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BQ24090: BQ24090

Hugh Zhou
Prodigy 10 points
Part Number: BQ24090

I want to know the thermal protection logic of this chip; and after the thermal test, the result is different from the spec; I want to get the phone call with the FAE, thanks.

  • 0
    TI__Genius 12485 points

    Hello Hugh,

    Can you please specify how the thermal test differed from the specification? If possible, please include details relating to your test.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 10 points

    Under the 40 degree ambient temperature, the charging IC can't support  thermal protection; we tried two times, the result is same.

  • 0 in reply to Hugh Zhou
    TI__Genius 12485 points

    Hi Hugh,

    Just to understand, is this regarding the JEITA TS thermal protection or Junction Temperatur Thermal Protection?

    If this is regarding TS thermal proctection, please provide Thermistor values as well as Vts under the test conditions at test temperatures.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 10 points

    Could we set the teams call or phone call to clarify more clearly, thank you.

  • 0 in reply to Juan Ospina
    Prodigy 10 points

    For the BQ24090, there is no JEITA , right?

    It is regarding TS thermal, protection, could we set the meeting to further clarify, thanks.

  • 0 in reply to Hugh Zhou
    TI__Genius 12485 points

    Hi Hugh,

    That is right, my apologies. It is normal TS thermal protection that your are discussing. In this case, can you provide your thermistor value and beta. Can you share that portion of your schematic?

    Typically, it is best to go through your company's assigned FAE to set up this kind of meeting. If you do not have an FAE, we can continue this discussion via email.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 10 points

    Hello, I'm from Loreal, and currently there is no FAE supporting us. So if there is the FAE can help us, that will be helpful.

    For the BQ24090, the TS pin will detect the NTC voltage directly, and when this IC will trigger the OTP to stop charging?  and if the temperature is reduced, the OTP will be removed automatically, right? So when the charging will be recovery?

    what's the voltage to trigger OTP?

    what's the voltage to remove the OTP, automatically or not?

    which temperature to trigger OTP?

    which temperature remove OTP?

    what's the hysteresis characteristics?

    And if the ambient is lower than 0 degree, what will happen? and once higher than 0 degree, the charging will start, right? is there some hysteresis characteristics?

  • 0 in reply to Juan Ospina
    Prodigy 10 points

    What's the 45uA & 5uA mean?

  • 0 in reply to Hugh Zhou
    TI__Genius 12485 points

    Hello Hugh,

    Hugh Zhou said:
    For the BQ24090, the TS pin will detect the NTC voltage directly, and when this IC will trigger the OTP to stop charging?

    That is right. The TS pin outputs a 50uA current and detects the NTC voltage to determine temperature based on expected NTC resistance at different temperature. When the Vts < V(ts-45C) or Vts > V(ts-0C) then thermal protection will stop charging.

    Hugh Zhou said:
    and if the temperature is reduced, the OTP will be removed automatically, right?

    Right, if Vts drops below V(ts-45C) + V(hys-45C) then charging will resume.

    Hugh Zhou said:
    So when the charging will be recovery?

    If the temperature is above 45C, charging will recover when Vts > V(ts-45C) + V(hys-45C).

    Hugh Zhou said:
    what's the voltage to trigger OTP?

    To trigger thermal protection Vts must be < V(ts-45C)  (~278 mV) or > V(ts-0C) (~1230 mV).

    Hugh Zhou said:
    what's the voltage to remove the OTP, automatically or not?

    To remove thermal protection Vts must be > (V(ts-45C) + V(hys-45C))  (~288.7 mV) or > V(ts-0C) - V(hys-45C)  (~1144 mV). It will resume automatically.

    Hugh Zhou said:
    which temperature to trigger OTP?

    Below 0C or above 45C

    Hugh Zhou said:
    which temperature remove OTP?

    Very close to 0C or 45C, but because of hysteresis, it will be slightly higher than 0C or slightly lower than 45C. It will be dependent on your Thermistor beta characteristics.

    Hugh Zhou said:
    what's the hysteresis characteristics?

    Hysteresis is a margin given to the temperature threshold to prevent rapid switching on and off. So if Vts has some noise, the hysteresis prevents stop charging and resume charging multiple times.

    Hugh Zhou said:
    And if the ambient is lower than 0 degree, what will happen? and once higher than 0 degree, the charging will start, right? is there some hysteresis characteristics?

    Then charging will be disabled lower than 0C. It will resume once higher than 0 degree. There is hysteresis but it is not significant. This feature is designed for a thermistor that is placed next to the battery pack to monitor battery voltage, not ambient temperature.

    Hugh Zhou said:
    What's the 45uA & 5uA mean?

    These are the currents used to bias the TS pin. The current is constant so the resistance of the thermistor determines Vts.

    You can reference these images for voltage values. 

    Best Regards,

    Juan Ospina