www.robowars.org

RoboWars Australia Forum Index -> Technical Chat

Silicon Carbide mosFET's - Potential new Controller Tech


Post new topic   Reply to topic
  Author    Thread
Spockie-Tech
Site Admin


Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


 Reply with quote  
Silicon Carbide mosFET's - Potential new Controller Tech

Hmm.. After commenting on that new integrated controller Aaron posted, I just had a quick check to see what current SOA (State Of the Art) mosFet tech was and found this.

http://www.digikey.com/us/en/ph/Cree/cmf20120d-mosfet.html

Very Interesting.

Rds is *much* higher (*80*mOhm rather than 5mOhm) than the well known 1405 Fet (for Comparison) which means higher internal power losses and increased temperature load for a given operating power level, but the Thermal Cooling Resistance (R(theta)JA) is about 1/3 lower at 40deg/W rather than the 62deg/W of the 1405, meaning it can dump heat into its cooling system a fair bit faster to help.

About 1/2 the gate-charge (nanoCoulombs) requirements means its easier to switch states quickly than the 1405, making the fet drivers have to work less to flip the bridge.. although the much higher Rds would mean you would need a lot of them in parallel to get equivalent low voltage performance.

The lower Operating Junction temperature of 135c vs the 1405's 175c is a bit confusing, from what I read, SiC Fets were supposedly going to be able to survive at ridiculously high operating temperatures without destruction.. Maybe its a limitation of the package rather than the substrate ?

But, the *killer* spec is Vdss.. *1200* volt breakdown vs the 1405's *55* volt !!

OK, Maybe not much excitement for the <36 volt Combat Robot Control world, since the High Rds sucks a bit for Low Volt, High Current applications, but I bet the ESC designers for the E.V. world with their 300+ volt battery packs are drooling about now.

Although at $30+ each, that will probably dampen any major excitement until volumes start to rise and price comes down.. but its good to see a start in this area,

Now hurry up and get me the 600 degree C operating and <10mOhm Rds devices for <$5 I heard about !! Wink

(Actually I also read some stuff that the manufacturers were quite likely to only slowly and gradually bring in this new tech, because they knew it would destroy sales of existing products if not progressively introduced.. *dirtbags*, holding back on new tech to extract maximum $$ from a market. who do they think they are.. Intel ? Wink )
_________________
Great minds discuss ideas. Average minds discuss events. Small minds discuss people

Post Sun Feb 10, 2013 11:13 am 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
marto
Experienced Roboteer


Joined: 08 Jul 2004
Posts: 5459
Location: Brisbane, QLD


 Reply with quote  

Yeh it will trickle through but might be a while. Although 1200V wow. Not sure what I coudl do with it but I am sure it will have an impact.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Post Sun Feb 10, 2013 12:09 pm 
 View user's profile Send private message Send e-mail MSN Messenger
Valen
Experienced Roboteer


Joined: 07 Jul 2004
Posts: 4436
Location: Sydney


 Reply with quote  

1200V means operations on 600V with margin.
That's the sort of voltage traction packs are going to run soon.

It'd also be good for high voltage DC transmission lines I'd imagine.
_________________
Mechanical engineers build weapons, civil engineers build targets

Post Mon Feb 11, 2013 9:15 am 
 View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger MSN Messenger ICQ Number
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 1 of 1


Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

 

Last Thread | Next Thread  >
Powered by phpBB: © 2001 phpBB Group
millenniumFalcon Template By Vereor.