Forums

0.2MHz - 2MHz step up transformer

Started by Paul Jackson January 22, 2012
Paul Jackson wrote:
> On Sun, 22 Jan 2012 10:27:38 -0500, Jamie > <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote: > > >> Being a function generator as the source, I think you better start >> thinking of HV amplifiers instead. A DC coupled one to be exact. >> > > What would be your opinion of these? > > http://www.piezomaster.com/ >
Quote "low enough in cost". http://www.piezomaster.com/pricing.htm That buys about ten excellent lunches for two with two large Hefeweizens on tap at our Japanese restaurant. I prefer those lunches :-) Then quote "We now offer high frequency drivers up to 100 kHz". That ain't gonna cut the mustard. -- Regards, Joerg http://www.analogconsultants.com/
"Paul Jackson" <pauljackson@thermalux.com>

> > I am looking for an impedance matching transformer that will convert > the 50 Ohm output of my function generator and to a 1K Ohm resistive > load. > > That provides a 20x step-up as well, so with losses 10V yields maybe > 100V. > > Frequency range is anywhere between 200KHz to 2MHz. Required current, > up to 20mA. > > I would definitely prefer a ready-made transformer. Does anyone know > under what application heading one might be found? >
** Look under "sky hook suppliers" and "tooth fairies". .... Phil
On Jan 22, 6:57=A0pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Sun, 22 Jan 2012 04:55:02 -0800 (PST),BillSloman > > > > > > > > > > <bill.slo...@ieee.org> wrote: > >On Jan 22, 1:05=A0pm, pauljack...@thermalux.com (Paul Jackson) wrote: > >> I am looking for an impedance matching transformer that will convert > >> the 50 Ohm output of my function generator and to a 1K Ohm resistive > >> load. > > >> That provides a 20x step-up as well, so with losses 10V yields maybe > >> 100V. > > >> Frequency range is anywhere between 200KHz to 2MHz. Required current, > >> up to 20mA. > > >> I would definitely prefer a ready-made transformer. Does anyone know > >> under what application heading one might be found? > > >The only kind of transformer that has a hope of offering that kind of > >bandwidth is a transmission line transformer. > > At 2 GHz, yes. But 2 MHz isn't especially fast.
It's a 10:1 bandwidth range. Ferrites that are good for 2MHz don't have particularly high permeabilities, and lots of turns to make up for the low permeability of the core tend to leave you with inconveniently low self-resonance frequencies. Do you want to design a suitable more-or-less conventional transformer? I tried it once, and a transmission line transformer made with twisted pair is what worked. -- Bill Sloman, Nijmegen
On Sun, 22 Jan 2012 17:04:58 -0800, Joerg <invalid@invalid.invalid>
wrote:

