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TPS61161: What is the nominal/typical feedback current into the TPS61161?

Mark Pearson
Genius 12705 points
Part Number: TPS61161

I have an application for the TPS61161 in a purely Boost DCDC mode (voltage output - not an LED string):

30V boost - want to minimize current in FB divider - currently set to about 35uA.

I have feedback in the system to adjust output (voltage) level using pwm. 

If I knew the FB bias is 1-2uA rather than 0-2uA, that would be helpful.

I would like to increase the FB resistors if possible, and knowing this information can help me with tolerances.

Thanks!

  • 0
    TI__Mastermind 22745 points
    Hi Mark
    The maximum current flow into FB is 2uA, this spec has been provided on datasheet. The FB resistor doesn't have much influence on the FB bias current.
    Regards
    Sean
  • 0 in reply to Sean Zhou
    TI__Genius 12705 points

    Hi Sean,

    Thanks for your response. Correct - the maximum leakage current into the Feedback pin is 2uA and, also yes, the FB resistors do not have influence on this variable.

    But what I I'm actually asking about is the typical value of the leakage current. The application is for a dynamic output voltage boost conversion, not an LED application - so I will have 2 feedback resistors (no LEDs). I want to maximize the feedback resistors (minimize the current burden of the design). But, the lower the feedback resistor string current, the more error the leakage current will have. This is why I want to know what the typical value of the leakage current is.

    I hope this helps in the understanding of what I'm after & why.

  • 0 in reply to Mark Pearson
    TI__Mastermind 22745 points
    Hi Mark,
    Understand it, but I'm sorry I don't have the typicl value for this spec, but for you application, you can just use 2uA as the typical leakage current to choose the resistor. In this way you can make sure every device can get similiar performance, right?
    Regards
    Sean