Return-Path: X-Spam-DCC: paranoid 1233; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,HTML_TINY_FONT autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u1MIjD47006295 for ; Mon, 22 Feb 2016 19:45:13 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aXvQc-0005zh-Ba for rs_out_1@blacksheep.org; Mon, 22 Feb 2016 18:41:50 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aXvQb-0005zX-Tr for rsgb_lf_group@blacksheep.org; Mon, 22 Feb 2016 18:41:49 +0000 Received: from mail-wm0-f41.google.com ([74.125.82.41]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1aXvPa-0007SW-6V for rsgb_lf_group@blacksheep.org; Mon, 22 Feb 2016 18:41:48 +0000 Received: by mail-wm0-f41.google.com with SMTP id g62so187433601wme.1 for ; Mon, 22 Feb 2016 10:40:31 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=HIHTci6ah7hFoOAMjHglPvyy61M7K2vQsZor3TjgDo0=; b=QRWnzlrZ6/T6XJij6Ma5PAJAwrkdt1ZIwIcidiJBH53T8RQ7X/2FiaxkiaFv21kILF h6zERGQETvO7PfoBeAKZHcT5mGPVzMI5vxVwlo4NwoIGjSCkMDV98hw9rHbHuxmBwjQK qsF02MAGkg2K7PQiFdVzoZCY7ea5oH+IPOc4BmQ0TUSR/y1FaId8DkUtQ9UZbbKoJVE3 uFcVDLqZxWSwU6ICnqa1WNzB2lPpL2YRRJlOsw0J8r6HuptCKTDw2Ooy6fY6v84NoUGe 6P63+W1ZNl9V5ApWpzJrqwQJFRFlLZOrGRUySHtkDfrBIPj9ornFLkxfRIiFS5tjKRtP kXDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=HIHTci6ah7hFoOAMjHglPvyy61M7K2vQsZor3TjgDo0=; b=Txpxo9n5iDw7ycKd3vBk0o2upQYUaBpvdoI4kwkvPgaPBShSnPksgA3lH/iAwBdaTP a558Nm+XydiKvfZ1xt8M5gyTGupFi9+rLwYlBnFQRWt2NbJQZ30z8hPJ/+du1vB3NWno 813uVAIDwShJLBr2qS5Sxa4vQtvqKPjYsfRMyZ2b1YgELkODMaykTToswC4fHzrfjoUv PVjS1A3EA1p9dfEcl01OohQKR77htYdcwB687b3J84rfLBmH47Q01u5ti5j8BGdKGAu5 ayFy9dyOcAUwd/9v0m2aMhVOXvylOZNTTGo7BQaPOyw97SWT/cFFRBRG0LyBZ4G+P0ia 79tQ== X-Gm-Message-State: AG10YOSrdQbcnCdhNLr5+yEjYQEFtCzJi0paG+3lCy3gzpljJP7ldvikY1Ej5IFyFvSYZ+fEDIzGgmBZmLyIDg== MIME-Version: 1.0 X-Received: by 10.194.113.130 with SMTP id iy2mr14608948wjb.56.1456166386361; Mon, 22 Feb 2016 10:39:46 -0800 (PST) Received: by 10.28.187.213 with HTTP; Mon, 22 Feb 2016 10:39:46 -0800 (PST) In-Reply-To: <7E7DFBB4D102A04DB5ADC88D66628A4A444D7A4A@ICTS-S-MBX1.luna.kuleuven.be> References: <7E7DFBB4D102A04DB5ADC88D66628A4A444D7A4A@ICTS-S-MBX1.luna.kuleuven.be> Date: Mon, 22 Feb 2016 18:39:46 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@yahoogroups.co.uk Cc: "rsgb_lf_group@blacksheep.org" X-Scan-Signature: 588071ad363eff79fc1a170bd98c0eea Subject: LF: Re: [rsgb_lf_group] Single Stage Class-B Content-Type: multipart/alternative; boundary=001a1130cffc3175d9052c602833 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 6942 --001a1130cffc3175d9052c602833 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable There's nothing inherently "more linear" about push pull over a single stage, given you run the same device at the same power per stage (ie half the PP level) 'jnt On 22 February 2016 at 18:34, Rik Strobbe rik.strobbe@fys.kuleuven.be [rsgb_lf_group] wrote: > > > Hello Andy, > > > > the advantage of a push-pull class B amplifier is that it it pretty linea= r > at higher power levels. > > > > 73, Rik ON7YD - OR7T > > > ------------------------------ > *Van:* rsgb_lf_group@yahoogroups.co.uk [rsgb_lf_group@yahoogroups.co.uk] > *Verzonden:* maandag 22 februari 2016 18:31 > *Aan:* rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk > *Onderwerp:* [rsgb_lf_group] Single Stage Class-B > > > > Whilst out walking and pondering, as one does.... > > There are hundreds of designs out there for linear power amps using > FETS. They all use a similar design, push-pull with centre tapped ferrit= e > cored transformers at input and output, often with resistive feedback - a= nd > all broadband. The design is so standard it's become tedious ... and as= I > don't do tedious, it made me think: > > Back in days of yore when those big bottles ruled the roost , apart from > a few designs for UHF, they were all single ended. > > So, why not a single ended MOSFET amp (for single band operation)? We'r= e > used to seeing single device for class-E, where the tank circuit does mu= ch > of the waveform cleaning, and reduces the low pass filter requirements. > So what's wrong with a tank-based design for class-B? > > A single ended amp can even be made ferrite free (although a final > stage DC feed choke would no doubt benefit from it). Apart from a few > very low power designs, I don't recall seeing any designs for single band > ferrite free linear amps using power MOSFETS. > Only major downsides I visualise is that load resistance at the device is > 4 times lower for the same Vdd and Pout , and device dissipation is doubl= ed > > Has no one ever bothered, because broadband transformer push-pull is so > straightforward? > Has a trick been missed? > > Andy G4JNT > > > __._,_.___ > ------------------------------ > Posted by: Rik Strobbe > ------------------------------ > Reply via web post > > =E2=80=A2 Reply to sender > > =E2=80=A2 Reply to group > > =E2=80=A2 Start a new topic > > =E2=80=A2 Messages in this topic > > (2) > Visit Your Group > > > > [image: Yahoo! Groups] > > =E2=80=A2 Privacy =E2=80=A2 > Unsubscribe > =E2= =80=A2 Terms > of Use > > . > > __,_._,___ > --001a1130cffc3175d9052c602833 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
There's nothing inherently "more linear"= ; about push pull over a single stage, given you run the same device at the= same power per stage (ie half the PP level)=C2=A0=C2=A0=C2=A0=C2=A0
<= div>
'jnt


