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Another Flyback Driver circuit... Why use 24 volt power supply? I want to use 169.70 VDC

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LAN_403

TwirlyWhirly555

Sat Jun 07 2014, 02:16PM

Registered Member #4104 Joined: Fri Sept 23 2011, 06:54PM
Location: Uk .
Posts: 122

I Say go half bridge too its a lot less of a pain to get going and gives just as good results and better

With 60V 50A cheap mosfets and a PLL driver ( Can be fixed Frequency driver ) from a 50V DC bridge supply I was getting This

With the correct FETs or IGBTs and driver it can run at 120V no problems and its a lot less failure prone .

tarakan2

Sat Jun 07 2014, 06:08PM

Registered Member #3859 Joined: Sun May 01 2011, 03:47PM
Location:
Posts: 179

Mads Barnkob wrote ...

Sigurthr wrote ...

Why are you trying to use a Royer oscillator when you could much more easily use a standard half bridge to drive the flyback transformer at whatever input voltage you like. A standard SSTC style driver and half bridge inverter circuit being fed by a variable frequency oscillator will let you adjust output power by moving closer to or away from the resonance point of the flyback, giving you precise control of the output without needing a variac.

It could be as simple as a 555 feeding a UCC37321/UCC37322 pair into a GDT, which drives a half bridge of FDL100N50F MOSFETs. You'd be good up to ~480V DC Bus and capable of switching more amps than your wall can deliver provided you cool the fets well.

Sigurthr is right, there is no reason to try and brute force a Royer oscillator to do things it can not handle with the kind of switches available, the self oscillating nature of this circuit works fine within some limited boundaries and outside of them it burns or needs auxiliary circuits where it gets even more complex than just building a half bridge driver with something like the TL494 IC.

I made a TL494 driver that easily kills the flybacks from over voltage before the bridge explodes:

I like this circuit.

I am lazy to do math, so I would like to ask if you know what
AL value (nano-Henries-per-turn-squared or nH/N2) your ferrite core had.

MAX4420 is a buffer amplifier and a comparator that brings the logic 1 to the supply voltage and switches off when logic voltage is near 0V.
As I understand, I can drive this circuit with various sources of AC signal that is above 2.4V

ucc37321 is another IC that you have used in the Tesla coil driver that can be used with 1 volt logic input according to the datasheet. Am I correct?

So I can drive my Flyback with an AD9851 (outputs 1.5V), an Arduino microcontroller and a dial in frequency input.

I like that antenna in the circuit. I made a discovery that Ne-2 neon bulb can be used to trigger low voltage events with high voltage since if gas is ionized by an intense electric field, Ne-2 starts to conduct current through the leads. High voltage is isolated by the glass and is delivered to the bulb by a single wire conductor. This is also how I measure HV alternating currents with an oscilloscope and it works up to 100kHz...

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I have two 1950s flyback transformers. They have no rectifiers inside and I want to use them. I am afraid of burning them because I had to acquire two 1950s TVs to pull them out of.

Thank you.

Mads Barnkob

Sun Jun 08 2014, 07:01AM

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

tarakan2 wrote ...

Mads Barnkob wrote ...

I am lazy to do math, so I would like to ask if you know what
AL value (nano-Henries-per-turn-squared or nH/N2) your ferrite core had.

MAX4420 is a buffer amplifier and a comparator that brings the logic 1 to the supply voltage and switches off when logic voltage is near 0V.
As I understand, I can drive this circuit with various sources of AC signal that is above 2.4V

ucc37321 is another IC that you have used in the Tesla coil driver that can be used with 1 volt logic input according to the datasheet. Am I correct?

So I can drive my Flyback with an AD9851 (outputs 1.5V), an Arduino microcontroller and a dial in frequency input.

I have two 1950s flyback transformers. They have no rectifiers inside and I want to use them. I am afraid of burning them because I had to acquire two 1950s TVs to pull them out of.

Thank you.

I used AL:5750nH cores, maybe it was N30 material.

You can use any MOSFET driver that is capable of driving your MOSFETs, the MAX4420 was no specific choice, but what I had at hand.

The old disc flyback transformers are lovely, since they do not have the built-in rectifier you can use them for experiments that require high voltage AC, f.ex. a plasma globe.

Sulaiman

Sun Jun 08 2014, 11:15AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Forgot to ask the obvious question;

What do you want to do with the eht output?

For just making arcs the 1/2-brdge is probably the best,

if you want very high voltage d.c. at low current for 'serious' experimental work,
I suggest simple flyback topology as it puts the least voltage stress on the o/p diode(s)

tarakan2

Mon Jun 09 2014, 06:14AM

Registered Member #3859 Joined: Sun May 01 2011, 03:47PM
Location:
Posts: 179

I want to build a high voltage AC supply for Tesla Hairpin circuit, and other sperk-controlled experiments.

I want to stick with

http://kaizerpowerelectronics.dk/high-voltage/tl494-flyback-driver/

I want to know what kind of ferrite was used on the GDT. What are the nanoHenries per turn?
Thanks.

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