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<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-family:Wingdings"><span style="mso-list:Ignore">Ø<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]>But Class D amps are analog, right? :-)<o:p></o:p></p>
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<p class="MsoNormal">Mine aren’t ! STM32F730 MCU driving an IRF2003 driving pairs of paralleled n type power MOSFETs (I use F20N60s). Voltages might vary but most definitely ON or OFF :-)<o:p></o:p></p>
<p class="MsoNormal">A small calibration signal is taken back to the STM32’s A-D to model the output stage behaviour, but this isn’t used in real time, i.e. no negative feedback.<o:p></o:p></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Synth-diy [mailto:synth-diy-bounces@synth-diy.org]
<b>On Behalf Of </b>Mattias Rickardsson<br>
<b>Sent:</b> 14 January 2022 20:35<br>
<b>To:</b> Synth DIY<br>
<b>Subject:</b> Re: [sdiy] Low voltage synthesis?<o:p></o:p></span></p>
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<p class="MsoNormal">cheater cheater via Synth-diy <<a href="mailto:synth-diy@synth-diy.org">synth-diy@synth-diy.org</a>> skrev:<o:p></o:p></p>
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<p class="MsoNormal"> I wonder what's being used in places like<br>
mobile phones or wireless earbuds for example, they can't be running<br>
+/-5V op amps or LV op amps with major crossover distortion.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I've used some mobile codec from Dialog to pump up the jam in a low-voltage application with mainly positive supplies, check out their stuff for some typical insight.<o:p></o:p></p>
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<p class="MsoNormal">Mike Bryant <<a href="mailto:mbryant@futurehorizons.com">mbryant@futurehorizons.com</a>> skrev:<o:p></o:p></p>
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<p class="MsoNormal">Nowadays mobile phone amplifiers are all digital - the digital audio (I2S possibly) digital signal is converted to a PDM signal which drives a class D amplifier and a simple LC reconstruction filter on the output.<br>
Some years ago they did use DACs (e.g. Wolfson devices) followed by a Class D amp, until someone realised going digital -> analogue -> digital -> analogue was a nonsense.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">But Class D amps are analog, right? :-)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">/mr<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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