TAS6424-Q1: Operating without load

Josef Warta

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

Hello Team, question from customer:

Are there any concerns if the TAS6424 is operating without load and filter for only a few seconds (<5s)? No signal but DC diagnostic and PWM on.

Background of this question. There are options on the PCB which have channels assembled without filter (channel not used) but SW doesn't know it during start-up.
After reading the configuration settings SW switch off these channels but this could take up to 5 seconds.

Many Thanks and BR

Josef

over 2 years ago

0 Gregg Scott over 2 years ago

TI__Mastermind 45035 points

Hi Josef,

If you try to turn on the device with DC diagnostics enabled and no load, the channel will not be allowed to go to Play. If you remove the load after device is in PLAY mode there should not be any issues.

On the Background section:
The channel with the open load will be seen by the DC Load diagnostics as an open load. They will continue to run on this channel until the power is removed or the DC Load diagnostics is aborted. I suggest that if the channel is open, they should abort the DC load diagnostic and never place this channel into play mode. Their software needs to be smart enough to know this.

Regards,
Gregg Scott

0 Jacob Wellnhofer over 2 years ago in reply to Gregg Scott

Prodigy 110 points

Hi,

the question was probably not phrased very well, sorry.
We wanted to know whether there are any concerns about DC diagnosis, PLAY-state, or MUTE-state for output channels which do not even have output filters populated for a short while (say less than 5s) on every startup. In these cases the PWM on the outputs may be active while there is neither filter, nor load on the device.
E.g., are there any risks about damaging the device or about its longevity in such a case?

BR,
Jacob

0 Gregg Scott over 2 years ago in reply to Jacob Wellnhofer

TI__Mastermind 45035 points

Hi Jacob,

We do not see any concerns. The DC Diagnosis will not allow the channel to turn on if there is no load. You must have the Bootstrap capacitors in place.

Regards,
Gregg Scott

+1 Jacob Wellnhofer over 2 years ago in reply to Gregg Scott

Prodigy 110 points

Ok, thanks for the info.

BR,

Jacob

0 Jacob Wellnhofer over 2 years ago in reply to Gregg Scott

Prodigy 110 points

Does this mean that in case there are no bootstrap capacitors you would advise against leaving the Hi-Z state?
BR,
Jacob

0 Gregg Scott over 2 years ago in reply to Jacob Wellnhofer

TI__Mastermind 45035 points

If you are able to get the device to get out of hi-Z mode without bootstrap capacitors, you will have an overcurrent event. It will have a fault immediately. Do not do it without bootstrap caps.

Regards,
Gregg Scott

0 Jacob Wellnhofer over 2 years ago in reply to Gregg Scott

Prodigy 110 points

Ok, understood. Thanks for the clarification!
BR,
Jacob

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TAS6424-Q1: Operating without load