TAS5558 DRV632 Active Subwoofer have patter noise

Hi Customer,

Can you show more details about the pattern noise? Further , after the initialization, can you hear the noise further after playing music?

If you can share the initialization code, it will be helpful for the further analysis.

In addition, would you please help to share your schematic for noise analysis?

BR.

ALix Wan

Hi,

The output of TAS5558 is PWM, while the DRV632 is an analog input device. I guess you have a passive filter to do the PWM to analog conversion, right? The mismatch of the passive components can leads to the pop during the common mode voltage ramping up.

Could you post the schematic?

Also, are you holding the MUTE on DRV632 during the initialization? It can help to eliminate the audible artifacts during initialization.

Thanks!

Regards,

Sam

TAS5432-GB-V041.pdf

Hi,

Are you using TAS5342 as power stage? TAS5558 output should go directly to TAS5342. Could you explain the purpose to insert a DRV632?

Regards,

Sam

Hi, Sam(MPAA) Zhang.

         Sorry,I forget to change the schematic name. we are using the DRV632 output  PMM8 signal to the active subwoofer. 

the PWM1 PWM2 PWM3 PWM4 PWM7  directly  correspond to TAS5342(FL,FR,  SL, SR and  CE).    Noise generation when the tas5558 chip is initialized .

 There is no noise after playing the song.   

Hi,

I see. Are you holding the /Mute pin of DRV632 at low level during the initialization?

Regards,

Sam

Hi,ALix Wan.

    after the initialization,  There is no noise after playing music.

Hi,Sam.

       i  try  to  hold the /Mute pin of  DRV632 at low level,   after  the TAS5558 initialization,

 Noise will be heard at the moment of raising /Mute  pin of  DRV632 the level

Hi,

So looks like the problem is not related to the TAS5558 configuration, the pop noise only happens at the moment when the mute pin of DRV632 is released, right?

Regards,

Sam

Hi Jenkey,

According to DRV632 datasheet, there is a dedicate circuit to suppress the pop-click noise. If the TAS5558 is set to mute status(50% duty cycle output), when releasing the MUTE pin on DRV632, is the pop noise still audible?

Regards,

Sam

Hi,Sam.

     this  is my  test code.   When I switch the flag state，the pop noise still remains.    

there  i  have  set the tas5558 to mute status, when releasing the MUTE pin on DRV632, is the pop noise still audible.

void TAS5558_Mute(u8 flag)
{
	if(flag==AP_MUTE)     
	{
	GPIO_ResetBits(TAS_MUTE_PORT, TAS_MUTE_PIN);	//TAS5558 mute
	delay_ms(1);
	GPIO_ResetBits(SUBOUT_EN_PORT, SUBOUT_EN_PIN);// DRV632 mute
	}
	else
	{
	GPIO_SetBits(SUBOUT_EN_PORT, SUBOUT_EN_PIN); // DRV632 no-mute
	delay_ms(1);
	GPIO_SetBits(TAS_MUTE_PORT, TAS_MUTE_PIN);	//TAS5558  no-mute
	}  
}

Regards,

Jenkey

Hi Jenkey,

I think the pop noise comes from the mismatch of the passive network to convert PWM signals to analog input. Using higher accuracy resistors/capacitors may help.

TAS5558 is actually designed to drive audio power stage like TAS5634, TAS5342... while DRV632 is recommended to take a analog audio input from DAC.

Regards,

Sam

Hi,Sam!

     Refer to demo circuit, we need lineout output circuit.  So  we choose  the DRV632.TAS5548-5558EVM.pdf

Regards,

Jenkey

Hi Jenkey,

If you look at the DRV632 datasheet, i.e., the simplified diagram on the first page, it shows DRV632 takes the input from a DAC. TAS5548 is not a DAC, but a PWM modulator. Of course you can use low pass filter to convert the PWM signals output by TAS5548 to analog signals. However, the passive components forming the low pass filter can have mismatch between P/N terminals, which could result in some pop noise and setting up the common mode voltage during common mode voltage setup on the speaker terminals.

Is it possible for you to use a DAC to replace the PWM modulator TAS5548?

Regards,

Sam

Hi,Sam.

    Thank you for your patience and continued support.You let us know where our problems lie.  

we  need the  PWM modulator  TAS5548, So ,May be  we can  choose the TPA6138A2.

Regards,

Jenkey.