High Voltage Flyback Driver with PWM

[@noelandrew3600]

Did this same thing about a year or so back but used a mosfet modual as well with the same square wave gen. really good for working out the best frequecy for each fly back and pushing it to the best output. and i can drive it with 24v.

[@Enigma758]

What about using a pull down resistor on the mosfet gate to help turn it off more quickly (due to gate capacitance)?

[@ludicscience]

That's good advice!

[@imagine_laabs]

What do you mean and what resistance value do I need?

[@Enigma758]

@@imagine_laabs mosfets are voltage controlled devices operate using capacitance. Without a gate pull down resistor, the mosfet "wants to" remain on.

[@Enigma758]

@@nix324 Resistors not needed if in a push-pull configuration but he is using a single mosfet.

[@MaDnBaD]

@@Enigma758 no way! that's might be the reason why almost every mosfet ( even more durable and powerful) keeps dying in my case. I'm using the same circuit as in the video, with some modifications : thicker primary 6mm monolith to escape heating, 50kHz 0,33 nf capacitors on primary and stabilising capacitor on the input and 120 om resistor on PWM output. The peak I reached was around 190 watts with irf3205 with 10v D-to-S and 18 amps at 25 kHz. With active double fans capable of working around 10 mins nonstop. IRFZ44, irf1405, IRFP260m and many others die so fast not even getting closer. Actually one did, yet on low frequency around 7 kHz, but buzzing noise is unacceptable. Many other mosfets die on powering on in this circuit. If I got your idea right, there is a kind of capacitor in between gate and source of mosfet, so using it on a super high frequency with many amps delivery need an additional resistor to help it getting discharged faster? Zener diode can work as well?

[@emmanuelr6698]

Thanks, very interesting ! I used an audio spectrum analyzer to check the frequencies. It's funny because I could see all the harmonics, like for the 5 kHz, I saw 10 and 15 kHz peaks.

[@FarmingwithZana101]

Can you find the resonance frequency then use the frequency generator and put it on the resonance frequency

[@aboveaveragejoe6291]

Flyback transformers or horizontal output transformers were designed to run at 15750hz which was the horizontal frequency.

[@coucouj2781]

So does that mean at 1.57 khz, resonance is acheived and that the arc is at its greatest for that given voltage at the primary ?

[@aboveaveragejoe6291]

@@coucouj2781 it's 15.75khz and yes if the actual primary winding was being used. A transformer about that size would put out almost 30kv because their is also a built-in tripler .

[@coucouj2781]

…but in the experiment the arc seems to be greater at frequency below the 15 khz range ?

[@UserName-cb6jz]

​@@coucouj2781 What is important is the length of each pulse, not frequency. You could have one pulse each second, but its length would have to be no more than about few microseconds. A pulse charges the magnetic field, and when the pulse is off the magnetic field collapses very quickly producing high voltage. The energy contained in the primary pulse (current × voltage × time) determines the energy on the secondary.

[@nathanieljames7462]

I drive mine at 115khz and it rocks

[@ianhosier4042]

Add a feedback winding and a capacitor across the primary winding. The circuit self oscillates at the resonant frequency and the capacitor stops the mosfet from blowing up if the seckndary is open circuit.

[@jonlitchfield8888]

That pwm looks super handy. I wonder where to get one... i will not b lazy and go check provided vid link. Thankyou for sharing ludic i really love yr content

[@ludicscience]

Thanks!

[@mirzahosein2261]

a new idea in flyback drivers, thats great...

[@superdau]

Doesn't this kill the MOSFET quite quickly? If there is no way for a current to flow on the secondary side (e. g. no arc), where does the energy stored in the transformer go? Won't that create a huge voltage spike on the primary side?

[@ianhosier4042]

Put a capacitor across the primary winding if you don't want your MOSFET blowing up when the secondary is open circuit. Some put it across the mosfet but then you end up blowing the input capacitor and possibly your power supply.

[@nathanbunten4299]

Can you make a video with the frequency generator to a zvs? I am looking to get the frequency (sound) with a higher output voltage. Or would the frequency still be there if I added a voltage multiplier to the output of the fly back?

[@jonaoconnor8065]

Its possible did you make it?

[@jonaoconnor8065]

By interrupting the zvs output by a transistor driven by this pwm, is my plan, !!

[@nathanbunten4299]

@@jonaoconnor8065 yes i did

[@nathanbunten4299]

@@jonaoconnor8065 it is a little more than that. it overrides the frequency and sets a beat rate. I made a video with validation of what the circuit can do. kzbin.info/www/bejne/ZnyUYXqDncmDZsU

[@jatinkhajuria7151]

is it possible to produce music from arc

[@ludicscience]

Yes it is

[@jatinkhajuria7151]

How is there a video like this on your channel? Can you give me link?

[@balbal1497]

sir, the output of this high voltage flyback is AC or DC voltage output?

[@neutronenstern.]

Is it possible to reduce its noise, by instead of feeding it with a single frequency, feeding it with white noise?

[@_P0tat07_]

So what happens if you change the duty cycle?

[@igrewold]

I think the duty cycle acts as amperage=current there so + duty cycle % = + current & - duty cycle % = - current This based on my conclusion of running a led with pwm with arduino, maybe it is not right

[@nathanieljames7462]

You are expanding and collapsing a magnetic field. I go 50/50 to give the transistor(s) the most time for their on delay, rise time, off delay and fall time. Of course most chips can switch from 100s of khz to several mhz without issues except for optocouplers.... I drive my flyback at 115khz through an IGBT switched by a mosfet so there's compounding delays to consider

[@sidyajv]

Pls try ZVS driver.

[@benjaminvangheluwe3079]

Can the PWM generator be directly connect with a car battery?

[@nathanieljames7462]

Use PWM to drive a mosfet or IGBT connected to the car battery like he did.

[@trigger.warning]

where do you buy flyback transformers? i have one small one i got in a kit on ebay but i cant find any large ones.

[@ludicscience]

I got a bunch of flybacks from ebay several years ago. They are hard to find nowadays

[@gbhxn444]

can you make 1khz?

[@MaDnBaD]

my mosfet keep dying so fast.=( what's wrong might be?(

[@julian3bk]

Does the output voltage go down if you went even lower in frequency?

[@ludicscience]

Yes

[@kuhalaabd8156]

good evening the mosfet with circuit diagram no protection what do this problem

[@nathanieljames7462]

irfz44 has flyback diode

[@pounraj8355]

Is it okay to use 20volt as input?

[@MaDnBaD]

use as many as mosfet let's you

[@tajamulhassan6664]

Good excellent circuit

[@legpetruchka2124]

👍👍👍👍👍👍👍

[@UserName-cb6jz]

A whole minute advertisement in a 7-minute video?