TPA2012D2: Short-Circuit Protection

Hi Sal,

There is no a similar device with Fault pin. But you could have a look at the following devices: TPA2016D2 and TPA2026D2. They have Short-Circuit protection and a Fault bit (Register1, bit3).

Best Regards
José Luis Figueroa
Audio Applications Engineer

Hi Jose,

it looks like during a short-circuit event, both outputs for the given channel go low.   For a over temp, it seems all four outputs would go low.   If we OR'd the left and right outputs each thru a 2 channel OR gate, would that effectively give us a FAULT signal?  Both channels indicating FAULT simultaneously would be indicative of a thermal shutdown.  Do you think that would work?

Best,

Sal

Sal,

The device outputs go to low duty cycle mode when a short-circuit event happens. I am not sure if the OR gate would work fine because the TPA2012D2's outputs are PWM and duty cycle will change according to the input signal. I think that the OR gate could experiment a weird behavior when the TPA2012D2 works normally.

Best Regards
José Luis Figueroa
Audio Applications Engineer

Hi Jose Luis,

can you describe operation of the short-circuit detect circuit in more detail?   Is it possible that a short between OUT+ of one channel and OUT - of the other channel could cause it to go into "low duty ratio" mode too?

Thanks,

Sal

Hi Again,
also, in addition to the above question, can you verify if a short-circuit occurred on one channel, would all outputs (even on the channel that didn't see a short- circuit event) go into the low duty cycle mode or should only the "shorted channel" pull its outputs low?

Thanks again,
Sal

Hi Sal,

I performed some tests with the TPA2012D2EVM.
For instance, the case where OUTL+ is shorted with OUTR- just one of the channels go to low duty cycle and another one continues working fine.
It seems that channels are independent of each other. If a short circuit is produced in one channel, so just this channel would go to low duty cycle another one continues working fine.
Please let me know your comments.

Best Regards
José Luis Figueroa
Audio Applications Engineer

Hi Jose Luis,
can you tell us more about your test set up?

We're not seeing the un-shorted channel continuing to operate.

. This is our procedure:-
• power the Audio Amp
• verify that both channels are switching.
• input audio identically into both channels

When we short either one of the channels, both channels go to “low duty ratio mode” . We're monitoring this on an oscilloscope - no switching and channels go low.

Are you doing something differently? Could it be that we're going into thermal shutdown instead?

Thanks,
Sal

Hi Sal,

I used the TPA2012D2EVM to perform the test. I configured the EVM based in the User's guide under the following conditions: Vdd=5V, Gain= 16V/V, differential inputs, RL=8Ω in each output and Vin=0.5Vrms. I mentioned to you the behavior previously.
Please let me know the results once you do the test.

Best Regards
José Luis Figueroa
Audio Applications Engineer