New Class D design

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Eva

Eva

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Joined 2003
Hey, but look at the schematics, they have migrated to a phase-shifted self oscillating arrangement, in such a way that modifying it for post-filter feedback is trivial.

What they have done at IR is essentially a single-chip UcD solution :D:D It only lacks the balanced inputs...
 
Ouroboros

Ouroboros

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Joined 2003
I've been looking at the IRS2092 data (as published so far) to see if it could be used to implement a UCD-style circuit. The input op-amp is internally coupled to the comparator stage, which is unfortunate, but the input op-amp is a transconductance amplifier, so it might just be possible to couple in the feedback to the op-amp/comparator junction to get a phase-shift 'UCD' style self-oscillator.

I've got a chap coming in to see me from 'Future Electronics' (A big UK distributor) tomorrow about this chip, so I'll try to scrounge a few parts to try it out.
 
Ouroboros

Ouroboros

Member
Joined 2003
Hello Ivan. Yes the fact that the comparator isn't differential is an issue. I've not had the time to study the chip yet, but at a glance it seems that to apply UCD style feedback directly into the input of the comparator would require that the feedback went to the + input of the comparator (which isn't accessible).
 
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