Quark ESC Power Board Comparisons/Mods

[GriffinRU]

I'm sorry but I do not think that this is a good idea, based on your questions...

P.S. But if you willing to try, then shoot me PM and I will try to help you out with design.

[sikeston34m]

Originally Posted by GriffinRU

I'm sorry but I do not think that this is a good idea, based on your questions...

P.S. But if you willing to try, then shoot me PM and I will try to help you out with design.

Hi Griffin,

Thanks for volunteering to lend a hand. I appreciate that. I have followed some of your work and respect you as being one of the most knowledgeable people around here on this.

I look at myself in this, like a student, that has alot to learn. But I like to challenge myself, sometimes things work out for the better, and sometimes they don't. But in the process, along the way, knowledge is gained.

I have spent several hours tonight just reading about principles of operation. There's alot to learn, but this is how we grow.

[GriffinRU]

Originally Posted by sikeston34m

Hi Griffin,

Thanks for volunteering to lend a hand. I appreciate that. I have followed some of your work and respect you as being one of the most knowledgeable people around here on this.

I look at myself in this, like a student, that has alot to learn. But I like to challenge myself, sometimes things work out for the better, and sometimes they don't. But in the process, along the way, knowledge is gained.

I have spent several hours tonight just reading about principles of operation. There's alot to learn, but this is how we grow.

Cool, I was planning to start writing in Brian's thread about "ESC's".
Creating threads on modifying ESC's my goal was to help hobbyists to improve their controllers without knowing too deep how it works. And for any good electrical engineer all my tricks are quite obvious, but to design good ESC will require more then just EE...experience helps allot! :)

[sikeston34m]

Ok, according to the data sheets, here's the resistence values:

Big MOSFETS - RDS(ON)= 0.010 ohms max with 0.0082 ohms typical
No Gate Resistence value listed

Quark 80 amp MOSFETS - RDS(ON)= 2.2 megaohms
Gate Resistence = .6 ohms

The Big Mosfet data sheet doesn't list a Gate resistence value.

I wonder how much current the Gate lead circuit in the Quark 80 Brain board can support?

[GriffinRU]

Originally Posted by sikeston34m

Ok, according to the data sheets, here's the resistence values:

Big MOSFETS - RDS(ON)= 0.010 ohms max with 0.0082 ohms typical
No Gate Resistence value listed

Quark 80 amp MOSFETS - RDS(ON)= 2.2 megaohms
Gate Resistence = .6 ohms

The Big Mosfet data sheet doesn't list a Gate resistence value.

I wonder how much current the Gate lead circuit in the Quark 80 Brain board can support?

They should have Rg mentioned somewhere, maybe on the Graph...
This parameter responsible for FET's frequency response, noise and etc when you run simulation and important in design stage.
"Big" fets are usually slow, bulky and rated for high power plus in most cases have lower RDS(On) then "smaller" ones.

You need to check for fet driver part number in Quark 80 brain and study the circuit around it. To calculate required Voltage and Current check for switching frequency and total gate charge. Then do the same calc with different loads and temps.

[sikeston34m]

Here's the Data sheet on the Big Mosfets that I intend to use for the new powerboard.

http://www.fairchildsemi.com/ds/HU%2FHUF75545P3.pdf

Here's the datasheet for the Quark 80 Power Mosfets.

http://www.ortodoxism.ro/datasheets/...3S_Rev1.11.pdf

Griffin, could you take a look at these and tell me if they are capatible with each other?

I'm going to research the driver fet's in the Quark 80 now.
Thanks.

[lutach]

Keep in mind the higher you go in voltage the higher the resistance will be. You can find 40V MOSFETs that have extreme high AMP ratings, but they will be limited to silicon and/or die ratings. Browse www.irf.com or www.infineon.com and you can find a great selection of MOSFETs. There are also various other brands out there.

[GriffinRU]

Originally Posted by sikeston34m

Here's the Data sheet on the Big Mosfets that I intend to use for the new powerboard.

http://www.fairchildsemi.com/ds/HU%2FHUF75545P3.pdf

Here's the datasheet for the Quark 80 Power Mosfets.

http://www.ortodoxism.ro/datasheets/...3S_Rev1.11.pdf

Griffin, could you take a look at these and tell me if they are capatible with each other?

I'm going to research the driver fet's in the Quark 80 now.
Thanks.

Well, it is hard to give you straight answer, because more info requires about application, like in your case what are the current ratings of fet's driver current and power ratings of system providing power to fets' driver IC's? Do they use bootstrap technique in Quark 80 if yes then what capacity bootstrap cap has and what are diode ratings?
Then what exactly you would like to accomplish, stock configuration or higher voltage/current one. How many Fets you would like to use...

As far Rg for "Big" Fet - check on page 6 inside PSPICE model RGATE value 0.87

And, I tend to agree with lutach there are plenty fets, what so special about this one?
I mean both MGM, Quark, Castle... are using probably the best fets for the price and ease of assembly, when you shooting to do something custom you want to get the best (regardless of price and assembly pain) and deal with tuning and tweaking until "green light".

[sikeston34m]

These "Big" Mosfets are ones that I have on hand. Just wanted to do some comparisons and learn more about compatibility.

Correct me if I'm wrong, but Mosfets with a lower on resistence value translates into more voltage at the motor leads with less heat buildup in the ESC.

I took my Quark 80 back out of the case to investigate the driver fets and their ratings. They are sandwiched between the power board and the brain board. I can't get a good look at them. I'm hoping to catch Zeropointbug and ask him for a closeup view of the brain board that he has already disassembled.

"I mean both MGM, Quark, Castle... are using probably the best fets for the price and ease of assembly, when you shooting to do something custom you want to get the best (regardless of price and assembly pain) and deal with tuning and tweaking until "green light"."

In Business, I'm sure they are balancing the most profitable (cheapest) way to go and live up to the ratings of their ESC's.

On the Custom work, I can't aggree with you more. I'm not worried about the cheapest route.

Is it possible to use a Quark brain board from an ESC that's rated for 2 to 6 Lipo cells and adapt it to a larger capacity power board for a 10 or 12 lipo cell rating?