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Boost for using with a battery Li-MnO2 (3V) and a NB-IoT module.

Oscar Gomez Fuente
Expert 2066 points
Other Parts Discussed in Thread: TPS61099, TPS61023

Hi everyone,

I am trying to find a boost for my application. I have a battery Li-MnO2 (3V@ Max continuous current of 500mA) connected directly to a NB-IoT module. The problem is the peak current with the NB-IoT module, it makes a drop off voltage below 2.1Volts and the devices switch off. The power supply of my NB-IoT module has to be > 2.1Volts.

So I need a Boost with  4.0 > Vinput > 1.5V. When the Vin < (2.7 - 2.5) Volts (i.e.) The Vout = (2.7-2.5) Volts and when Vin > (2.7-2.5) Volts, Vout = Vin.

The NB-IoT module has an energy consumption of 3.5uA in deep sleep mode, so the boost has to be prepared for ultra-low power energy.

I've found this part number TPS610995, but it seems to be there are some issues with it, so Does anyone any other suggestion?

Best regards.

  • 0
    TI__Mastermind 46905 points

    Hi Oscar,

    what is the output current requirement for the NB-IOT? 

  • 0 in reply to Jasper Li
    Expert 2066 points

    Hi Jasper,

    It is around 500 mA at the maximum but you have to add around extra 60 mA, so the requirement is at least 600mA.

    Best regards.

  • 0 in reply to Oscar Gomez Fuente
    TI__Mastermind 46905 points

    Hi Oscar,

    the TPS61099 is not suitable for this application. 

    I would suggest TPS61023 with EN signal synchronous with idle mode and a schottky diode between battery and loading. 

    when the NB-IOT is in idle mode, the device is disable. the output voltage is approxiamtely Vbat-0.2V. the Vbat is actual high during this period as small output current.

    when the NB-IOT is in active mode, the device is enable. the output voltage of boost can be set to 2.6V. the actual VOUT is not lower than 2.6V

  • 0 in reply to Jasper Li
    Expert 2066 points

    Hi Jasper,

    There is a problem, we don't have a uController for enabling the EN signal, that is to say, the NB-IoT has to be all the time on (deep sleep mode) because it has an internal ucontroller which is managing the application. So we need a boost with a very low quiescent current from VOUT in light load condition. 20 uA is too much.

    The NB-IoT in sleep mode has an energy consumption of 3.5 uA, so the whole system would have to be at most 6-8uA.

    Do you have another suggestion?

    Best regards.

  • 0 in reply to Oscar Gomez Fuente
    TI__Mastermind 46905 points

    Hi Oscar,

    there is no a logic signal out of internal ucontroller to indicate that if the NB-IOT is in deep sleep mode, correct? 

    if so, the TPS610994 is the closed solution if the WCSP package is acceptable. 

  • 0 in reply to Jasper Li
    Expert 2066 points

    Hi Jasper,

    1º. According to: "there is no a logic signal out of internal ucontroller to indicate that if the NB-IOT is in deep sleep mode, correct? "

    Yes.

    2º. According to this: "if so, the TPS610994 is the closed solution if the WCSP package is acceptable. "

    Yes, but I would rather use the TPS61099 vs TPS610994 that the output is adjustable and I can set the output for example to 2.5Volts . But I was reading in the forum that with this IC there are some issues.

    Best regards.

  • 0 in reply to Oscar Gomez Fuente
    Expert 2066 points

    Hi Jasper,

    1º. Would you mind answering my questions from the previous message?

    2º. Besides, I have another question related to TPS61099. According to the datasheet I can see there is WSON package for the TPS61099:

    But I can't find the part number for this IC. Would you mind helping me?

    Best regards.

  • 0 in reply to Oscar Gomez Fuente
    TI__Mastermind 46905 points

    Hi Oscar,

    sorry for the late.

    1. if the TPS61099 is set to 2.5V. the device would operates at down mode if input is typical 0.5V higher. the efficiency at down mode is not good. that is why I hesitate to suggest setting the output to 2.5V. 

    the issue relates to this device is that the power supply can't be oscillate at UVLO range, which is between 0.5V~0.7V.

    2. unfortunately, the adjustable SON TPS61099 is not available right now.

  • 0 in reply to Jasper Li
    TI__Mastermind 46905 points

    Hi Oscar,

    I closed the post assuming that the problem is sovled by you. if not, just reply below.

  • 0 in reply to Jasper Li
    Expert 2066 points

    Hi Jasper,

    I've just received my EVB TPS61099EVN-768. And I am testing it. Up to now, everything is working fine.

    Thank you very much for your help.