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current limit of the current-limited load switch

Markus Tamas
Intellectual 620 points
Other Parts Discussed in Thread: TPS22944, TPS22943, TPS22946, TPS2553, TPS2552

Hi,

I would like to create a 5V output with 100mA current limit. First, I thought that TPS22944 would be an ideal choice, but as I see on its  datasheet it will not really limit the current at 100mA. Therefore, I have to size the power supply to be able to supply 200mA and thus this load switch will lose its original purpose. Did I understand correctly the datasheet?

Could you please suggest me a suitable load switch for this purpose?

Thanks in advance!

Tamas 

  • 0
    TI__Expert 5275 points

    Hi Tamas,

     

    You are correct that the output current limit of the TPS22944 could be as high as 200mA.  100mA is the lowest the current limit will be; guaranteeing at least 100mA downstream.  From the typical graph in Figure 11, the expected current limit would be around 140mA. 

    There is also the TPS22943 which has a current limit between 40mA and 80mA.  Typical graph in Figure 13 shows around 65mA. 

     The TPS22946 might also be an option.  With CL= GND, the current limit will be between 70mA and 120mA (depending on input voltage).

    What are the minimum and maximum acceptable values for the current limit?

     

    Kind Regards,

    Adam Hoover

    Load Switch Applications Engineer

  • 0 in reply to Adam Hoover
    Intellectual 620 points

    Hi Adam,

     

    Could you please explain to me how can I read Figure 13? It plots Ilim vs Output Voltage, but on the horizontal axis Vin-Vout(V) is written. For me it is a bit confusing.

    Perhaps TPS22946 will be suitable. 70mA-120mA are acceptable limits.

     

    Thank you in advance!

    Kind Regards,

    Tamas

  • 0 in reply to Markus Tamas
    TI__Expert 5275 points

    Tamas,

     

    It would be more accurate to describe the graph as ILIM vs. Input Voltage.  The Vin-Vout label is correct since Vout was shorted to ground to measure the current limit as Vin was increased.

    Is the BGA packing for the TPS22946 acceptable?

    Let me know if you have any other questions.

     

    Regards,

    Adam

  • 0 in reply to Adam Hoover
    Intellectual 620 points

    Adam,

    Now the Figure is clear. Thank you for the explanation! The BGA packing is not the best, but perhaps we can accept it. However, I would be glad if you would have any other suggestion, a similar load switch in SC70 or in similar packing.

    Best Regards,

    Tamas

  • 0 in reply to Markus Tamas
    TI__Expert 5275 points

    Tamas,

     

    I think the TPS2552 or TPS2553 with max RILIM resistor would also work.  Available in SOT and SON package options.  Although it will likely be a more expensive solution since it was built to support up to 1.5A. 

     

    Regards,

    Adam