TAS6424E-Q1: While Performing AC Diagnostic to read tweeter impedance Getting wrong Impedance value

Puneet Sahu

Part Number: TAS6424E-Q1
Other Parts Discussed in Thread: TAS6424-Q1

Tool/software:

Hi There,

I have connected two tweeter(4 ohm, 4 ohm) parallels to two speaker(4 ohm, 4ohm) to channel1 and Channels2 of tas6424-q1. Reading the impedance values from the registers(0x17 - 0x1A) but not getting expected impedance value.

Scenario:

1)Connecting tweeter(4ohm impedance) with parallel to Speaker(4 ohm Impedance).

2)Playing sine tone with 19kHz.

3)Perform AC diag

4)Read the impedance values from the registers(0x17 - 0x1A).Getting Impedance value around 5.3 Ohm(21*0.2496 Ω).

5)Stop Ac Diga

6)Remove tweeter and speaker

7)perform step:2),3)

8)Read the impedance values from the registers(0x17 - 0x1A). Here Expected value around 0 Ohm But Getting value 5.3 Ohm(21*0.2496 Ω).Its taking previous

Please Can you provide support for this issue?

Regards,

Ishak

over 1 year ago

0 Wei Qiu over 1 year ago

TI__Expert 5690 points

Hi Ishak.

Did you fully follow the datasheet steps?

BR.

Wei Qiu.

0 Puneet Sahu over 1 year ago in reply to Wei Qiu

Prodigy 110 points

Hi Qui,

Yes I am following data sheet steps all.

Regards,

Ishak

0 Wei Qiu over 1 year ago in reply to Puneet Sahu

TI__Expert 5690 points

Hi Ishak.

Maybe you can use a standard resistor to do the test again, and try to find if there exist some wrong operations,

BR.

Wei Qiu.

0 Puneet Sahu over 1 year ago in reply to Wei Qiu

Prodigy 110 points

Hi Wei Qui,
I followed the datasheet steps for AC Diagnostic but when second time we are trigger the AC diag same value is taking while we are not connecting any load.

what the meaning of standard register ?Here we are using registers(0x17 - 0x1A) for load impendence value. Please can you mentioned in details for standard register use.

Regards,
Ishak

0 Wei Qiu over 1 year ago in reply to Puneet Sahu

TI__Expert 5690 points

The standard resister means the impedance we already know, like 4Ohm load etc.

I will do the bench test to see if I can reproduce your problems and also will log the steps.

BR.

Wei Qiu.

0 Puneet Sahu over 1 year ago in reply to Wei Qiu

Prodigy 110 points

Hi Wei Qui,

Thank you so much for support.
Ok I will wait for your update.

Regards,
Ishak

0 Wei Qiu over 1 year ago in reply to Puneet Sahu

TI__Expert 5690 points

I try to use the PPC3 to do the test and the test result satisfy the expected.

use 4Ohm resistor.

You can follow the PPC3 or use attached excel to try again.

BR.

Wei Qiu.TAS6424 AC diagnostic calculation.xlsx

0 Puneet Sahu over 1 year ago in reply to Wei Qiu

Prodigy 110 points

Hi Wei Qui,

Just one doubt in code how to calculate impedance of tweeter and will inform its tweeter connected or open load.
While Same impudence diff speaker has give diff impedance value why this behavior are getting?

Regards,
Ishak

0 Wei Qiu over 1 year ago in reply to Puneet Sahu

TI__Expert 5690 points

Hi Ishak.

The calculation formula as below:

Typically, you can judge if the tweeter is connected or not by load changes.

Puneet Sahu said:
While Same impudence diff speaker has give diff impedance value why this behavior are getting?

You mean the same speaker impedance but detect different impedance by TAS6424R? How much the impedance difference?

Errors may be introduced during the measurement process, but the error values should be small.

BR.

Wei Qiu.

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TAS6424E-Q1: While Performing AC Diagnostic to read tweeter impedance Getting wrong Impedance value