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TPS65132: Low-current Applications (≤ 40 mA)

K.Yaita
Guru 29720 points
Part Number: TPS65132

Hi Team,

My customer designed his system with TPS65132B and adopted 40mA mode as Figure 19 in datasheet.
However the actual VNEG maximum load current showed more than 40mA in his system, it shows around 45mA average current and 50mA peak (~10us duration).
So, I would like to ask the followings.

1)
What is occured if VNEG load requires more than 40mA under 40mA mode?
I believe TPS65132B has current limit feature that limits VNEG output current up to 40mA(min) even though VNEG load requires more than 40mA.
Is my understanding correct?

2)
Should he change the schematic from 40mA mode to 80mA mode in this case?
He wants not to change his schematic when possible.
Should he try to add output capacitor for VNEG?

Best Regards,
Yaita / Japan disty

  • 0
    TI__Expert 8010 points
    Hello Yaita,

    The device can handle up to 45 mA in smartphone -mode however only at room temperature. If the system and as well the device heats up the output current capability will also decrease and there we have 40 mA - max.
    As this is quite marginal your customer can test his application in 80-mA mode under all operating conditions with the 40-mA schematic, if he sees no problems its ok.
    What are the output voltages?

    Best Regards.
    Ilona
  • 0 in reply to Ilona
    Guru 29720 points

    Hi Ilona-san,

    I appreciate for your kind support.
    He set VNEG=-5.4V and didn't confirm any problem under Ta=25deg so far.
    I will suggest 80mA mode with the 40-mA schematic and have my customer evaluate under all operating conditions includes ambient temperature.

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    Guru 29720 points

    Hi Ilona-san,

    May I ask the following two questions?

    1)
    ------------------------------------------------
    The device can handle up to 45 mA in smartphone -mode however only at room temperature. If the system and as well the device heats up the output current capability will also decrease and there we have 40 mA - max.
    ------------------------------------------------
    Which is stringent condition high temperature (Ta=85C) or low temperature (Ta=-40C) for Negative output current capability (INEG) in smartphone-mode?

    2)
    Figure 46 shows VNEG load regulation up to 40mA in smartphone-mode.
    Is there any data that shows more than 40mA (up to 45mA or 50mA.. etc)  in smartphone-mode?


    It is great if you also have the data under Ta=-40～85C. 
    My customer wants to see the data just for reference.

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Expert 8010 points
    Hello Yaita,

    Let me check this and then I will reply asap.

    Best Regards.
    Ilona