Comments on: Class-D Hi-Fi amplifier for automotive audio

By: Alun Williams

Alun Williams — Thu, 04 Mar 2021 10:50:38 +0000

In reply to Steve Bush. Indeed, as you correctly say, the control theory gurus have waived their wands, and done the hard yards of maths and analysis :-)

By: Steve Bush

Steve Bush — Thu, 04 Mar 2021 09:30:23 +0000

In reply to Steve Kurt.

Good morning Mr Kurt
Apologies to you: I realised I failed a bit in my wording there and have improved it now (I claim!), the mystery was over the maximum operating voltage.
The information I got did indeed mention cranking for the low voltage end, so you are spot-on 🙂
I wonder if it would not be fairer for the poor battery if the sound system stopped at about 8V, as anything below that means something important is desperately in need of power. Interesting chip, I thought. I can remember when folks were wondering how to get the output filter inside the DAC loop, now quite a few companies are doing it – the control theory gurus have waived their wands.

By: Steve Kurt

Steve Kurt — Thu, 04 Mar 2021 01:20:22 +0000

re:”Supply voltage is a bit of a mystery: minimum is 4.5V, although this is operating and for turn-on it has to be 5V or greater”.
Just a guess… this might be related to the need to operate (i.e. keep the logic running) during engine cranking. This guess is based on analogous experience with earth moving machines, and you’d need to find someone familiar with automotive standards to have more confidence.

Editor’s note: Mea culpa, my wording in the article was poor and has now been improved. I meant the mystery to apply to the oddly-specified upper working voltage.