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TAS5421-Q1: Bit setting in Status & load diagnostic register during speaker open load

Chin Wee Keat
Prodigy 70 points
Part Number: TAS5421-Q1

Dear Sir,

Questions:

1) In Status and Load Diagnostic Register 0x02, when the D4 bit (in a fault condition) will be set 1?

    Does it relate to /FAULT pin? Means will be set 1 when /FAULT is active?

2) In Status and Load Diagnostic Register 0x02, will D4 bit set 1 when open speaker load happens? 

3) What is the proper way to detect if there is speaker open load?  Can only read bit D2 in load diagnostic register?

Thanks.

Best regards,

Chin

  • 0
    TI__Mastermind 45085 points

    Hi Chin,

    During load diagnostics, the fault pin will assert when there is a Short to Ground, Short to Power, or a Shorted Load.  On an Open load the register will indicate an open load the fault pin will not be asserted, and the output will start to switch.

    This device can only detect an open load during load diagnostics and reading the register after load diagnostics is run will provide the information.

  • 0 in reply to Gregg Scott
    Prodigy 70 points

    Hi Scott,

    To confirm, does the fault pin relate to the fault bit D4 bit in Status and Load Diagnostic Register 0x02?

    Means D4 will be set 1 when fault pin is asserted, right?

    Thanks.

    Best regards,

    Chin

  • 0 in reply to Chin Wee Keat
    TI__Mastermind 45085 points

    Chin,

    The fault pin and the register bit D4 are asserted for Short to Ground, Short to Power and Shorted Load.  With an Open load, bit D4 will be set but the fault pin is not asserted.

  • 0 in reply to Gregg Scott
    Prodigy 70 points

    Hi Scott,

    Besides the fault occurs at load, will bit D4 bit be asserted for other likes over voltage, under voltage and over temperature? 

    Best regards,

    Chin

  • 0 in reply to Chin Wee Keat
    TI__Mastermind 45085 points

    Chin,

    I will try to clear this up for  you. 

    Register 0x01 is the fault register.  This is a latched register that holds the fault value.  Is is cleared by cycling the /STANDBY pin. The following faults are indicated:  Overtemperature, DC offset, PVDD Over voltage, PVDD undervoltage, Over current, and load diagnostics.

    Register 0x02 is a status register and is cleared automatically when the condition is cleared.  Any load diagnostic fault condition will be reported here, when the load diagnostic fault is fixed, it will clear the bit.  When the fault is cleared it will clear D4, but the fault will be sticky in register 0x01. 

    The Fault pin will be asserted under all fault conditions and all load diagnostic fault conditions, except for open load.

  • 0 in reply to Gregg Scott
    Prodigy 70 points

    Hi Scott,

    Thanks for details explanation.

    1) When the fault is cleared it will clear D4, but the fault will be sticky in register 0x01.  => Does it mean any fault in register 0x01 will assert bit D4 (register 0x02) too?

    2) My understanding register 0x02 can only be refreshed by cycling /STANDBY pin, right?

    Sorry for many questions asked as there is problem happened where we detected  fault from the D-amp.

    Software implementation is reading all bits D0,D1,D2,D3,D4 (in OR coding) in register 0x02. 

    But we did not know which bit is actually asserted. 

    We needs to find out the possibility that caused the fault especially bit D4 when it is asserted.

    Thanks.

    Best regards,

    Chin 

  • 0 in reply to Chin Wee Keat
    TI__Mastermind 45085 points

    Chin,

    This has been taken offline with your local applications engineer.