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TPS61096A: What is typical quiescent current during OPERATION ?

JohnO47112
Prodigy 235 points
Part Number: TPS61096A
Other Parts Discussed in Thread: BQ25504

I have bq25504 evaluation board which energy harvests from indoor light using a small solar panel. I am going to feed the harvested energy to a smoke alarm at 10V to replace the usual 9V alkaline battery used in such smoke alarms. My bq25504 evaluation board outputs 3.2V nominal and I am looking at the TPS61096A device to step the voltage up to 10V. The device doing the step-up must be "as low energy consumption as possible". I do not plan to use the shutdown feature of the TPS61096A - the load should never be disconnected by definition for a smoke alarm. SO!, MY QUESTION: What is typical current consumption of TPS61096A during normal operation when it will be supplying a maximum of 10uA to the smoke alarm for all time  ?

Best Regards,  John O'Connor

  • 0
    TI__Mastermind 21565 points
    Hi John:
    There is a typical efficiency figure as Fig 1 in datasheet.
    Please note that the efficiency is different with the device and environment, even with the same condition.
  • 0 in reply to Minqiu Xie
    Prodigy 235 points

    Hello Minqiu,

    thank you for your reply. My question is not about efficiency, my question is about Quiescent current in operation. The TPS61096A will NEVER be in shutdown in my application, it will be operating normally all the time feeding a load of around 10 micro amps. What is typical Quiescent current in operation ? The 2 level shifters will NOT be used, are NOT needed.

    Best Regards, John O'Connor

  • 0 in reply to JohnO47112
    TI__Mastermind 21565 points
    Hi John:
    Quiescent current is tested with No load, No switch.
    Your circuit has 10uA load, so the Fig.1 is more suitable for you.
  • 0 in reply to Minqiu Xie
    Prodigy 235 points

    Hello Minqiu,

    Thank you for your reply. It is the TPS61096A device my question is about.  Figure 1 in the TPS61096A datasheet does apply to my application, but I am NOT interested in EFFICIENCY too much. I am interested in the total average current which will be drawn from Storage for all time in my application. This will comprise a 10uA to supply the external load, plus the QUIESCENT OPERATING CURRENT of the TPS61096A. So the device will be switching and will have load.

    From Section 6.4 Electrical Characteristics on page 5 of SLVSE09A –APRIL 2017–REVISED APRIL 2017 TPS61096A Datasheet  we have:-

    IQ_VIN  Quiescent current into VIN pin, Device enabled, no load, no switching   2.5 μA          So, nominally my full drain current from storage will be 10uA + 2.5uA =12.5uA.  BUT it will be higher than this due to the switching - what order of magnitude increase over 2.5uA can we expect when device is switching - doubled, ten times ?

    Also, any tips you have on completely NOT USING the 2 level shifters so as to minimise their contributions to this quiescent operating current, would be much appreciated.

    Best Regards, John O'Connor

  • 0 in reply to JohnO47112
    TI__Mastermind 21565 points

    HiJohn:

    I thought we saw the same version datasheet with "Figure 1. Load Efficiency with Different Inputs". You could calculate the " total average current" by Iin=Vou*Iout/(Vin*Eff). while Vout=10V, Vin=3.2V, Iout=10uA. And the efficiency is close to 60%-70% as typical reference.


    The Iq listed in section 6.4 is not suitable for loading. Here is an application note with clear description.www.ti.com/.../slyt412.pdf

    May you share your system block, so that I'll understand your need better.

  • 0 in reply to Minqiu Xie
    Prodigy 235 points
    Hello Minqiu,

    MANY THANKS - we have got there ! The Application Note you suggested is just brilliant and what I needed to help me calculate more accurately my full drain current on my Storage in my application.

    Thank you for your time - I will hit the green This resolved my issue button now !

    Best Regards, John O'Connor