the questions from my customer about LM5161-Q1.
My customer use LM5161-Q1 as Fly-Buck converter.
My customer try to calculate entire the supply currents of this device for calculating the Tj.
This device's datasheet is written the input operating current with non switching.
But the this device's datasheet are not written the values during switching.
So they demand the following specs.
Could you tell me these values or the calculating method of the total supply current?
・The minimum and maximum value of the internal FET's Qg, Tr and Tf 
・The input current during switching
Best regards,
Yokota

  • 0
    TI__Prodigy 580 points
    Hi, Yokota,

    The input current during operating would vary with load power (Po) and input voltage (Vin).

    With the efficiency data (eff), total output power (Po) and input voltage (Vin), the input current during operation can be calculated through Po/eff/Vin.

    For Tj calculation, total power dissipated on the device is needed instead of input current.

    Thanks.
    Best regards,
  • 0 in reply to Ray Chen
    TI__Guru**** 191445 points
    Let me add a couple comments as well. In every datasheet that I know of, the Iq is always measured non switching. The non-switching Iq is a direct characteristic of the IC and can be measured directly at the IC using the ATE equipment. Switching Iq is a function of the closed loop application and the inductor is a factor as well as input voltage, output voltage and switching frequency.