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TAS5731: TAS5731

KYUNG SOO YANG
Prodigy 30 points
Part Number: TAS5731
Other Parts Discussed in Thread: LM3488

Hi!

I am Rishi

I got current consumption issue

Without any sounds, TAS5731 spends . 100mA/12V

From TI DATA SHEET 

What are the meaning of Normal mode & Reset and...do you have current consumption data more detail

  • 0
    TI__Mastermind 25815 points
    Hi Rishi,

    Normal mode has both the PDN and reset pins set high (so the device is not in reset and not in power down mode) with the test conditions noted above the table in the datasheet (TA = 25°, PVCC_x = 18 V, DVDD = AVDD = 3.3 V, RL= 8 Ω, BTL AD mode, fS = 48 kHz).

    What current consumption data are you measuring on your device and looking for? Is the 100mA @ 12V that you measured the PVCC supply current or the 3.3V supply current or the sum of the currents in both supplies?

    I am not sure how much decreasing the PVCC voltage from 18V to 12V changes the current draw, but I can check this on the EVM if you like.

    Regards,

    Alex
  • 0 in reply to Alex Bhandari-Young
    Prodigy 30 points
    Dear Alex

    Thank you for your reply

    100mA @12V only for Boost 18V IC to PVCC (100mA@12 ----> 67mA@18V)
    From above current data, PVDD spends 32mA to 50mA @18V normally

    I thought my device current spends too much compare to ref TI data
    Could you give me a guide for lose the current consumption at Normal mode?
  • 0 in reply to KYUNG SOO YANG
    TI__Mastermind 25815 points

    Hi Rishi,

    To clarify you are running the TAS5731 at 18V and using a boost converter to regulate a 12V supply to 18V?

    Do you know what the efficiency of your boost converter is? I believe boost convert efficiency can vary between 70-90%. Your calculation assumes 100% efficiency, but 70% efficiency puts you below 50mA of current at 18V so I think this may be something to rule out. Is it possible for you to measure the current directly into the TAS5731 at 18V?

    Also are you using the same conditions used by the datasheet? TA = 25°, DVDD = AVDD = 3.3 V, RL= 8 Ω, BTL AD mode, fS = 48 kHz. Is it possible that you are using the device with a smaller load? Clarifying these test conditions will help us rule out potential causes for the higher current you are observing before looking into the schematic you are using.

    Regards,

    Alex

  • 0 in reply to Alex Bhandari-Young
    Prodigy 30 points

    Dear Alex

    I checked several thing from your guideline

    Yes Right  TAS5731 is running at 18V and using a boost converter to regulate a 12V

    LM3488 (TI Product) efficiency is around 90%

    and 4ohm Woofer & 8ohm Tweeter each channel

    AVDD = 3.3V

    EVM Current is 35mA@18V 

  • 0 in reply to KYUNG SOO YANG
    TI__Mastermind 25815 points

    Hi Rishi,

    At 90% efficiency for the LM3488: 100mA*12V/18V*.9 = 60mA current draw by the TAS5731 so you are right that this is a bit higher than expected. You said that you are running with a  4ohm Woofer & 8ohm Tweeter on each channel. The datasheet current readings that you referenced state that they are for "no load". Having those loads connected could be causing the additional current draw that you are experiencing.

    Regards,

    Alex