TPA3128D2: VCC < 4.5V: Unable to get the amplifier to get powered properly

Keshav Nelavai

Part Number: TPA3128D2

Hello,

I have built the circuit the same as specified by the schematic in the datasheet and also cross-referenced the design with the evaluation board. The current draw is being limited to 0.1A and my VCC is around 3.3V. I am trying to power to amp with 12V. What could potentially be causing this?

Thanks,

Keshav

over 5 years ago

0 Robert Clifton56 over 5 years ago

TI__Mastermind 23310 points

Hi Keshav,

My colleague Andy will get back to you on this.

Best Regards,
Robert Clifton

0 Andy Liu (BMS) over 5 years ago

TI__Guru 52115 points

Hi Keshav,

Could you show me your schematic?

Do you have a TPA3128D2EVM? If so, can you see the same problem if you use the same power supply (12V) to power the EVM?

Andy

0 Keshav Nelavai over 5 years ago in reply to Andy Liu (BMS)

Prodigy 70 points

Hello Andy,

Thank you for the response. I am using this schematic from the datasheet. I have tried testing this configuration as well as with the following changes referenced from the evaluation board's schematic

1. SDZ (Pin2) connected to GVDD

2. SDZ (Pin2) connected to PVCC

3. SDZ (Pin2) and FAULT (Pin3) connected to PVCC

These changes didnt work either. I tried using another TPA3128D2 amp but that had the same issue. I do not own the evaluation board though.

Thank you,

Keshav

0 Xiaolin Qin over 5 years ago in reply to Keshav Nelavai

TI__Expert 6295 points

hello Keshav,

what is 12V power result? can device power up successfully? by the way, can you check device Power in have 4.5V, there is not any voltage drop due to long trace.

regards
Linda

0 Keshav Nelavai over 5 years ago in reply to Xiaolin Qin

Prodigy 70 points

There is something limiting the voltage. I have the power supply set to 12V but its only outputting the 3.4V that I mentioned. Also forgot to mention that I'm testing the chip on a breadboard. I connected a sin wave to the input and I am getting a sin wave at the output, but the chip is still not powering correctly.

0 Keshav Nelavai over 5 years ago in reply to Keshav Nelavai

Prodigy 70 points

I just rebuilt the circuit connecting only the power related pins and was able to power the device. This is without the circuit to control gain and without the line input. I will see if connecting those causes the voltage to limit.

0 Andy Liu (BMS) over 5 years ago in reply to Keshav Nelavai

TI__Guru 52115 points

Let us know if your problem is gone.

0 Keshav Nelavai over 5 years ago in reply to Andy Liu (BMS)

Prodigy 70 points

I've connected the gain circuit as well as the line inputs and the amplifier is powering correctly. However, the current draw at the moment is only 6mA and I am trying to figure how to get the current draw I need. The signal is passing fine through the amplifier but it is not being amplified. I have not connected the output LC filter or the EMI snubber.

0 Keshav Nelavai over 5 years ago in reply to Keshav Nelavai

Prodigy 70 points

I also noticed that connecting pins 29 to 30 and 27 to 26 decreases the current draw from 6ma to 2ma.

0 Xiaolin Qin over 5 years ago in reply to Keshav Nelavai

TI__Expert 6295 points

you need to get BST with CAP to OUTPUT pin connected.

Regards
Linda

0 Keshav Nelavai over 5 years ago in reply to Xiaolin Qin

Prodigy 70 points

Hello,

Sorry for the late reply. I just got a hold of the boostrap capacitors and I'm still having issues. At 13V, the amplifier is drawing about 24mA I checked the voltages at PVCC and AVCC pins and theyre reading 13V. However, the voltage at GVDD is very low and the signal is not being amplified. When I input a 4Vpp 1Khz sin wave, the amp outputs the correct signal but at very low voltage. I have rebuilt the circuit and am still finding trouble. Any suggestions on potential issues?

Thank you,

Keshav Nelavai

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TPA3128D2: VCC < 4.5V: Unable to get the amplifier to get powered properly