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TL5209 : What is the meaning of "minimum load current"?

Toshiya Hiramatsu
Intellectual 630 points
Other Parts Discussed in Thread: TL5209

Hi,

I have a question in the TL5209 datasheet.
What is the meaning of minimum load current?

I think that load current should be more than 1mA.
Is this correct?
Please correct me if I'm wrong.


Thanks & Regards,
Toshiya.

  • 0
    TI__Mastermind 36110 points

    The TL5209 must have a load current of 1mA or more to be stable.  If your actual load current is less than 1mA, you can size the feedback resistors to sink 1mA or more to ensure stability at all load conditions.  For example, if the output voltage is 2.5V and the load current can go to 0A, set the sum of R1+R2 (the feedback resistors ) to be less than (R1+R2) <= 2.5V/1mA = 2500ohms.

  • 0 in reply to Matthew Day
    Intellectual 630 points

    Michael-san,

    Thanks for the prompt reply.
    Your explanations became very significant for me.

    Thanks & Regards,
    Toshiya.

  • 0
    TI__Guru**** 165146 points

    Hello Toshiya-san.

    The main reason there is a minimum current specification is that even with the output transistor turned off there are other internal currents that flow to the output pin. If there was no load (<1mA) then the output voltage would exceed the programmed voltage. The TL5209 can only source current; it can’t sink current to maintain regulation.

    The data sheet says stability is the reason. Regardless of the actual cause there must be at least 1mA flowing either to the load or the feedback network.

    Regards,
    Ron M.

     

     

     

  • 0 in reply to Ron Michallick
    Intellectual 630 points

    Hello Ron-san,

    I was able to deepen understanding of TL5209 by your detail explanation.
    I express my gratitude to you.


    Thanks & Regards,
    Toshiya.