Inductive digital isolator

Hi all,
The reason for this post is that I want to safeguard my idea from any  
patenting attempts. Releasing the details to the public domain should do  
the trick, so here they are:

Imagine a transformer built from two coils routed on a PCB on two  
different layers (top and bottom for example). The thickness of the PCB  
provides the isolation required. Transmission is performed by shorting one  
coil, forming a closed loop - one end is grounded, the other connected to  
a microcontroller pin. The micro grounds the pin and that's one state.  
When the micro puts the pin in high impedance, the other state is  
transmitted. A micro on the other side measures the inductance of the  
other (coupled) coil. By observing a variation in inductance it can tell  
if the coil on the other side is shorted or not.

Should anyone be interested, I have it implemented. We do this on  
Microchip's microcontrollers and measure the inductance with the CTMU  
hardware peripheral. Works at 80kbps full-duplex on a PIC24F. I have  
written an application note and posted it on my company website. We call  
the thing "Freesolator", since it requires almost no components (one  
resistor, once you have CTMU on board). We have demo boards and can make  
the source code available. See http://protronik.pl/freesolator-en.html

Hope you don't find this post too spammy. I couldn't think of a better  
method of undeniable disclosure.

Cheers,
Andrzej Ekiert

Andrzej Ekiert wrote:
> Hi all,
> The reason for this post is that I want to safeguard my idea from any
> patenting attempts. Releasing the details to the public domain should do
> the trick, so here they are:
> 
> Imagine a transformer built from two coils routed on a PCB on two
> different layers (top and bottom for example). The thickness of the PCB
> provides the isolation required. Transmission is performed by shorting
> one coil, forming a closed loop - one end is grounded, the other
> connected to a microcontroller pin. The micro grounds the pin and that's
> one state. When the micro puts the pin in high impedance, the other
> state is transmitted. A micro on the other side measures the inductance
> of the other (coupled) coil. By observing a variation in inductance it
> can tell if the coil on the other side is shorted or not.
> 
> Should anyone be interested, I have it implemented. We do this on
> Microchip's microcontrollers and measure the inductance with the CTMU
> hardware peripheral. Works at 80kbps full-duplex on a PIC24F. I have
> written an application note and posted it on my company website. We call
> the thing "Freesolator", since it requires almost no components (one
> resistor, once you have CTMU on board). We have demo boards and can make
> the source code available. See http://protronik.pl/freesolator-en.html
> 
> Hope you don't find this post too spammy. I couldn't think of a better
> method of undeniable disclosure.
> 

Looks like you have re-invented the inductive proximity sensor :-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

Dnia 25-09-2012 o 00:17:39 Joerg <invalid@invalid.invalid> napisa=C5=82(=
a):

> Looks like you have re-invented the inductive proximity sensor :-)
>

Well, there were other inspirations as well. But the application area ma=
y  =

also matter - I don't think this was a known method for data transmissio=
n,  =

so it might have been patentable. Now it surely isn't ;-)

ae

On Tue, 25 Sep 2012 00:31:19 +0200, "Andrzej Ekiert"
<dspicant@tlen.pl> wrote:

>Dnia 25-09-2012 o 00:17:39 Joerg <invalid@invalid.invalid> napisa?(a):
>
>> Looks like you have re-invented the inductive proximity sensor :-)
>>
>
>Well, there were other inspirations as well. But the application area may  
>also matter - I don't think this was a known method for data transmission,  
>so it might have been patentable. Now it surely isn't ;-)
>
>ae

My method as well... keep it _art_, but _privately_ documented.

I'm expert witness in a case right now where a heathen patented a
block diagram... science fiction, then is suing now that technology
has caught up with fiction :-(
		
                                        ...Jim Thompson
-- 
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Andrzej Ekiert wrote:

> Hi all,
> The reason for this post is that I want to safeguard my idea from any  
> patenting attempts. Releasing the details to the public domain should 
> do  the trick, so here they are:
> 
> Imagine a transformer built from two coils routed on a PCB on two  
> different layers (top and bottom for example). The thickness of the PCB  
> provides the isolation required. Transmission is performed by shorting 
> one  coil, forming a closed loop - one end is grounded, the other 
> connected to  a microcontroller pin. The micro grounds the pin and 
> that's one state.  When the micro puts the pin in high impedance, the 
> other state is  transmitted. A micro on the other side measures the 
> inductance of the  other (coupled) coil. By observing a variation in 
> inductance it can tell  if the coil on the other side is shorted or not.
> 
> Should anyone be interested, I have it implemented. We do this on  
> Microchip's microcontrollers and measure the inductance with the CTMU  
> hardware peripheral. Works at 80kbps full-duplex on a PIC24F. I have  
> written an application note and posted it on my company website. We 
> call  the thing "Freesolator", since it requires almost no components 
> (one  resistor, once you have CTMU on board). We have demo boards and 
> can make  the source code available. See 
> http://protronik.pl/freesolator-en.html
> 
> Hope you don't find this post too spammy. I couldn't think of a better  
> method of undeniable disclosure.
> 
> Cheers,
> Andrzej Ekiert
you're too late! way to late.

