TIDA-01509: TIDA-01509 for wire break detection

Hello Wissal,

According to your description, that you want to detect the load presence at the PA output, I don't think the ISO1211 would really fit. The operational principle depends on certain properties of the input line: they must be standard digital input of Type 1 or Type 3. those have certain I/V characteristics that are not possibly valid for the PA output.

instead I would suggest to have a look on the following application note:
Class-D Amplifier External Load Diagnostics

I believe you can modify it to work for your case if you are not using Class-D.

Cheers,

Ahmed

Hello Ahmed,

Thank you very much for your help. This application is for sure more appropriate to my need.

I am using a class H amplifier with high power. Since the current is high, I was think about using a voltage and a current sensor for the input of the external load diagnostic. Also, I need the diagnostic to be done while the load is in use. ( because we can't detect when the load is in use )

Do you have any recommendation for the use of this solution in my case ?

Wissal

Hi Wissal,

Yes, load diagnostic feature on automotive class D amp exactly matched your requirement. It could detect the load condition before power stage begins to work.

For real-time I/V sense, I guess you may need some instrumental amps and also ADC. 

So do you need any help on class D device selection?

Regards,

Hao

Hello Hao,

Thanks for your help.

I am already using an amplifier.

I have one more question, in the documentation it says that "we first have ti ensure that the amplifier outputs reach a high-Z state". In my application I need to be sure that the diagnostics is done even when the load is used. So in this case the output of the amplifier will be a signal from low frequencies to 1kHz.

I tried to simulate the systen with Kicad, but the Pspice models of the op amp , so I don't know how it's going to react. Do you have an idea ?

Wissal

Hi Wissal,

Load diagnostic procedure can only be implemented after output stage is made to Hi-Z status. For example, if you are having an output signal playing, a load diagnostic command will interrupt the playing, and then do the diagnostic. This is for protecting the class D power stage and loading before playing.

Looks like you need a real-time I/V sense on the output. Would you like to use Op-amp or some current sensing devices to do this job?

Regards,

Hao

Hi Hao,

You're right. At first I was thinks about using a voltage and current sensing, use afterward comparators and differentiator  for detecting  low current and comparator for detecting  high voltage. The schematic got really complicated because of the frequency change in the signal and i am not of its reliability. So I was searching for something simpler since I am not an expert in electronics.

Wissal

Hi Wissal,

You may take a look at TAS2770, it has integrated I/V sense feature. Thanks!

Regards,

Hao