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TLV320DAC3100: SPKVDD < AVDD ⟹ serious battery leakage?

Anonymous
Anonymous
Other Parts Discussed in Thread: TLV320DAC3100

Hi,

On page 44 of TLV320DAC3100 datasheet SLAS671,

If AVDD is powered through a regulator at 3.3V, and two SPKVDD pins are directly tied to 3.7V Li-ion battery output, then after some time the 3.7V battery voltage would fall to around its end-of-discharge voltage, say, 3.0V. Since AVDD is powered via regulator, it would still maintain 3.3V, but SPKVDD is just the battery voltage at 3.0V, then VSPKVDD < AVDD, how much battery leakage would it be in this situation?


Zheng

  • 0
    TI__Expert 4840 points

    Zheng,

    This typically does not happen. In a portable system the LDO's are normally powered by the battery.  So if battery supply drops the LDO output also drops. (unless you have two seperate batteries).

    The answer to your question is ~20uA.

  • Anonymous
    0 Anonymous in reply to Vins

    Vins,

    I searched through the datasheet, but it seems that there is no pin to put TLV320DAC3100 in sleep or standby mode?

    The description of [pin 31, RESET#] in §5.2.1 Device Initialization >> §5.2.1.1Reset seems only resets the registers, but does not control sleep/standby behavior.

    Is there a way to put the device into sleep/standby mode? In this mode (assume possible), if as described in the 1st post that


    If AVDD is powered through a regulator at 3.3V, and two SPKVDD pins are directly tied to 3.7V Li-ion battery output, then after some time the 3.7V battery voltage would fall to around its end-of-discharge voltage, say, 3.0V. Since AVDD is powered via regulator, it would still maintain 3.3V, but SPKVDD is just the battery voltage at 3.0V, then VSPKVDD < AVDD, how much battery leakage would it be in this situation?


    Would this assumedly existing sleep/standby mode further reduce the 20µA leakage current?



    Zheng

  • 0 in reply to Anonymous
    TI__Expert 4840 points

    Zheng,

     There will be leakage from AVDD to SVDD if SVDD < AVDD, even if the device blocks are powered down.

    There are different methods to put the device in low standby mode

    1) Power down each and every block

    2) Use the Software power down mode avalable in device

    3) SW Reset or HW reset the device (resets the registers)

     

  • Anonymous
    0 Anonymous in reply to Vins

    Vins,

    I think (1) is possible; however, I didn't find any possible implementation of (2) or (3) in TLV320DAC3100 datasheet. Were you giving generic suggestions or directly pertain to TLV320DAC3100?


    Zheng

  • 0 in reply to Anonymous
    TI__Expert 4840 points

    Zheng, option 2 and 3 are pertaining to DAC3100. The information is avialble in the D/S.

    Page 0/Register 1

    and Page 1/ Register 46

  • Anonymous
    0 Anonymous in reply to Vins

    Vins,

    I got it, thanks very much.

    Zheng