TPA3113D2: FAULT mode after power-up

Mark Naiditch

Prodigy 150 points

Part Number: TPA3113D2

Hello,

I build the test board for the TPA3113D2 amplifier.

Unfortunately, power amp gong to the FAULT mode (when shorted to the SD pin no automatic recovery observed).

After power-up short PWM burst observed, after that no PWM, PINS 25 (18) VDC= 2V

Testing conditions:

VCC = 12V

Vin_disconnected.

Gain: 20db.

PLIMIT: 5V or shorted to GVDD.

GVDD=7V.

Thank you

Mark

over 7 years ago

0 Adam Sidelsky over 7 years ago

TI__Guru 65830 points

Mark,

Shawn will respond to you soon.

Regards,

-Adam

0 Shawn Zheng over 7 years ago

TI__Mastermind 24835 points

Hi Mark,
This FAULT is triggered without input signal, right? I saw that you are using 10uF capacitors for APA input, could you please try to use lower caps(e.g. 0.47uF)?

0 Mark Naiditch over 7 years ago in reply to Shawn Zheng

Prodigy 150 points

Hi Shawn,
I disconnected input capacitors and connected external power supply.
Still have FAULT mode.
Thanks,
Mark.

0 Shawn Zheng over 7 years ago in reply to Mark Naiditch

TI__Mastermind 24835 points

Hi Mark,
Could you please try to connect the input pins to GND through 1uF caps? Does the issue still occur?

0 Mark Naiditch over 7 years ago in reply to Shawn Zheng

Prodigy 150 points

Hi Shawn,
Done,
Same result.

0 Shawn Zheng over 7 years ago in reply to Mark Naiditch

TI__Mastermind 24835 points

Hi Mark,
This is strange, there is no obvious isse in the SCH. Is it possibly a soldering issue? Could you please check the bootstrap capacitors? is there any failed components on the board? how manny board did you try?

0 Mark Naiditch over 7 years ago in reply to Shawn Zheng

Prodigy 150 points

Hi Shawn,
I have 5 board and all acting in the same way.
I isolated power amp from the rest of the board (independent power supply and input source with and without connected load) - no difference.

0 Mark Naiditch over 7 years ago in reply to Shawn Zheng

Prodigy 150 points

Shawn,

Also, if it will give you any ideas, attached you'll find power amp PCB portion.

Thanks

Mark

0 Shawn Zheng over 7 years ago in reply to Mark Naiditch

TI__Mastermind 24835 points

Hi Mark,
Thanks for your update. Could you please help to do the following experiment:
1. Change C103, C105, C109, C114 to 0.47uF capacitors. Connect the left end of the cap C103, C114 to GND.
2. Remove the tansformer L101 and L104 on the output.
3. Disconnect SDZ and FAULT, and power up PVCC. measure the voltage on the FAULT pin.
4. Measure the waveform on the OUT pins.
See if the device can work normally.

0 Mark Naiditch over 7 years ago in reply to Shawn Zheng

Prodigy 150 points

Hi Shawn,

I believe the problem was in in C105 and C109 capacitors leakage.

After replacing them to ceramic 1uF capacitors I observed a stable startup.

I think it would be beneficial to add to datasheet specs maximum input leakage current instead of mentioning only DC detect fault differential voltage. It is hard to measure DC voltage during amp shutdown.

Thank you for giving me an idea how to troubleshoot this problem.

Mark.

0 kai klaas69 over 7 years ago in reply to Mark Naiditch

Guru 140200 points

Hi Mark,

this leakage current issue is mentioned in section 8.2.1.2.5 of datasheet. Low leakage tantal of ceramic shall be used for the input caps. And 1µ caps are recommended, not 10µ. :-)

Kai

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TPA3113D2: FAULT mode after power-up