[TriEmbed] High Current Sensing

[Adam Haile]

Side question... and suggestions for test loads for that much current?


On Sat, Jun 14, 2014 at 12:02 PM, Adam Haile <email at adamhaile.net> wrote:

> Very nice :) Will check those out. I assume those that the board traces
> for the power pass-through would still have to be massive though?
>
> According to the calculator in KiCad, 2.75 mil trace (OSH Park standard)
> for 100A and a 20C temp rise would have to be 56mm wide!
> And am I reading it right that these don't need a heat sink? I'm assuming
> because it's not a typical ultra low resistance shunt and has effectively
> no resistance, therefore little to no wattage absorbed?
>
>
> On Sat, Jun 14, 2014 at 11:50 AM, Fred Ebeling <FEbeling at ecpdesigns.com>
> wrote:
>
>>   Hi
>>
>> I would recommend one of the allegromicro products.  They have evaluation
>> boards and I actually
>> use one to monitor my power supplies under development.  Its big
>> advantage is its isolated and
>> you only have to pass the power thru the device.  No voltage drop, no
>> power loss.
>>
>>
>> http://www.allegromicro.com/en/Products/Current-Sensor-ICs/Fifty-To-Two-Hundred-Amp-Integrated-Conductor-Sensor-ICs.aspx
>>
>>
>> Fred Ebeling
>> ECP Designs
>>
>>
>>
>>  *From:* Adam Haile <email at adamhaile.net>
>> *Sent:* Saturday, June 14, 2014 11:35 AM
>> *To:* triembed at triembed.org
>> *Subject:* [TriEmbed] High Current Sensing
>>
>>  As those that saw my projects at the Maker Faire know, I work with a
>> lot of high current LED projects. So I'm always looking for higher current
>> supplies and my variable bench supply definitely doesn't cut it so I
>> generally use supplies like the 5V/40A supply I used for my 24x24 matrix.
>> But that is even a too little for some of the projects I have planned. I'm
>> thinking about getting a 500 - 700W (@5V) supply (something like this:
>> http://www.ebay.com/itm/370888481354) and building it out with a few
>> more features.
>>
>> Mainly, I want to add built in current sensing that would be displayed on
>> an LCD screen (likely all Arduino controlled). The supply itself would be
>> unmodified - I'm not crazy. I would just add all that between the supply
>> output and connectors on the outside of an enclosure I would build.
>>
>> So, my main question is if anyone has any advice for how I could go about
>> sensing this much current? I'm thinking about using something like the TI
>> INA219 (http://www.ti.com/product/ina219) which, with the right shunt,
>> should be able to handle it and would have a nice I2C interface. I'd also
>> like to have 2 - 4 separate outputs, each with their own separate sensor...
>> so each would need to handle up to 100A or so.
>>
>> I realize that running the current through any PCB trace to the shunt
>> would probably require insanely wide traces, so is there a good, high
>> precision shunt that would work off PCB?
>>
>> Basically, I don't know what I don't know, so I'd love any direction that
>> could be given.
>>
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>>
>
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