Scope shots of clean kicks

[Jdo300]

Hi Bob.R,

I definitely agree with your thoughts on adding the kicks. Once I perfected my harmonic pulse circuit and fed the output through a small transformer, I saw some VERY interesting kicks on the secondary which had the same exact harmonic pulses that you showed. Though I was only pulsing at around 15 kHz at the time. Here's a scope dump from the setup:



I noticed that you only get this effect with a clean square wave with a VERY fast rising edge. These other harmonic pulses are definitely a little extra input from the environment that we can pulse on top of to gain more on the output. Like you said, that explains the purpose of using two frequencies that are harmonics of each other.... And the closer you get to the pulse harmonics lining up, the more energy! P = V^2 / R. so if we combine two waves to get double the voltage, we actually get 4 times the power at that point in time.

Also, as for getting nice clean pulses, I also want to add that you should use shielded coax to run from the control board to the MOSFET gates (if the MOSFETs are separated from the rest of the board. Another thing is NOT to use the solder less breadboards because they have a lot of capacitance and can make the harmonic signals all goto garbage once you get up into the higher frequencies. From my experience, you really only need to worry about the signals coming out of the MOSFET drivers, so make sure the wires for that are well shielded/isolated from each other and use the proper caps specked out in the data sheet. For that, I am able to get very clean square waves out of it all the way up to about 800 kHz before I start to see ringing in the line.

God Bless,
Jason O

[CTG Labs]

Hi Jason,

Can you confirm you can see these pulses without the transformer?  I mean so we can discount these as Soliton pulses due to sloshing of the bloch walls in the core material?


Thanks,

Dave.

[bob.rennips]

Hi Jason,

Great looking kick!

Good advice on using coax. I got my best square waves with the mosfets within 1-2cm of the driver chips. The driver chip to mosfet connection is definately key.

Do you know why the train of follow up pulses are close together but start a fair distance from the main pulse ?

The transformer - is this a self wound air core bifilar or are you looking at say a small audio transformer ?

Cheers ,Bob

[eldarion]

Well, here is a pic of my TPU v4.  I have yet to receive (and therefore install) my MOSFET drivers, but when I do, I just have to plug them into two IC sockets and fire it up!

The board on the back is a delta-sigma ADC, and the MOSFETs on the driver board are IRF640s.

[Jdo300]

Hi Dave & Bob,

I was using a small transformer when I did that test. At the time I was simply testing my new control circuit to make sure it was functioning correctly. I plan to do some more testing on this to see if I can get the same pulses on an air-cored coil.

God Bless,
Jason O