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TPS63001 Inrush Current

Terry16065
Expert 1185 points
Other Parts Discussed in Thread: TPS63001

I have a customer who is experiencing >1A inrush current on the TPS63001 when they enable the regulator.  The input voltage is 3.4V and stable for more than 10ms before the regulator is enabled, Vin is connected directly to Vina.  Load is 10mA.

I know that a typical boost can have an inrush current before the chip starts up, essentially charging the output cap via the inductor with no control.  The TPS63001 has a battery disconnect feature, will this suppress this type of surge?  If so, should the app note http://www.ti.com/lit/an/slva307/slva307.pdf help in this case?

  • 0
    TI__Intellectual 1300 points

    Terry,

    The load disconnect feature is used to facilitate the shutdown process and will not come into play in this scenario. When the device is enabled, the average current limit ramps up to drive the output voltage to regulation. The inrush current is a product of this process and is limited by the max current limit, which is 2-A for this part.

    The 'Softstart and Short Circuit Protection' section in the data sheet explains this behavior in greater detail. Figure 17 and 18 illustrate the current limit ramp on enable.

    The app note you provided will prolong the soft start, but I suggest clarifying the basis of your customers concern over 1-A inrush current before you apply any additional circuitry.

    Please let me know if you need any more information, or if you have any additional questions now or after you speak with the customer.

    Thanks,

    Nick

  • 0 in reply to Nick Tseng
    Prodigy 60 points

    Hi Nick,

    Thanks for your response.  I guess the max in-rush then for this device is 2A, I was not really sure what it should be.  I do see the max switch current spec of 2A.  

    I was able to reduce the in-rush by reducing the output capacitance I had on this voltage rail.  I went from 42uF to one 10uF cap on the output and the in-rush is down below 1A.  Much better now.

    Thanks,

    Don