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TPS55289: Powering form a 26650 LFP battery

Johan Rosman
Prodigy 20 points
Part Number: TPS55289
Other Parts Discussed in Thread: TPS55288

Hello,

At the moment I am evaluating the TPS55289. I bought the EVM and am using the GUI to try it out.

As a power source I would like to use a 3.2V (nom) LFP battery.

The Vin_min of the device is 3.0Volts, which is very close to the nominal battery voltage.

In practice I can lower the Vin to approx 2.6Volts when it starts to fail.

Now, I was wondering, the TPS55288 has an even lower Vin min, of 2.7Volts is a better chocice.

But then I need to use external MOSFETs.

I succesfully tested the EVM to run on an almost empty battery ( 3% charge) and it workedOK ( +12 V / 200 mA from the almost empty battery)

Now, I was also wondering what exactly is the difference between the TPS55288 and TPS55289, because the Vin UVLO of both devices are exacly the same:

VVIN_UVLO Under voltage lockout threshold VIN rising 2.8 2.9 3.0 V VIN falling 2.6 2.65 2.7

So, if they both have the same limits , regarding Vin undervolts, The chocie for the tps55288 will not help in my case?

  • 0
    TI__Mastermind 28700 points

    Hi Johan,

    Thanks for reaching out. May I know what is the application and the product type here?

    As you mentioned, the VIN_UVLO rising and falling voltage of TPS55288 and TPS55289 are the same. And for the power level 12V/200mA, it is recommended to choose TPS55289 which is a full-integrated device and doesn't need external MOSFETs.

    TPS55288 is more suitable for higher power level with external MOSFETs and better thermal performance.

    BRs,

    Bryce

  • 0
    Prodigy 20 points

    Hi   Bryce, 

    The product type is a datalogger and the TPS55289 Will be used for powering sensors. Our current model datalogger has a fixed output of 12V/200 mA. But I thougt I would be nice to let the user select the (sensor power) voltage of his preference.  The current model uses the tps81061. Which appears to  be obsolete. Now the only thing I worry about is The operation on A low battery. 

  • 0 in reply to Johan Rosman
    TI__Mastermind 28700 points

    Hi Johan,

    I don't find TPS81061 on TI.com, is it a Boost converter? 

    As we talked before, the Vin falling voltage is 2.7V, what is the minimum voltage of the battery? I think it is above the 26650 LFP battery minimum voltage, pls correct me if I am wrong. So I think TPS55289 is suitable here.

    BRs,

    Bryce

  • 0 in reply to Johan Rosman
    TI__Mastermind 28700 points

    Hi Johan,

    We have not seen an update from you for three weeks, so I assume the questions are answered and the issue is solved.

    I close this thread now. If there is still something open, please reply and the thread will get opened again.

    If you have any other question or of the thread has been locked, please open a new one.

    Clicking the Resolved Button also helps us to maintain this forum.

    Best regards,

    Bryce