[TriEmbed] RaspPi Power Protection

[Rodney Radford]

I couldn't find the MAX486C used in that schematic, but I did find other
chips in the MAX486 family made by Maxim.  The first few paragraphs explain
how the chip works, and what the P and N channel MOSFETs do (one is for
overvoltage to turn off the supply to the load, and other is for negative
voltages to turn off the incoming supply completely).

A nice find and will work great for your need.

On Fri, Jan 15, 2016 at 1:42 PM, Adam Haile via TriEmbed <
triembed at triembed.org> wrote:

> Ahh, yeah. That little protection circuit (bottom left corner I assume)
> quickly gets WAY over my head. I see what chips are there but have no idea
> what that actually *does.* This is why I left CompE for SoftE... analog
> circuits fry my brain :P Will have to research those chips some more and
> see if my brain doesn't melt :P Thanks for the link... at least now I see
> how it could/should be done. And in a VERY similar application.
>
> On Fri, Jan 15, 2016 at 1:31 PM, Alex Davis via TriEmbed <
> triembed at triembed.org> wrote:
>
>> Check out how they did it on the Adafruit Pi Matrix Hat:
>>
>> https://learn.adafruit.com/system/assets/assets/000/022/441/original/leds_schem.png?1421437847
>>
>> It's all 5v, but the power input protection would be of interest.
>>
>> In my application, I run a 62x32 matrix off the same power supply as the
>> Pi2, and to keep things happy required significant bypass caps across
>> the power input to the matrix.
>>
>> > I'm playing with an idea for a Pi Zero "Hat" that would involve LEDs...
>> I
>> > know, shocking.
>> >
>> > So, I figured it would be possible to power the Pi off the LED power
>> > input
>> > but I want to support 12V LEDs as well. My current plan is just a jumper
>> > (solderable probably) and a stern warning that it's your own fault if
>> you
>> > fry your Pi.
>>
>>
>>
>> --
>> "The theater of noise is proof of our potential."
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>>
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>>
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