TAS5822M: Over current problem on both channels

Michele Iandoli

Prodigy 30 points

Part Number: TAS5822M

Tool/software:

Hello,

we are working on a prototype consisting of TAS5822M which is configured with a microchip microcontroller.

So far, we have configured correctly the Amplifier (as PBTL mono) and we are sending the I2S signal.

If we power up the amplifier at 8/9 Volt no error is shown, we can see the right signal in the output channel.

If we power up the amplifier at higher voltage, even 100/200 mV higher it doesn't work and it shows OC error for both channels in the register 0x70.

These are the registers that were read when the amplifier is powered by a voltage > 8V:

0x68 -> 0x01

0x70 -> 0x03

0x71 -> 0x00

0x72 -> 0x00

0x73 -> 0x00

We also tried to increase the voltage after the start up. Initially we powered up the amplifier with 8V and by increasing the PVDD it works untill 20 Volt then it shuts down (the audio signal in the output becomes nothing).

We also burnt one amplifier while trying to use a higher voltage to power it up.

this matter is in great urgency so I look forward to your response.

Kind regards.

2 months ago

0 Sydney Northcutt 2 months ago

TI__Mastermind 18380 points

Hello,

Thanks for reaching out. Please expect a response in 24 hours.

Regards,
Sydney Northcutt

0 Sydney Northcutt 2 months ago in reply to Sydney Northcutt

TI__Mastermind 18380 points

Hello,

Thank you for your patience.

Is the fault occurring at startup or after you start playing audio data?

Can you share schematic and layout?

Regards,
Sydney Northcutt

0 Michele Iandoli 1 month ago in reply to Sydney Northcutt

Prodigy 30 points

Hello,

at the start up we are measuring 10 mA, which, we assume, indicates the amplifier is in sleep mode. When the amplifier works fine, we are measuring 30mA. Immediately after the start up, the registers are read with the following errors:

0x68 -> 0x01

0x70 -> 0x02

0x71 -> 0x00

0x72 -> 0x00

0x73 -> 0x00

This is the oroginal schematic:

We made the following changes:

The transformer T1 is not mounted;

added a 0.68 uF capacitor after L2 and another after L7;

added 390 uF capacitor between Pvdd Pin and GND;

mounted a 10kOhm pull-up resistor for PDN pin.

soldered a copper sheet on the bottom pad of the amplifier and it is connected to ground.

These are the layouts top and bottom without the mentioned modifications above.

BOTTOM.pdf TOP.pdf

thanks for the reply and kind regards.

0 Sydney Northcutt 1 month ago in reply to Michele Iandoli

TI__Mastermind 18380 points

Hello,

I was able to review the schematic and all the changes I would recommend were included in your modifications. Did you notice any performance difference with the modified configuration?

I am reviewing the layout in parallel.

Regards,
Sydney Northcutt

0 Michele Iandoli 1 month ago in reply to Sydney Northcutt

Prodigy 30 points

Hello, yes we did see difference. Before the modification it didn't work at any voltage.

I would also llike to inform you, that our office we'll be closed untill 1st of September.

Kinds regards.

0 Sydney Northcutt 1 month ago in reply to Michele Iandoli

TI__Mastermind 18380 points

Hello,

Great. Is the output now what you expect? Feel free to update here when you return to office.

Regards,
Sydney Northcutt

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TAS5822M: Over current problem on both channels