TAS5538/TAS5624A Output Phase Adjustment in Power-off Sequence

Sadanori Kato

Other Parts Discussed in Thread: TAS5538

Hi,

Our customer seemed the phenomenon that the output phase is adjusted by TAS5538 based on the power-off sequence.
The power-off sequence is shown as below.
Could you please give me your advice whether it is correct as that sequence?
In addition, does the phenomenon occur such as the output phase is adjusted in that sequence?
Please let me know as I send the customer's capture of the oscilloscope to your private e-mail if you need that.

Best Regards,
Kato

over 9 years ago

0 Tuan over 9 years ago

TI__Mastermind 33420 points

Hello Kato-san,

Is this for the headphone outputs and not the speaker outputs? What is the setting for 0x24? Please ignore the "Special Low Z" and "Mid Z", since they were not implemented. In this case the period is for volume ramp up and ramp down. If it is in default (124mS), then 200mS is enough.

Best regards,

Tuan

0 Sadanori Kato over 9 years ago in reply to Tuan

Guru 36490 points

Hi Tuan-san,

Thank you for your quick response.
Our customer would like to use the HP_SEL pin to improve the pop noise for the speaker outputs in the power-off sequence.
Do you have a experience such as the use case?
Is the volume gain update rate(0xd0 register) applied as the PWM ramp-down if using the soft mute(0x0f)?

Best Regards,
Kato

0 Tuan over 9 years ago in reply to Sadanori Kato

TI__Mastermind 33420 points

Hi Kato-san,

Sorry, we have not tested the use case you described above.

The volume gain update register timing is for changing from current volume setting to the next volume setting, e.g. from -9dB to -12 dB. Not for mute and unmute.

Best regards,

Tuan

0 Sadanori Kato over 9 years ago in reply to Tuan

Guru 36490 points

Hi Tuan-san,

Thank you for your support.
I understood.
In addition, could you please give me your advice about the following post?

http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/t/398173

Best Regards,
Kato

Audio

Audio forum

TAS5538/TAS5624A Output Phase Adjustment in Power-off Sequence