How to use the MOSFET Power Board

[2k1Toaster]

Pins 1 and 2 are connected together, and need to be supplied with the same voltage as what you are switching. Pin #4 controls the MOSFET on the left when grounded, and pin #3 controls the MOSFET on the right when grounded.

The Fusion Brain works with switched grounds. So when you connect the FB to the MOSFET board, connect the + side to the "bottom" pin and the - side to the "top" pin. The drains of the MOSFET are on the outside bottom 4 pins, and the sources are the middle two.

For best operation, the sources should be tied to ground, (it needs to be the same ground as the Fusion Brain). Then your load gets power normally, and the ground of your load is connected to the drain pin on the MOSFET. So when the Fusion Brain turns on an output, the pin is grounded, and the MOSFET allows current to flow through the power source, to the load, to the MOSFET, and to ground completing the circuit and turning on the load.

[ACCLR8N]

Thanks for the info. I'm gathering bits for my HVAC and now I'm changing my mind again on blower control. If I understand this correctly, this board can PWM two motors independently? Can I steal a picture from your website and post here with mark-ups for the electron challenged?

[2k1Toaster]

Yup, you can switch two loads fast and continuously like PWM with these boards.

If you want to mark up a picture, go for it

[UniqelyCommon]

This is my best guess off the information here, hopefully 2k1Toaster will review it and give official approval or blacklist

Designed for use in a larger collection (but def. needs aesthetic improvements! I'm open to suggestions/edits )

EDIT: Oh, just remembered there's no technical data included!! Doh! Good to inform the user as to max voltage, amperage, etc. I'll be adding that in soon (but if there are/not errors it'd be nice to know, I *really* don't want to lead someone astray and break their hardware trying to be helpful...)

EDIT 2: Started to add technical data, changed AC information, added (amateur) background

EDIT 3: Removed background (just too much, both visually and for smooth scrolling), still need technical data (2k1? )

[UniqelyCommon]

Doing some research, do NOT use the MOSFET board for AC loads!!! Ignore that diagram!

[GadgetBandit]

As a graphic designer and not a EE, diagrams and sample files are really really appreciated (hint-2k1).

Thanks for posting this.

GadgetBandit

[OldSpark]

Doing some research, do NOT use the MOSFET board for AC loads!!! Ignore that diagram!

OUCH!

Could be solved with larger Vds (only 100V), but I would argue to stay away from domestic/mains/wall AC etc - that get's way too litigious! (And you'll need Vds > 400V anyhow....)
(Though I presume you have the right creep distances - eg for >400V etc???)

It's better to have the FB or FETs control a mains/AC rated relay "wired in accordance with YOUR local laws & regulations...." with every required protective caveat you did & didn't think of....

Better still....
"WARNING: Not for AC use!" (Except LVAC where permitted...)

[GadgetBandit]

"wired in accordance with YOUR local laws & regulations...."

My granddad used to say "Just keep a fire extinguisher handy."

GadgetBandit

[UniqelyCommon]

As a graphic designer and not a EE, diagrams and sample files are really really appreciated....
Thanks for posting this.

No problem, just compiling what little I know hopefully its correct
(For what its worth, as an EE/ME student and not a graphic designer, its hard for me to make pretty diagrams or backgrounds )

My granddad used to say "Just keep a fire extinguisher handy."

Love it, going to use it!

Could be solved with larger Vds (only 100V), but I would argue to stay away from domestic/mains/wall AC etc - that get's way too litigious! (And you'll need Vds > 400V anyhow....)

Yeah, but a pity as that's what I'm going for Now I'm looking at TRIACs and all sort of EE hoodwinkery that's (at best) a few semesters ahead of me

This thread seems to be the most promising of those I've found for dimming a 120VAC supply. Not designed for PWM though, sadly...

[OldSpark]

"wired in accordance with YOUR local laws & regulations...."
My granddad used to say "Just keep a fire extinguisher handy."

A fire extinguisher is usesless.
A spade is better - it both digs the hole to dump the torso, and can disperse any flame retardant.

This thread seems to be the most promising of those I've found for dimming a 120VAC supply. Not designed for PWM though, sadly...

The same opto-TRIAC (or two SCRs) circuit is used for phase control which is PWM (where "on" occurs after a phase delay and stays on until next zero crossing).
Or for less interference & depending on the load, it could remove full half-cylces - eg, for 1/120th dim; off for a full half cycle, on for the rest; or for 1/2 dim: on every 2nd full cycle etc (to balance +ve & -ve to avoid dc offsets).

Not that either of the above use uPC or PIC PWM functionality per se - it is usually easier calculating the required phase or cycles and turning the optocoupler on as appropriate.


Or use a suitably rated MOSFET or IGBT, but isolate with an optocoupler etc for safety's sake.