On 22 February 2016 at 18:34, Rik Stro= bbe rik.strobbe@fys.kuleuven= .be [rsgb_lf_group] <rsgb_lf_group@yahoogroups.co.uk= > wrote:
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=C2=A0
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Hello Andy,

=C2=A0

the advantage of a push-pull class B amplifier is that it it pretty line= ar at higher power levels.

=C2=A0

73, Rik=C2=A0 ON7YD - OR7T

=C2=A0

Van: rsgb_lf_group@yahoogroups.co.uk [rsgb_lf_group@yahoogroups.co.uk= ]
Verzonden: maandag 22 februari 2016 18:31
Aan: rsgb_lf_group@blacksheep.org; rsgb_lf_group@yahoogroups.co.uk
Onderwerp: [rsgb_lf_group] Single Stage Class-B

=C2=A0

Whilst out walking and pondering, as one does....

There are hundreds of designs out there for =C2=A0linear=C2=A0power am= ps=C2=A0using FETS.=C2=A0 They all use a similar design,=C2=A0push-pull wit= h centre tapped ferrite cored transformers at input and output, often with = resistive feedback - and all broadband.=C2=A0=C2=A0 The design is so standard it's become tedious ... and=C2=A0as I don't=C2=A0do tedio= us, it made me think:

Back in days of yore when those big bottles ruled the roost ,=C2=A0 ap= art from a few designs for UHF, they were all single ended.

So, why not a single ended MOSFET amp (for single band operation)?=C2= =A0=C2=A0 We're used to seeing=C2=A0single=C2=A0device=C2=A0=C2=A0for c= lass-E, where the tank circuit does much of the waveform cleaning, and redu= ces the=C2=A0low pass filter requirements.=C2=A0=C2=A0=C2=A0 So what's = wrong with a tank-based =C2=A0design for class-B?

A single ended=C2=A0amp can even be made ferrite free (although=C2=A0a= final stage=C2=A0DC feed choke would no doubt benefit from it).=C2=A0=C2= =A0 Apart from a few very low power designs, I don't recall seeing any = designs for single band ferrite free linear amps using power MOSFETS.=C2=A0
Only major downsides=C2=A0I=C2=A0visualise is that=C2=A0load resistanc= e at the device is 4 times lower for the same Vdd and Pout , and device dis= sipation is doubled

Has no one ever bothered, because broadband transformer push-pull is s= o straightforward?
Has a trick been missed?=C2=A0=C2=A0

Andy=C2=A0 G4JNT


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__._,_.___
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Posted by: Rik Strobbe <rik.strobbe@fys.kuleuven.be>
Repl= y via web post =E2=80=A2 Reply to sender =E2=80=A2 Reply to group =E2=80=A2 Start a new topic =E2=80=A2 Messages in this topic (2)
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3D"Yahoo!
=E2=80=A2 Privacy =E2=80=A2 Unsubscribe =E2=80=A2 Terms of Use

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