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TPS40422: -

Pramath HS
Prodigy 10 points
Part Number: TPS40422

Hi,

I want to understand the current consumption of TPS40422 device.

Application details:

1. Driving external MOSFET

2. Vout1 & Vout2, different voltage rails.

3. Output current: ~20A each

5. BP3/BP6 regulators , no external loads.

TPS powered by 12V rail.

Datasheet: 

What is the current consumption of the device when switching ? and the power dissipation of the same.

As the max capacity of the LDO is mentioned as 120mA.

What should be considered for my application ?

As the Pd can be either 12V*25mA or worst case: 12V*120mA. Hence this information is essential

Thank you,

-Pramath

  • 0
    TI__Guru 63370 points

    Hi

    It is holiday and team will get back to you tomorrow 

    Regards

    yihe

  • 0
    TI__Mastermind 27500 points

    Hello,

    The device total current consumption has 2 components (assuming PB3 is not externally loaded):

    -  Input operating current with switching and no driver load Ivdd. The upper limit is 25mA specified in the datasheet

    - Drivers current is supplying the power FET gates. There are 4 drivers and the total current from VDD is 4*Qgc*Fsw (assuming the same FET for high sides and low sides). Where Qgc is the gate charge for each FET and Fsw is the device switching frequency.

    The total current consumption is Ivdd + 4*Qgc*Fsw. The total power dissipation is (Ivdd + 4*Qgc*Fsw)*Vdd.

    Example: Qgc = 10nC, Fsw = 0.5MHz, Vdd = 12V, Ivdd = 25mA

    Total current consumption = 25mA + 4*10nC*0.5MHz = 45mA

    Total power dissipation = 12V*45mA = 540mW.

    Regards