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TPS25910: Maximum Load Current at Startup

Wilfried Hermann
Prodigy 60 points
Part Number: TPS25910

Hi,

the Maximum Load at Startup is:

"Rmin=(Vin^2)/12.

Adding load capacitance may reduce the maximum load wich can be present at start up"


I would like to power up an electronic device with a power consumption of 1.5A@12V. The capacitive load is approx. 200µF.

With the formula above the TPAS25910 will never power up a device with power consumption of 1A@12V!?

Can you give me an explanation of this behavior?

  • 0
    TI__Guru** 102701 points
    Hi Wilfried Hermann,

    The limitation on max. startup load is due to constant power characteristics of TPS25910 device architecture.
    Please look at TPS259261/TPS259271 devices
    Can you help with more information..
    what is your application use case and end equipment?
    what is the max. input voltage?
    What is being switched/protected?

    Regards,
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 60 points

    Hi Rakesh

    I design a new product series. The power supply of this series is an external power supply. The power switch can only switch currents of max. 200mA; so I have to integrate an electronic switch or a relay :-(
    Also the customer can plug in the12V  power supply wich causes high inrush currents for a short time (150µF input capacitance).
    So I want to limit these currents.
    I had quick look to the TPS259261/TPS259271 and this looks fine.
    The most important information is the Thermal Shutdown Limit Plot.
    With this information I can dimension the circuit. :-)

    This important information is missing in the TPS25910 datasheet.

    Thanks a lot!

    Regards,
    Wilfried

  • 0 in reply to Wilfried Hermann
    TI__Guru** 102701 points
    Thanks Wilfried for the details.
    You can make use of design calculator to size your parameters www.ti.com/.../toolssoftware
    Let me know if you need any further help.

    Best Regards,
    Rakesh