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  • TI Thinks Resolved

TPA6404-Q1: 0x09 bit [2] and mosfet questions

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Replies: 3

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Part Number: TPA6404-Q1

Hi Team,

Here are two questions may need your kindly help.

  • Bit[2]

Which DC diagnostic fault refers to in bit [2] in register 0x09, such as S2G, S2P, OL, SL?

Verification step

1: 4 CHs are connected to 4ohm load respectively
2. Initialization data: 0x09=0x00; 0x2b=0x03, 0x04=0x00
3. Pull down the S2G and fault pin of one of them.

Question:

bit [2] has been set to 0, why is it pulled down?
Could you please kindly indicate the meaning of bit [2]?

  • MOS

The internal PVDD and outp/n of the IC are output through push-pull, using MOS tube.

If this is the case, there is also a body diode inside the MOS tube, as shown in Figure D6 (marked in red),

It is equivalent to a body diode and an external diode in parallel. Could you please indicate the function of adding this external diode?

  • hello Amellie,

       you attached picture is for battery short to output reverse protection setup. for Bit[2] definition, I will let Dylan follow up with you.

    regards

    linda

  • Amelie,

    Questions about register 0x09 bit 2.

    This bit controls whether to report this fault(S2G/S2P/OL/SL) to fault pin. When set to 0, they should be not reported to fault pin.

    Can you confirm your test steps:

    1: 4 CHs are connected to 4ohm load respectively

    S2G fault event should be added between step 1 and 2.
    2. Initialization data: 0x09=0x00; 0x2b=0x03, 0x04=0x00
    3. Pull down the S2G and check fault pin

    DC diagnositc is a one time diagnositc at startup. If device is already in play mode, then short event can;t be detected by DC diag, it will trigger a OC event, then the fault pin report OC event.  You can read device fault register to find it.

    Question about diode.

    In normal condition, the internal diode can handle this current. while when the bulk capacitance is huge and DCR in this path is too low, then current level would be very large(some time could be >80A), which will damage device. at this situation, an external protection diode would be required.

    Dylan

  • In reply to Dylan Yao:

    No Response in over a week.  We will assume this is resolved and will be closed.

    Regards,
    Gregg Scott
    Senior Application Engineer
    Mid Power Audio Amplifiers

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