Jamie

"Andrzej Ekiert" <dspicant@tlen.pl> wrote in
news:op.wk5ufqawf6rg9m@jabba.lan: 

> Hi all,
> The reason for this post is that I want to safeguard my idea from any 
> patenting attempts. Releasing the details to the public domain should
> do  the trick, so here they are:
> 
> Imagine a transformer built from two coils routed on a PCB on two  
> different layers (top and bottom for example). The thickness of the
> PCB  provides the isolation required. Transmission is performed by
> shorting one  coil, forming a closed loop - one end is grounded, the
> other connected to  a microcontroller pin. The micro grounds the pin
> and that's one state.  When the micro puts the pin in high impedance,
> the other state is  transmitted. A micro on the other side measures
> the inductance of the  other (coupled) coil. By observing a variation
> in inductance it can tell  if the coil on the other side is shorted or
> not. 
> 
> Should anyone be interested, I have it implemented. We do this on  
> Microchip's microcontrollers and measure the inductance with the CTMU 
> hardware peripheral. Works at 80kbps full-duplex on a PIC24F. I have  
> written an application note and posted it on my company website. We
> call  the thing "Freesolator", since it requires almost no components
> (one  resistor, once you have CTMU on board). We have demo boards and
> can make  the source code available. See
> http://protronik.pl/freesolator-en.html 
> 
> Hope you don't find this post too spammy. I couldn't think of a better
>  method of undeniable disclosure.
> 
> Cheers,
> Andrzej Ekiert
> 
Use an ethernet isolation transformer, they come in very small
footprints and are made for the purpose
(datatransmission with isolated in/out).

"Sjouke Burry" <s@b> wrote in message 
news:XnsA0D92526C1FBEsjoukeburrysoesterbe@213.75.12.10...
> Use an ethernet isolation transformer, they come in very small
> footprints and are made for the purpose
> (datatransmission with isolated in/out).

Not nearly as much isolation as FR-4, though -- certainly not reinforced. 
With that kind of isolation, you can drive IGBTs on any supply with 
impugnity.

Tim

-- 
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms 

Jim Thompson wrote:
> On Tue, 25 Sep 2012 00:31:19 +0200, "Andrzej Ekiert"
> <dspicant@tlen.pl>  wrote:
>
>> Dnia 25-09-2012 o 00:17:39 Joerg<invalid@invalid.invalid>  napisa?(a):
>>
>>> Looks like you have re-invented the inductive proximity sensor :-)
>>>
>>
>> Well, there were other inspirations as well. But the application area may
>> also matter - I don't think this was a known method for data transmission,
>> so it might have been patentable. Now it surely isn't ;-)
>>
>> ae
>
> My method as well... keep it _art_, but _privately_ documented.
>
> I'm expert witness in a case right now where a heathen patented a
> block diagram... science fiction, then is suing now that technology
> has caught up with fiction :-(
> 		
>                                          ...Jim Thompson
   To the best of my knowledge, one cannot patent a block diagram - not 
even as a design patent.
   And design patents are essentially worthless since one minor aspect 
can be changed to generate a new design patent.
   Crudely put, the shape of a paper clip cannot be patented in a way to 
protect its use; change the wiggle or bend here to make a different 
design and thus create competition that cannot be negated by "interference".

On Tue, 25 Sep 2012 00:08:04 +0200, "Andrzej Ekiert"
<dspicant@tlen.pl> wrote:

>Hi all,
>The reason for this post is that I want to safeguard my idea from any  
>patenting attempts. Releasing the details to the public domain should do  
>the trick, so here they are:
>
>Imagine a transformer built from two coils routed on a PCB on two  
>different layers (top and bottom for example). The thickness of the PCB  
>provides the isolation required. Transmission is performed by shorting one  
>coil, forming a closed loop - one end is grounded, the other connected to  
>a microcontroller pin. The micro grounds the pin and that's one state.  
>When the micro puts the pin in high impedance, the other state is  
>transmitted. A micro on the other side measures the inductance of the  
>other (coupled) coil. By observing a variation in inductance it can tell  
>if the coil on the other side is shorted or not.
>
>Should anyone be interested, I have it implemented. We do this on  
>Microchip's microcontrollers and measure the inductance with the CTMU  
>hardware peripheral. Works at 80kbps full-duplex on a PIC24F. I have  
>written an application note and posted it on my company website. We call  
>the thing "Freesolator", since it requires almost no components (one  
>resistor, once you have CTMU on board). We have demo boards and can make  
>the source code available. See http://protronik.pl/freesolator-en.html
>
>Hope you don't find this post too spammy. I couldn't think of a better  
>method of undeniable disclosure.
>
>Cheers,
>Andrzej Ekiert


You could put an LED on one side of the board and a photodiode on the
other. Punch a hole in any power/ground planes to let the light
through the FR4.




-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

On 9/24/2012 9:29 PM, Robert Baer wrote:
> Jim Thompson wrote:
>> On Tue, 25 Sep 2012 00:31:19 +0200, "Andrzej Ekiert"
>> <dspicant@tlen.pl>  wrote:
>>
>>> Dnia 25-09-2012 o 00:17:39 Joerg<invalid@invalid.invalid>  napisa?(a):
>>>
>>>> Looks like you have re-invented the inductive proximity sensor :-)
>>>>
>>>
>>> Well, there were other inspirations as well. But the application area
>>> may
>>> also matter - I don't think this was a known method for data
>>> transmission,
>>> so it might have been patentable. Now it surely isn't ;-)
>>>
>>> ae
>>
>> My method as well... keep it _art_, but _privately_ documented.
>>
>> I'm expert witness in a case right now where a heathen patented a
>> block diagram... science fiction, then is suing now that technology
>> has caught up with fiction :-(
>>
>>                                          ...Jim Thompson
>    To the best of my knowledge, one cannot patent a block diagram - not
> even as a design patent.
>    And design patents are essentially worthless since one minor aspect
> can be changed to generate a new design patent.
>    Crudely put, the shape of a paper clip cannot be patented in a way to
> protect its use; change the wiggle or bend here to make a different
> design and thus create competition that cannot be negated by
> "interference".
>

The only thing that matters in the patent is the "claims" section.

Incidentally, if you don't want someone to patent an idea but rather 
have it open source, just patent it yourself and don't enforce the 
patent. There is no better prior art than a patent with that prior art.