On Sunday, 2 October 2016 23:08:17 UTC+2, Klaus Kragelund wrote:
> On Saturday, October 1, 2016 at 6:13:30 PM UTC+2, Winfield Hill wrote:
> > Neon John wrote...
> > >
> > >On 30 Sep 2016 18:53:27 -0700, Winfield Hill
> > ><hill@rowland.harvard.edu> wrote:
> > >
> > >> An elegant idea, Paul. But the 20kHz bandwidth
> > >> is lacking. A current transformer does better
> > >> than that and is also isolated.
> > >
> > > I strongly suggest you take the advice of someone
> > > else in this thread and take a look at the Allegro
> > > hall effect sensors. Here's the one I use in my
> > > induction heaters. allegro-microsystems ACS758
> >
> > Thanks, John, I missed seeing that. I like the
> > serious look of the package, but I'm puzzled why
> > they don't offer one with leads prebent for SMT.
> > The 50A lowest FS range is an issue, with a 100mA
> > DC offset. But I guess many apps can figure out
> > their own specific offset.
> >
Normally you would do a offset nulling of the current sensor during power-up or regulary, since it has an offset voltage for 0A anyway
Cheers
Klaus
Reply by Klaus Kragelund●October 2, 20162016-10-02
On Saturday, October 1, 2016 at 6:13:30 PM UTC+2, Winfield Hill wrote:
> Neon John wrote...
> >
> >On 30 Sep 2016 18:53:27 -0700, Winfield Hill
> ><hill@rowland.harvard.edu> wrote:
> >
> >> An elegant idea, Paul. But the 20kHz bandwidth
> >> is lacking. A current transformer does better
> >> than that and is also isolated.
> >
> > I strongly suggest you take the advice of someone
> > else in this thread and take a look at the Allegro
> > hall effect sensors. Here's the one I use in my
> > induction heaters. allegro-microsystems ACS758
>
> Thanks, John, I missed seeing that. I like the
> serious look of the package, but I'm puzzled why
> they don't offer one with leads prebent for SMT.
> The 50A lowest FS range is an issue, with a 100mA
> DC offset. But I guess many apps can figure out
> their own specific offset.
>
"rickman" wrote in message news:nsoheo$u7k$1@dont-email.me...
> On 9/30/2016 9:53 PM, Winfield Hill wrote:
>> P E Schoen wrote...
>>
>>> You might also consider an analog Hall effect sensor you can glue to a
>>> PCB over a track. Less than a dollar:
>>> http://www.mouser.com/ProductDetail/Texas-Instruments/DRV5053EAQLPGM
>
>> An elegant idea, Paul. But the 20kHz bandwidth is lacking. A current
>> transformer does better than that and is also isolated.
> I think whether 20 kHz is limiting depends on your application.
> Transformers tend to be rather large compared to a TO-92.
>
>On 30 Sep 2016 18:53:27 -0700, Winfield Hill
><hill@rowland.harvard.edu> wrote:
>
>> An elegant idea, Paul. But the 20kHz bandwidth
>> is lacking. A current transformer does better
>> than that and is also isolated.
>
> I strongly suggest you take the advice of someone
> else in this thread and take a look at the Allegro
> hall effect sensors. Here's the one I use in my
> induction heaters. allegro-microsystems ACS758
Thanks, John, I missed seeing that. I like the
serious look of the package, but I'm puzzled why
they don't offer one with leads prebent for SMT.
The 50A lowest FS range is an issue, with a 100mA
DC offset. But I guess many apps can figure out
their own specific offset.
--
Thanks,
- Win
Reply by rickman●October 1, 20162016-10-01
On 9/30/2016 9:53 PM, Winfield Hill wrote:
> P E Schoen wrote...
>>
>> You might also consider an analog Hall effect sensor
>> you can glue to a PCB over a track. Less than a dollar:
>> http://www.mouser.com/ProductDetail/Texas-Instruments/DRV5053EAQLPGM
>
> An elegant idea, Paul. But the 20kHz bandwidth
> is lacking. A current transformer does better
> than that and is also isolated.
I think whether 20 kHz is limiting depends on your application.
Transformers tend to be rather large compared to a TO-92.
--
Rick C
Reply by Neon John●October 1, 20162016-10-01
On 30 Sep 2016 18:53:27 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:
> An elegant idea, Paul. But the 20kHz bandwidth
> is lacking. A current transformer does better
> than that and is also isolated.
I strongly suggest you take the advice of someone else in this thread
and take a look at the Allegro hall effect sensors. Here's the one I
use in my induction heaters.
http://www.digikey.com/product-detail/en/allegro-microsystems-llc/ACS758ECB-200B-PFF-T/620-1323-ND/2042748
I replaced a shunt and an CT. It allowed me to correctly high side
sense for my buck converter power controller. with a 150kHz
bandwidth, it also showed me some stuff that the CT rolled off that
was important to the reliability of the units.
John
John DeArmond
http://www.neon-john.comhttp://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address
Reply by Winfield Hill●September 30, 20162016-09-30
Reply by Winfield Hill●September 29, 20162016-09-29
Jim Thompson wrote...
>
> If you examine the Spice model you'll see the switching.
Given the 5uV typical offset spec, there must be some kind
of chopper / auto-zero activity. And they admit or claim
as much. Often this manifests itself in spectral noise
measurements, but nothing shows for this part up to 100kHz.
Autozero activity is different from flying capacitors, and
wouldn't imply time delays over the 80 - 100kHz bandwidth.
--
Thanks,
- Win
Reply by krw●September 29, 20162016-09-29
On Wed, 28 Sep 2016 22:45:27 +0200, Robert Roland <fake@ddress.no>
wrote:
>On Tue, 27 Sep 2016 09:45:42 -0700, John Larkin
><jjlarkin@highlandtechnology.com> wrote:
>
>>Any thoughts?
>
>An alternative could be the Hall effect sensors from Allegro. They are
>more expensive, but you won't need a shunt resistor, and you get
>galvanic isolation.
They also have GMR detectors that are more sensitive and lower noise.
They're still pretty noisy, though.