Return-Path: Received: (qmail 51189 invoked from network); 21 Jan 2004 09:22:15 -0000 Received: from unknown (HELO ptb-mxscan03.plus.net) (212.159.14.237) by ptb-mailstore01.plus.net with SMTP; 21 Jan 2004 09:22:15 -0000 Received: (qmail 76016 invoked from network); 21 Jan 2004 09:22:15 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore03.plus.net (212.159.14.217) by ptb-mxscan03.plus.net with SMTP; 21 Jan 2004 09:22:14 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1AjEYv-000Jeu-WF for dave@picks.force9.co.uk; Wed, 21 Jan 2004 09:22:14 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AjEYL-0002Bu-E9 for rs_out@blacksheep.org; Wed, 21 Jan 2004 09:21:37 +0000 Received: from [130.244.199.131] (helo=fep03-svc.swip.net) by post.thorcom.com with esmtp (Exim 4.14) id 1AjEYK-0002Bl-EE for rsgb_lf_group@blacksheep.org; Wed, 21 Jan 2004 09:21:36 +0000 X-Fake-Domain: oemcomputer Received: from oemcomputer ([213.101.38.202]) by fep03-svc.swip.net with SMTP id <20040121092132.QTHI1748.fep03-svc.swip.net@oemcomputer> for ; Wed, 21 Jan 2004 10:21:32 +0100 X-Bad-Message-ID: no DNS (oemcomputer) Message-ID: <004801c3dfff$fd27bbc0$ca2665d5@oemcomputer> From: "Johan Bodin" To: rsgb_lf_group@blacksheep.org References: <1074543877.400c3d051a334@webmail2.kuleuven.be><5.1.0.14.0.20040120090129.0362e1d0@u0019445.kuleuven.be> <5.1.0.14.0.20040120155308.036a8a60@u0019445.kuleuven.be> <003d01c3dfa3$4766f960$2102000a@ibm> Date: Wed, 21 Jan 2004 10:20:33 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: LF: Re: TC44/MUR1660 question...thanks..... Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 2 Hello Dick and the group, there are many MOSFET drivers on the market. Some examples: Maxim MAX626/627/628 www.maxim-ic.com International Rectifier IR21xx / IR21xxx www.irf.com Intersil HIP408x, ICL7667 www.intersil.com Elantec EL7002/7012/7022 www.??? As Alan mentioned, a dedicated driver IC is not always necessary. The MOSFET gates can be adequately driven by a simple complementary transistor buffer unless extremely fast rise/fall times are required. > Probably my first experimental 137kHz set-up will be something > like the DF3LP "impatient design", simple straight in the old > fashioned way... It is equally easy to build a "true" class E amplifier which has many advantages. When properly tuned, it runs amazingly cool and class E is inherently free from "MOSFET killer" voltage spikes. The transistor current is very low at the switching instants so the drive waveform is not very important, it can be quite "non-square" (it should have 50% duty cycle though). Some HF class E designs even use sine wave drive! The only downside that I can think of is that the "transistor utilization factor" is quite low - less output power per transistor when compared to some other amplifier topologies such as class D. The reason is simply that the peak drain voltage in a class E amplifier is almost 4 * supply voltage... Jim Tonne has written a nice little program for class E design, CLASSE101.ZIP is available here: http://www.qsl.net/wb6bld/classe.html Also, have a look at SOKAL.ZIP on the same page. It contains a PDF paper with general information about class E. It was written by Nathan Sokal, "Mr Class E" himself :-) 73 Johan Bodin, SM6LKM