TPA3220: design help

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Depeng Man said:

Question 1: according to the official data, when tpa3220ddwr is powered by 30V, when thd is 1%, 8 ohm power is 2 * 50W, and when thd is 10%, 8 ohm power is 2 * 60W. It is actually made according to demo parameters, which can not meet the official data. For the actual parameters, see my AP test diagram, attached figure 1. Schematic diagram, attached Fig. 2

Before go to the measured data, we need to look into test bench to confirm correct setup, to make sure voltage drop happens on DCR of components are low enough.

1. please check PVCC voltage, make sure pvcc ripple is not a factor which limit the peak output power

2. please check the DCR of 10uH inductor

3. please check the DCR of PCB layout is not limiting the measurement data. 

4. please check if speaker cable DCR is excluded.

Depeng Man said:

Question 2: according to the official data, the tpa3220ddwr provides 8 ohm thd = 10%, 2 * 60W continuous power, but in practice, it can only be 2 * 40W continuous power. When the sine wave is aged up to 1kHz, the protection time will become shorter and shorter with the increase of power. I consider that it may be related to the heat dissipation of my PCB,

This device is pad down, so thermal would be definitely an important factor, as Rds_on of FET will increase with higher temperature.

Please note: in audio application scenario, peak power is played with several cycles, not continuously play. That could be the difference of 40W@1%THD vs 50W datasheet specified. 

Also this point has been proofed by your test data by:

• continous run is 40W@1% THD
• at sweep THD vs PO plot, 1% THD is around 45W output.

Depeng Man said:

Question 3;   Tpa3220ddwr, under the condition of 26V power supply, the output power is 41w, which can produce continuous power. See Annex 3 / 4 for specific power and distortion. Similarly, under the condition of 30V power supply, the output power is 43W, which can only last about 30s. See firmware 5 / 6 for specific power and distortion,

i can not find the firmware 5/6. Audio device is not designed to continuous run at peak power. If need that, please use higher output power device with pad up thermal pad.

Depeng Man said:

Question 4;   Tpa3220ddwr, after protection, the fault pin outputs low level. After fault contact, it cannot be recovered automatically. It can be recovered only after the reset pin is reset, right? In the schematic diagram of Annex 1, check whether the circuit of R19 / R20 / R21 / R26 / Q1 / Q5 is feasible. After the fault protection action, Q5 turns on to make Q1 turn on, reset when reset is pulled low, and the fault turns to high level after reset. The actual test shows that the circuit cannot work normally, and the separate test is feasible. As long as it is closed-loop, it is not normal;

Excuse me, can automatic reset be realized after protection with tps3802k according to official data?

Yes, after OT shutdown, RESET toggle should be used to restart playing.

As to TPA3802K, please go to another forum for help.

By the way, just a tip here: use attachment document with good writing/graph style would be better experience for reading. Otherwise, it is quite difficult for me to follow all questions of you.

Hello!

After seeing the reply to the question, there are still some questions below. Please continue to help feedback. Thank you!

Question 1:TPA3220 the official continuous power is shown below. According to the reply from question 2, I understand that the continuous power on the technical data is not the continuous output under 1Khz, but the continuous power of the audio is this understanding?

Question 2: according to the reply to question 4, after over temperature protection, it can not automatically recover, and it needs artificial RESET switches to recover. Is that right?

The J13 on the DEMO principle diagram is the automatic recovery of the design? See the figure below:

Depeng, i will feedback after several mintus.

Depeng Man said:

from

Again, To answer the question1, we need to know below answers. otherwise a simple comparison with datasheet specified makes no sense.

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Before go to the measured data, we need to look into test bench to confirm correct setup, to make sure voltage drop happens on DCR of components are low enough.

1. please check PVCC voltage, make sure pvcc ripple is not a factor which limit the peak output power

2. please check the DCR of 10uH inductor

3. please check the DCR of PCB layout is not limiting the measurement data. 

4. please check if speaker cable DCR is excluded.

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5. additionally, need to check how good the thermal dissipation path from layout. 

Depeng Man said:

The J13 on the DEMO principle diagram is the automatic recovery of the design? See the figure below:

There is delay controlled by POR device.  Please check from customer circuit.

Dylan

Hi Dylan ,

Thank you so much！

I've conveyed it to my customer.

Have a good day .

James

TI technology team;

Hello! Reply has been received! I already know about the power problem. There is another problem encountered in the actual test that needs support. Thank you!

Problem 1:30V power supply, output power 2*42W, 8OHM, 1KHZ, continuous power output, THD+N<1% at this time, 3 minutes later, thermal protection.

26V power supply, output power 2*42W, 8OHM, 1KHZ, continuous power output, THD+N=6.5% at this time, very good, no thermal protection;

Under the same output power, why does high supply voltage have thermal protection? Is there a certain correlation between heating and supply voltage?

The problem 2:J13 is AUTO RETRY. Can the automatic reset be achieved after the circuit is short circuited? This question is not very clear?

Thank you.

Hi wang ,

Thank you so much！

I've conveyed it to my customer.

Have a good day .

James