Return-Path: Received: from mtain-me11.r1000.mx.aol.com (mtain-me11.r1000.mx.aol.com [172.29.96.147]) by air-ma02.mail.aol.com (v129.4) with ESMTP id MAILINMA021-b4f34d25917133d; Thu, 06 Jan 2011 04:54:57 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-me11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 1123D380000DB; Thu, 6 Jan 2011 04:54:54 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PamXU-0004oS-5F for rs_out_1@blacksheep.org; Thu, 06 Jan 2011 09:53:48 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PamXT-0004oJ-Li for rsgb_lf_group@blacksheep.org; Thu, 06 Jan 2011 09:53:47 +0000 Received: from cavuit01.kulnet.kuleuven.be ([134.58.240.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PamXR-00020E-A3 for rsgb_lf_group@blacksheep.org; Thu, 06 Jan 2011 09:53:47 +0000 Received: from smtps01.kuleuven.be (smtpshost01.kulnet.kuleuven.be [134.58.240.74]) by cavuit01.kulnet.kuleuven.be (Postfix) with ESMTP id 788C97B8048 for ; Thu, 6 Jan 2011 10:53:36 +0100 (CET) Received: from ICTS-S-HUB-N4.luna.kuleuven.be (icts-s-hub-n4.luna.kuleuven.be [10.112.9.14]) by smtps01.kuleuven.be (Postfix) with ESMTP id 3161F31E705 for ; Thu, 6 Jan 2011 10:53:36 +0100 (CET) Received: from ICTS-S-EXC2-CA.luna.kuleuven.be ([10.112.11.13]) by ICTS-S-HUB-N4.luna.kuleuven.be ([10.112.9.14]) with mapi; Thu, 6 Jan 2011 10:53:36 +0100 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Date: Thu, 6 Jan 2011 10:53:36 +0100 Thread-Topic: 500kHz Classe-E Thread-Index: AcuthJnbEnwxwVETTFu373Lkx5OgawAAb8AM Message-ID: References: In-Reply-To: Accept-Language: nl-NL, nl-BE Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: nl-NL, nl-BE MIME-Version: 1.0 X-KULeuven-Information: Katholieke Universiteit Leuven X-KULeuven-Scanned: Found to be clean X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: RE: 500kHz Classe-E Content-Type: multipart/alternative; boundary="_000_BF4A524700075746A6467658DFC7102C88715AE9F5ICTSSEXC2CAlu_" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, TO_ADDRESS_EQ_REAL autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1d60934d25916e5043 X-AOL-IP: 195.171.43.25 X-Mailer: Unknown (No Version) --_000_BF4A524700075746A6467658DFC7102C88715AE9F5ICTSSEXC2CAlu_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Andy, what you got looks fine for a 500W PA. Just the on-resistance of the IRFP452 (0.4 Ohm) seems a bit high. At 10A= the heat loss in the FET will be 40W, lowering the efficiency a bit. An= option would be 2 devices in parallel (if the switching characteristics= do not differ too much) or better running from a higher voltage (80 to 10= 0V). I have build a 400W class E PA for 137kHz many years ago and it worked fin= e ... as long as the load was more or less 50 Ohm. I found that the class= E PA was much more sensitive to load mismatch than a push-pull class D PA= (G3YXM design). So I decided to stick to the last, sacrificing some effic= iency (85% for the class D PA, 93% for the class E PA if I remember well). 73, Rik ON7YD - OR7T ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.or= g] namens Andy Talbot [andy.g4jnt@gmail.com] Verzonden: donderdag 6 januari 2011 10:29 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: 500kHz Classe-E As I have all the bits available as surplus junk on the shelves, thought= I would put together a QRO class-E PA based around Alan's spreadsheet,= (with mod for matching built in). But before comitting to any particular power level / supply voltgage combi= nation thought I'd ask what others have reliably achieved with a similar= setup. Starting parameters : Supply voltage anything from 28 - 55V adjustable. 25 A max PA device - IRFP452 (have a small handful, so can allow a few to go po= p) Rated 500V, 0.4 Rdson, 14A, 190 Watts Drive, accurate 50% square wave from ICL7667 Resonant Inductor - air wound with 2mm Litz wire. I reckon that at 55V 500 Watts might be a value to aim for with a single= device, with the option to back off by lowering Vsupply. But before committing to winding inductors and making parallel combination= of high voltage caps, does anyone have any practical experience? Am I= aiming for too high a power perhaps. Andy www.g4jnt.com --_000_BF4A524700075746A6467658DFC7102C88715AE9F5ICTSSEXC2CAlu_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Andy,
 
what you got looks fine for a 500W= PA.
Just the on-resistance of the IRFP45= 2 (0.4 Ohm) seems a bit high. At 10A the heat loss in the FET will be 40W,= lowering the efficiency a bit. An option would be 2 devices in parallel= (if the switching characteristics do not differ too much) or better running from a higher voltage (80 to 100V).
I have build a 400W class E PA for= 137kHz many years ago and it worked fine ... as long as the load was more= or less 50 Ohm. I found that the class E PA was much more sensitive to lo= ad mismatch than a push-pull class D PA (G3YXM design). So I decided to stick to the last, sacrificing some efficiency= (85% for the class D PA, 93% for the class E PA if I remember well).
 
73, Rik  ON7YD - OR7T
 
Van: owner-rsgb_= lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Andy= Talbot [andy.g4jnt@gmail.com]
Verzonden: donderdag 6 januari 2011 10:29
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: LF: 500kHz Classe-E

As I have all the bits available as surplus junk on the shelves, thou= ght I would put together a QRO class-E  PA based around Alan's spread= sheet, (with mod for matching built in).
But before comitting to any particular power level / supply voltgage= combination thought I'd ask what others have reliably achieved with a sim= ilar setup.
 
Starting parameters :
   Supply voltage anything from 28 - 55V adjustable. = 25 A max
   PA device  - IRFP452 (have a small handful, so can= allow a few to go pop)  Rated 500V,   0.4 Rdson, 14A, &nbs= p;190 Watts
   Drive, accurate 50% square wave from ICL7667
   Resonant Inductor -  air wound with 2mm Litz= wire.
 
I reckon that at 55V 500 Watts might be a value to aim for with a sin= gle device, with the option to back off by lowering Vsupply.
But before committing to winding inductors and making parallel= combination of high voltage caps, does anyone have any practical experien= ce?   Am I aiming for too high a power perhaps.
 
Andy
 
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