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zzz_julian_zzz

Sun May 27 2012, 02:50PM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Hi,

I would like to know if this IGBT (MG100Q2YS51) requires special driving technique unlike on the simple UCC IC drive only?
can it be driven only by a N/P discreet fets? its for my DRSSTC (approx 100Khz Fres)..

Thanks in advance

Mads Barnkob

Sun May 27 2012, 03:50PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

I suggest that you look up the output characteristics of the UCC that you are going to use, look up the gate characteristics of the IGBT and with the help of this article

you can find the answer and learn something :)

zzz_julian_zzz

Mon May 28 2012, 04:47AM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Thanks for the reply, now I knew that I must have a special driving circuit to make this IGBT work properly, however, where can I borrow some design which consist of this techniques, I've seen

but I don't know where does this SMPS winding and Isolated signal came from??? =/ do you have any complete schematics ? THanks

Dr. ISOTOP

Mon May 28 2012, 08:38AM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

zzz_julian_zzz wrote ...

Thanks for the reply, now I knew that I must have a special driving circuit to make this IGBT work properly, however, where can I borrow some design which consist of this techniques, I've seen

but I don't know where does this SMPS winding and Isolated signal came from??? =/ do you have any complete schematics ? THanks

Steve's gate drive (and most high-performance gate drives) requires a floating power supply (transformer with a couple KV isolation between the two windings) and a "floating" logic signal (optocoupled or magnetically coupled) to operate. Basically, the ground of the gate driver has to be isolated from the ground of the controller.

zzz_julian_zzz

Mon May 28 2012, 10:02AM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

You said a KV isolation, but why do we need to use a step up transformer (w/smps) into KV to supply the gate drive circuit?
I really don't get it. I know that it should be isolated,

but why not use another typical 220vAC to 25vAC transformer? like in the low voltage controller power supply. And NOT using SMPS ... any particular reason for this? THanks again.

Dr. ISOTOP

Mon May 28 2012, 09:06PM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

zzz_julian_zzz wrote ...

You said a KV isolation, but why do we need to use a step up transformer (w/smps) into KV to supply the gate drive circuit?
I really don't get it. I know that it should be isolated,

but why not use another typical 220vAC to 25vAC transformer? like in the low voltage controller power supply. And NOT using SMPS ... any particular reason for this? THanks again.

Whoever said anything about step-up? The supply should provide voltage equal to your gate drive voltage.
Steve Ward, and most professional gate drivers, use a switching power supply, but that doesn't mean you have to...

Neet Studio

Mon May 28 2012, 10:35PM

Registered Member #4037 Joined: Fri Jul 29 2011, 03:13PM
Location:
Posts: 86

>You said a KV isolation but why do we need to use a step up transformer (w/smps) into KV to supply the gate drive circuit?

Isolation means the circuit can handle up to a different of 1KV between the input and output. It does not mean the circuit needs 1kV to operate.

Also see wiki:

zzz_julian_zzz

Tue May 29 2012, 10:57AM

Registered Member #3964 Joined: Thu Jun 23 2011, 03:23AM
Location: Valenzuela City
Posts: 332

Thanks for the replies, So the supply doesn't need an SMPS, as long as it is isolated from control circuit and other driving circuit. my only question is, is it possible to couple the isolated driver input(logic output of the controller) from s.wards design on a ferrite core only and not on a opto-coupler IC?

EDIT: OR isolation of secondary of the gate drive circuit transformer supply from its secondary winding of atleast 1kv? Why do we need to isolate the power input? so that it will not interfere with the supply of the logics? Thanks again from your replies (i'm a little lost here)

Ash Small

Tue May 29 2012, 12:24PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

zzz_julian_zzz wrote ...

.

EDIT: OR isolation of secondary of the gate drive circuit transformer supply from its secondary winding of atleast 1kv? Why do we need to isolate the power input? so that it will not interfere with the supply of the logics? Thanks again from your replies (i'm a little lost here)

I think the answer to your question is that the secondaries that drive the high side IGBT's are floating at the supply rail voltage.

Steve Conner

Tue May 29 2012, 12:29PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Yes, and what's worse, they have the high frequency output superimposed on them too. A pretty severe requirement for an isolation barrier.

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