Return-Path: Received: (qmail 29014 invoked from network); 2 Aug 1999 23:35:25 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 2 Aug 1999 23:35:25 +0100 Received: (qmail 14069 invoked from network); 2 Aug 1999 22:38:17 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 2 Aug 1999 22:38:17 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11BQYR-0004v3-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 02 Aug 1999 23:27:35 +0100 X-Priority: 3 Received: from nms.rz.uni-kiel.de ([134.245.1.2]) by post.thorcom.com with smtp (Exim 3.02 #1) id 11BQYQ-0004uj-00 for rsgb_lf_group@blacksheep.org; Mon, 02 Aug 1999 23:27:34 +0100 X-MSMail-Priority: Normal Received: from srv1.mail.uni-kiel.de by nms.rz.uni-kiel.de with Local-SMTP (PP); Tue, 3 Aug 1999 00:27:29 +0200 Received: from nephro.uni-kiel.de (PC108144.dial.uni-kiel.de [134.245.108.144]) by srv1.mail.uni-kiel.de (8.9.1b+Sun/8.9.1) with ESMTP id AAA12807 for ; Tue, 3 Aug 1999 00:27:41 +0200 (MET DST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: <37A61B4B.E9BC05A@nephro.uni-kiel.de> Date: Tue, 03 Aug 1999 00:27:23 +0200 From: "Peter W. Schnoor" Organization: University of Kiel, Clinic of Nephrology X-Mailer: Mozilla 4.05 [en] (X11; I; Linux 2.0.33 i586) To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: Class E RF amplifiers References: <002001bedcc7$179cb0a0$fc96b38f@w8k3f0> <3.0.1.16.19990802173940.2ff70aec@mail.cc.kuleuven.ac.be> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: Hello, Rik Strobbe wrote: > I am using a 'G3YXM' PA, slightly modified from the original. Main changes > are a pair of IRFP350's on each side of the push-pull (running at 56V) and > an extra LC section in the LPF. > With 9.2A draincurrent (= 515W input) I get 2.95A RF current into my 52 Ohm > dummyload (= 452W output). That means 87.8% efficiency. > Seems to be within the range of this famous 'Class E'. It's a classical "class-D" design, i.e. a switched pp-amplifier reaching very high efficiency but much more complicated than class-E. Running class-D means that most dissipation occurs at switching time. Class-E is able to avoid dissipation even at switching. The key is to load an amplifier capacitively such that (MosFet) Ud *and* dUd/dt at switchig time are both zero (soft landing). Theoretically (!) you will have no dissipation at all... 54°16'N / 10°04'E, JO54ag 73 es gl de Peter, DF3LP