Sve i svašta

[mikikg]

<p>Posto je bilo vise puta postavljano pitanje oko toga da li je bolja naponska (VFB) ili strujna (CFB) povratna veza kod pojacivaca, evo svez clanak oko toga koji objasnjava zasta je koja postavka zgodnija:</p>
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<p>[attachment=3143:7651.soufiane%201.png]</p>
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<p><a href="http://e2e.ti.com/blogs_/b/analogwire/archive/2013/06/26/how-to-determine-if-a-cfa-or-a-vfa-is-better-for-your-design.aspx?HQS=hpa_analogwirecfa_130714&amp;DCMP=mytinwsltr_07_20_2013&amp;sp_rid_pod3=LTIyMzU1NDY5NTkS1&amp;sp_mid_pod3=4968551">http://e2e.ti.com/blogs_/b/analogwire/archive/2013/06/26/how-to-determine-if-a-cfa-or-a-vfa-is-better-for-your-design.aspx?HQS=hpa_analogwirecfa_130714&amp;DCMP=mytinwsltr_07_20_2013&amp;sp_rid_pod3=LTIyMzU1NDY5NTkS1&amp;sp_mid_pod3=4968551</a></p>
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<p>A postoji i kombinacija "kompozitnih pojacivaca" koja daje prednosti iz obe postavke:</p>
<p><a href="http://www.ti.com/litv/pdf/sboa002">http://www.ti.com/litv/pdf/sboa002</a></p>
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<blockquote class="ipsBlockquote">
<p>To conclude, CFB is not meant for every application.&nbsp; They fit best in applications that are most affected by increase in noise gain and where limited BW (a few 100MHz) but where high gain is needed.&nbsp; The CFB most likely is not used as the front-end amplifier as the VFB tends to do better due to lower noise. But as a second stage, they do offer a much better BW to quiescent current ratio than any VFB.&nbsp; CFB also does better in summing application where several inputs are required.&nbsp; In such applications, VFB’s BW will be limited by the noise gain.&nbsp; The last application in which CFB is most useful is line driver, where typically high gain and high BW are required simultaneously but also have high output current and high slew rate.</p>
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