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TPS61291 bypass mode efficiency ?

Other Parts Discussed in Thread: TIDA-00484, TPS61291, OPT3001, HDC1080, TPS62730, TPS610981

Hi Sir,

My customer currently design IOT sensor box, need long life battery application,

So I  suggest him TIDA-00484, but him question TPS61291 at Bypass mode efficiency, can provide bypass mode efficiency data for me?

And how explain to him TPS61291 bypass mode benefits?

battery use 1.5V cover 3V 1S or 2S ( enduser decide)
sensor use HDC1080, OPT3001
heavy load 100mA for wireless transmit
typical load 3.5mA~35mA
light load 2.2uA~3uA

 

 

  • At bypass mode, the VIN is connected to VOUT with a 1.2ohm Mosfet and consume only 15nA current. it is easy to calculate the efficiency by modeling the device to a 1.2ohm resistor in series with the battery.

    this mode is very useful if the battery voltage is within MCU operating voltage range at the light load condition.
    so the customer battery could be one cell alkaline or two cell alkaline battery? what is the sensor and MCU operating voltage range?
  • Hi Jasper,

    Thanks for your reply.

    if we need to design Vin 2.2V~4.3V, output 3.1V
    consider battery life, target select TPS62730 (have bypass mode), but TPS62730 fix output 2.2V is not meet MCU and other device spce.

    We thought select low Iq buck-boost converter in suitable this case, if you have recommend and best solution, please advise me, thank you.
  • the input voltage range is strange. which kind of battery customer is using?
    from the input voltage range, it seem you need a buck-boost converter.

    or you can use ultra low quiescent current device TPS610981 to keep the VOUT not lower than 3.3V, then a low quiescent current buck to get 3.1V