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TAS5414B Cannot leave HiZ mode

Marc Szymanski
Prodigy 20 points

Hi,

we are currently trying hard to get the TAS5414B running.

We do not have any problems with I2C. We could run diagnostics and the speakers are detected when connecte and open load if not connected.

However, we cannot leave HiZ mode. Following commands

write 0x9F to 9x0c (-->reset)

read 0x00 - 0x01 (clear faults 0x03@0x00 and 0x00@0x01)

read 0x00 -0x0 (clear faults 0x00@0x00 and 0x00@0x01)

write 0x5f to 0x0b (run diagnostics keep the rest as default)

read 0x07 (--> 0x00 diagnostics finished)

read 0x02 (--> 0x88 no speakers connect OK!)

read 0x03 (--> 0x08 channel 4 is connected OK!)

read 0x0c (-> 0x1f HiZ all)

read 0x05 (-> 0x0f HiZ all)

write 0x17 to 0x0c (-> set channel 4 to mute/non-HiZ)

read 0x0c (-> 0x1f HiZ all (nothing changed))

read 0x05 (-> 0x0f HiZ all (nothing changed))

Before and after each read/write command are several seconds... We use i2cget/i2cset on an embedded Linux system.

What should we do next??? Any hints?

We connected 220nF to the mute pin. Before it was pulled up with 10K to 3,3V does this do any damage?

Cheers,

Marc

  • 0
    TI__Mastermind 45085 points

    Hello Marc,

    The I2C codes look ok for the TAS5414B.  Since you had the /MUTE pin connected incorrectly, there is a possibilty that it is not working correctly.   The Mute pin must be allowed to charge and discharge the 220nF capacitor.  At mute the voltage on the capacitor is pulled to 6.5Vdc and then pulled low again after the output pins start switching.  The TAS5414B will pull the pin high and then low.  If this transition is not allowed by external circuitry, the device will never leave Hi-Z.  Please check the /MUTE pin with an oscilloscope to see if this transistion occurs.  If not, then it is possible the /MUTE pin was damaged by the incorrect connection.

  • 0 in reply to Gregg Scott
    Prodigy 20 points

    Hi Gregg,

    thank you for your answer. The /MUTE pin is working properly. We finally found the problem. Instead of two single separated inductors we had common mode chokes in the output lines. This lead to an over current faillure, which prevented the amplifier from going into mute and play mode. Everything is working properly, now.

    Kind regards

    Marc

  • 0 in reply to Marc Szymanski
    TI__Mastermind 45085 points

    Hi Marc,

    This is good news.  The output inductor cannot be a common mode type.