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BQ25616: USB OTG Boost with low battery

Ue
Genius 17165 points
Part Number: BQ25616

Hi all

My customer is evaluating the BQ25616 using the  BQ25616EVM and they have this setup:

- No supply on VBUS

- Battery not charged

- Battery almost empty (< 3.0V, emulated with a power supply)

- USB OTC Boost function active

Question;With this setup the boost-converter seems not to work and the STAT-LED blinks with 1Hz, the reason is not clear. They suspect that the TS-Pin detects a "Hot Battery" and that therefore the boost-mode is turned off, REGN-supply is also not there.

Can one get the BQ25616 into boost-mode with low battery voltage ?

And 2nd question: On page 6 of the Datasheet TS_IGNORE is mentioned, although the IC doesnt have an I2C-interface to program any registers. How can one deactivate the TS-Pin ?

Best regards

Ueli

  • 0
    TI__Guru 57341 points

    Ueli,

    1.What's the VBAT pin voltage? The device will exit boost mode if VBAT<VBST_BAT.

    2. What's the TS pin voltage?

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Prodigy 130 points

    Hi Ning,

    The VBAT voltage is 3.0V and the TS pin is ~0V. I think the TS pin is 0V because the REGN-Voltage is also ~0V.  

    Best regards,

    Patrick (the customer)

  • 0 in reply to mopa
    TI__Guru 57341 points

    Patrick,

    1) It does not look like the device enters boost mode. REGN has output in boost mode. If you set VBAT=4.2V, will boost mode work? Please check 9.3.4 Boost Mode Operation From Battery on the d/s to see if all the boost mode conditions are met. Once the device enters boost mode, you may decrease VBAT to 3V and see if the boost mode still works.

    2) When TS pin is not used, connect a 10-kΩ resistor from REGN to TS and and a 10-kΩ resistor from TS to GND.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Prodigy 130 points

    Hi Ning,

    If the VBAT=4.2V then the device will enter boost mode and stays there even when the VBAT decreases below 3.0V.

    For my system design I have to make sure that the VBAT voltage is above 3.1V to enter the boost mode.

    Thanks,

    Patrick

  • 0 in reply to Ning T
    Prodigy 130 points

    Hi Ning,

    The V_REGN is 0.0V if the VBAT is below ~3.0V and regarding the datasheet the following conditions must be fulfilled to enable V_REGN:

    If my device is in boost mode without external power supply on the VBUS the first condition is not fulfilled, right? What is the minimal required voltage of the battery to enable the voltage V_REGN?

    Thanks and Regards,

    Patrick

  • 0 in reply to mopa
    TI__Guru 57341 points

    Ueli, Patrick,

    Since the inquiry is handled via separate channel, the thread is considered closed.

    Thanks,

    Ning.