Message-ID: <58F63C48.4020006@posteo.de>
Date: Tue, 18 Apr 2017 18:18:16 +0200
From: DK7FC <selberdenken@posteo.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <15b72b3360e.marcocadeddu@tin.it> <731997437.20170416124847@gmail.com> <58F525B4.9090008@posteo.de> <1229336941.20170418125840@gmail.com> <58F60567.20001@posteo.de>
In-Reply-To: <58F60567.20001@posteo.de>
Subject: LF: A transductor for power regulation?
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

Hi all,

I'm just thinking about transductors and find them them quite 
fascinating again. I read a bit Wikipedia and thought about the use as a 
steerable transformer.
Imagine you have a hard switching class D PA, H bridge or so. The output 
is a constant voltage source and it is no problem to connect no load, as 
long as a proper type of low pass filter is used.
Then imagine a simple 1:1 ferrite transformer, 50 Ohm to 50 Ohm. The 
transformer has a 3rd winding for a DC current (to compensate the AC 
component transformed from the RF windings, 2 cores must be used, which 
are in parallel for the RF and anti-serial for DC).
Then i can saturate the transformer with the DC so the 皴 falls down to 1.
With this arrangement i could build a linear PA out of a switch mode PA, 
even a fast one, which avoids key-clicks, at least in QRSS-3 (you 
remember the mode) or OP32 or even EbNaut on LF?
Sounds like an interesting experiment at least. The question is how warm 
the transformer would become when the RF output current is permanently 
reduced to 50%.
Has someone ever tried that on LF/MF?

73, Stefan