>That buys about ten excellent lunches for two with two large Hefeweizens >on tap at our Japanese restaurant. I prefer those lunches :-) >
Great. If I was there you could invite me to lunch and draw a design on a Japanese napkin ... preferably before the beers. I can't really afford a Tek HV amp, and I only need a few hundred volts. So I will keep creeping up the food chain, one start-up company at a time. Paul
"Bill Sloman" <bill.sloman@ieee.org> wrote in message 
news:b109bfa8-5226-482a-a26d-f63d01d15ae3@f1g2000yqi.googlegroups.com...
> > At 2 GHz, yes. But 2 MHz isn't especially fast. > > It's a 10:1 bandwidth range. Ferrites that are good for 2MHz don't > have particularly high permeabilities, and lots of turns to make up > for the low permeability of the core tend to leave you with > inconveniently low self-resonance frequencies.
If you were designing a power transformer, this might be the case. Typically NiZn ferrites are used, with Bmax ~ 0.3T and mu_r ~ 800, like Fair-Rite #43. These might be usable close to Bsat for small transformers, but the core loss requires Bmax < 0.1T for most power applications. Which is fine, since it doesn't take much core at 2MHz to achieve that. But signal applications under 1W are hardly the concern of core loss. Typically, a pulse transformer is wound on the highest permeability core possible (e.g., Ferroxcube 3E5, Magnetics 'W'), which accordingly has very high losses at high frequency (complex permeability is essentially imaginary), but still has greater total permeability up to several MHz than the HF material. This means you can use simpler coil geometry, giving a higher SRF despite the higher inductance. As a bonus, the SRF is dampened by the core losses at those frequencies.
> Do you want to design a suitable more-or-less conventional > transformer? I tried it once, and a transmission line transformer made > with twisted pair is what worked.
Honestly, I can make a transformer with that kind of bandwidth by sitting on a ball of wire! Typically I see >10MHz from the gate drive transformers I carelessly put together, and ~50MHz with interleaving. If more than that is required, twisted pair gets involved. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
On Jan 23, 1:05=A0am, pauljack...@thermalux.com (Paul Jackson) wrote:
> I am looking for an impedance matching transformer that will convert > the 50 Ohm output of my function generator and to a 1K Ohm resistive > load. > > That provides a 20x step-up as well, so with losses 10V yields maybe > 100V. > > Frequency range is anywhere between 200KHz to 2MHz. Required current, > up to 20mA. > > I would definitely prefer a ready-made transformer. Does anyone know > under what application heading one might be found? > > Paul Jackson
an emitter follower perhaps? transformers are so last Tuesday...
HardySpicer wrote:
> > On Jan 23, 1:05 am, pauljack...@thermalux.com (Paul Jackson) wrote: > > I am looking for an impedance matching transformer that will convert > > the 50 Ohm output of my function generator and to a 1K Ohm resistive > > load. > > > > That provides a 20x step-up as well, so with losses 10V yields maybe > > 100V. > > > > Frequency range is anywhere between 200KHz to 2MHz. Required current, > > up to 20mA. > > > > I would definitely prefer a ready-made transformer. Does anyone know > > under what application heading one might be found? > > > > Paul Jackson > > an emitter follower perhaps? transformers are so last Tuesday...
Your computer runs off AA alkalines, I gather. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
On Jan 23, 4:40=A0am, "Tim Williams" <tmoran...@charter.net> wrote:
> "BillSloman" <bill.slo...@ieee.org> wrote in message > > news:b109bfa8-5226-482a-a26d-f63d01d15ae3@f1g2000yqi.googlegroups.com... > > > > At 2 GHz, yes. But 2 MHz isn't especially fast. > > > It's a 10:1 bandwidth range. Ferrites that are good for 2MHz don't > > have particularly high permeabilities, and lots of turns to make up > > for the low permeability of the core tend to leave you with > > inconveniently low self-resonance frequencies. > > If you were designing a power transformer, this might be the case. > Typically NiZn ferrites are used, with Bmax ~ 0.3T and mu_r ~ 800, like > Fair-Rite #43. =A0These might be usable close to Bsat for small > transformers, but the core loss requires Bmax < 0.1T for most power > applications. =A0Which is fine, since it doesn't take much core at 2MHz t=
o
> achieve that. > > But signal applications under 1W are hardly the concern of core loss.
10V into 50R is 2W.
> Typically, a pulse transformer is wound on the highest permeability core > possible (e.g., Ferroxcube 3E5, Magnetics 'W'), which accordingly has ver=
y
> high losses at high frequency (complex permeability is essentially > imaginary), but still has greater total permeability up to several MHz > than the HF material. =A0This means you can use simpler coil geometry, > giving a higher SRF despite the higher inductance. =A0As a bonus, the SRF=
is
> dampened by the core losses at those frequencies.
Typically pulse transformers are transmission line transformers wound with a twisted pair transmission line, as I pointed out in my original response - not a lot of the high frequency flux makes it into the core.
> > Do you want to design a suitable more-or-less conventional > > transformer? I tried it once, and a transmission line transformer made > > with twisted pair is what worked. > > Honestly, I can make a transformer with that kind of bandwidth by sitting > on a ball of wire! =A0Typically I see >10MHz from the gate drive > transformers I carelessly put together, and ~50MHz with interleaving.
How good are they at 200kHz?
>=A0If more than that is required, twisted pair gets involved.
You seem to live in a different universe from mine. -- Bill Sloman, Nijmegen
On a sunny day (Sun, 22 Jan 2012 16:58:20 -0800) it happened Joerg
<invalid@invalid.invalid> wrote in <9o3pleF6n6U1@mid.individual.net>:

>Believe it or not but I never owned an EPROM programmer.
Oh, I believe it, you chiseled the bits in no?
On a sunny day (Mon, 23 Jan 2012 01:57:39 -0500) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<4F1D04E3.A0684B56@electrooptical.net>:

>HardySpicer wrote: >> > I am looking for an impedance matching transformer that will convert >> > the 50 Ohm output of my function generator and to a 1K Ohm resistive >> > load. >> > >> > That provides a 20x step-up as well, so with losses 10V yields maybe >> > 100V. >> > >> > Frequency range is anywhere between 200KHz to 2MHz. Required current, >> > up to 20mA. >> > >> > I would definitely prefer a ready-made transformer. Does anyone know >> > under what application heading one might be found? >> > >> > Paul Jackson >> >> an emitter follower perhaps? transformers are so last Tuesday... > >Your computer runs off AA alkalines, I gather. ;) > >Cheers > >Phil Hobbs
The OP mentions'transformer'. But this sounds like a simple video output CRT driver: +120V +5 | | R 1000 C2 R |----------||----------- 100Vp Z=1k C1 | c ----||----------- b | e NPN BF??? (video output driver) | | R 10k R 100 | | for a gain of about 10 /// /// You could use a dozen 9V batteries :-)