TAS5132: TAS5132 amplifier output stage issue

Peter,

What output level are you using when you feel the inductors heat up? Is the heat causing an issue?

Which modulation scheme are you using? What is your output load?

Please let me know your LC output filter Inductor part number and manufacturer.

Regards,

-Adam

Hi Adam,

Below is the info for your reference.

1)What output level are you using when you feel the inductors heat up? Is the heat causing an issue?

- TAS5132 is powered by VDC18V. The heat doesn't casue issue. The device is working as expected. 

2) Which modulation scheme are you using? What is your output load?

- TAS5132 is configurated M3=0,M2=1,M1=0 (PWM INPUT= AD modulation, OUTPUT CONFIGURATION=2 channels BTL output, PROTECTION SCHEME=BTL Mode). We also tried M3=0,M2=0,M1=0 configuration, inductors heat up problem is still occurring. The output load is 6ohm. Besides, by removing the load, inductor heat up still happen.

3.Please let me know your LC output filter Inductor part number and manufacture

- The inductor part number is CS0605-100M. See attachement for inductor data sheet.

Peter

E20-00349-01 A1.pdf

Peter,

You mention in your original post that you consider the inductor heating to be an issue. Then in the above reply you mention that "heat doesn't cause issue" and that "The device is working as expected". I am confused.

What issue are you trying to resolve?

Regards,

-Adam

Hi Adam,
Sorry for not being able to clarify my issue, which confused you. Although my audio system based on TAS5132 is working, but the inductors are being seriously heated up even when no audio is sent to the amplifier, which I think is abnormal. I'm trying to resolve the heating problem, which I would like to get your help. Did you find any problem with our schematic? Did those inductors we used cause heating issue?

Best regards,
Peter

Peter,

Looking at your inductors and schematic, I don't see an issue. 

How hot are these inductors getting?

Can you send me a screenshot of the output PCB routing? I want to check that the output traces and Grounding is adequate. 

Have you tried using a different inductor such as those found on the EVM? We use http://psearch.en.murata.com/inductor/product/%23B966AS-100M%3DP3.pdf

Regards,

-Adam

Hi,

The output inductors do not only carry the load current, they are also subjected to the ac magnetic field that is imposed by the carrier.

According to faradays law the magnetic field in the inductor ferrite is proportional to the applied voltage and inverse porportional to the core area. This means that a small inductor

is subjected to high magnetisation, both under load and no-load conditions, which causes severe loss - and even saturation-  in the ferrite material,  which heats up obviously

That is why a good ferrite output inductor has a relative large winding area. When I look at the datasheet of your inductor, it is very small, undoubtly is is subjected to very high magnetisation.

In combination with TAS chips and a supply voltage of 15V, I use SMT inductors minimum 12.5 x 12.5mm. Much better performance can be achieved using

proper high performace leaded inductors from  wurth, sagami  or codaca website.

regards

Geert

Geert,

Thanks for your recommendations!

Regards,

-Adam