Otto`s replication of Steven Mark`s TPU

[tishatang]

Kent
thanks

chrisC
I did not know Otto was expecting a new scope.  I have had other things on my mind the last two months.  Life is interesting.  My name is also Chris and I have already made plans to visit a friend in Santa Cruz in about two weeks.  I will be there for 2 to 4 days.  So, we don't have to worry about the scope getting damaged in shipping!  If its OK with Otto, it's OK with me to have it.

I also have three spools of wire about 8 to 10 lbs each.  As I recall one is 30 awg, one is 5 strand litz 26 awg, and one is 12 awg inulated like house wiring only stranded I think?  Make a reasonable offer plus what you said for shipping and I can add that to my travel expenses to China.  Airfare alone is $1200!

Email me your contact info.  I think it is still active?

Tishatang (aka ChrisG)

[chrisC]

@Tishatang (chrisG!)

Thanks indeed! First things first, let's let Otto confirm that he is not in need of another scope. I would rather do that first. It's only the right thing to do.

If he does not need it, I will contact you privately via the forum. I'm 45 minutes drive to the Santa Cruz mountain and if your scope is not too expensive and it's available, I'll be happy to drive down to Santa Cruz to meet with you or you're welcomed to visit my home in San Jose!

Will keep in touch! (p/s: my dad's from China)

ChrisC

[Motorcoach1]

no complex circuits needed just listen and learn

[MeggerMan]

Hi Grumpy,
Yes I have read the document on gate drives for mosfets but it does not help.
This is what a mosfet driver IC is - a set of transistors setup in a push-pull arrangement.
I think if you are not careful then you will end up consuming more power turning the mosfet on and off than the actual mosfet uses itself to drive the controller coil.
Perhaps you can do some tests to see what switching times you get with and without the speed up circuit.

The DEIC420 I found has 16 bypass capacitors of various values to get the required 20A into the device in 2-6ns - this is heavy stuff.

Anyway, I think Roberto may have a much cheaper and simpler solution.
I suspect the DEIC420 may be overkill.
I will keep looking to see if I can come up with something better.

[edit]
OK here we go, brand new (2006) from Texas Instrument: UCC7200
http://focus.ti.com/lit/ds/symlink/ucc27200.pdf
3A rise/fall time 8ns/7ns (typical with 12v)
Cost $3.10 from Mouser or $2.79 from Digikey
This is more like it, just need to find a UK/European supplier now.

Few more:

TPS2829
http://focus.ti.com/docs/prod/folders/print/tps2829.html
2A rise/fall 14ns(typical) 30ns(max) cost 0.61GBP

LM5110
http://www.farnell.com/datasheets/55858.pdf
5A rise/fall 14ns/12ns (typical) cost 0.81GBP

TPS2812
http://focus.ti.com/lit/ds/symlink/tps2812.pdf
5A rise/fall 14ns/12ns (typical) cost 0.88GBP

MC34152P (dual)
http://www.farnell.com/datasheets/36798.pdf
1.5A rise/fall 14ns/15ns (typical) cost 1.2GBP

IR4426PBF
http://www.irf.com/product-info/datasheets/data/ir4426.pdf
1.5A rise/fall 15ns/10ns (typical) cost 1.2GBP

LTC3901EGN
http://www.farnell.com/datasheets/84113.pdf
2A rise/fall 15ns/15ns (typical) cost 3.5GBP

Its difficult to compare specs as each manufacturer uses a different supply voltage for their typical rise/fall time tests, but most seem to use 12v.
So in summary the UCC7200 is the best value for money and its speed is completely unrivaled.

Regards
Rob

[tishatang]

Motorcoach1

Somehow I missed your post.
Thanks a lot.  I wished I could have contributed more.
Just hitching on to you guys shirt tails has been very gratifying to me

Tishatang