TDF8546A

[sreekanthkaranam]

Hello,

In our project we are using TDF8546A power amplifier and we are facing an issue in the vehicle. 

When under voltage, over voltage or output stage high impedance is detected, we are doing a complete reinitialization of the power amp.
Which includes Restart the power amp, mute, run start up diagnostics , unmute -> This whole process is taking around 2 seconds. During this time, the user experiences an audio duck.

Is it a right action to restart power amp, run start up diagnostics in case of UV/OV ?

Is there any other correction action that can be taken in this case?

Best regards,

Sreekanth

[sreekanthkaranam]

Hi Jozef,

thanks for your response. Let me put my question in this way.

What is the corrective action I can take without impacting the audio,  if,

1. D6 or D7 bits of DB5 register are set to 1. 

2. D0 bit of DB5 register becomes 0. 

which basically indicate failure conditions on power amplifier.

Best regards,

Sreekanth

[JozefKozon]

Hello Sreekanth,

1. D6 or D7 bits of DB5 register are set to 1. 

[A] This is correct. The D6 is set to 1 if the supply overvoltage appears, and the D7 is set to 1 if the supply undervoltage appears.

2. D0 bit of DB5 register becomes 0. 

[A] The D0 indicates, that the amplifier is switched off. The amplifier behaves correctly. You need to restart the amplifier. 

Please refer to a paragraph in the section 7. in the TDF8546A datasheet. "If the input
capacitors are allowed to discharge quickly, a small input signal is caused by a different
input time-constant due to a different AC ground and input capacitor. This small input
signal would be amplified to the output resulting in an audible plop noise."

Larger capacitor on the SVR pin prevents this, but causes longer start up time.

With Best Regards,

Jozef

[JozefKozon]

Hello Sreekanth,

please refer to the section 7.1 in the TDF8546 datasheet. A capacitor on the SVR pin is used to smooth start up and shut down sequence, preventing the amplifier producing the plop noise. Please refer to Figure 38. for recommended SVR capacitor.

With Best Regards,

Jozef