I am a little confused (nothing new!) Are all the power commons intended to be referenced to earth ground as shown?
And all referenced to each other?
Max.

 

I am a little confused (nothing new!) Are all the power commons intended to be referenced to earth ground as shown?
And all referenced to each other?
Max.

That's my interpretation.

 

If this is so, what makes it any different or safer than one with no galvanic isolation?
Max.

 

I am not done with this schematic additional revisions will be forthcoming, includun a regulation mecanism using a DC op amp, I always listen to feedback. I came to AAC originally to learn new thing, and I haven't stopped yet. It can be depressing to always shut down threads due to transformerless power supplies( a rule I agree with 100%) so decided to be proactive and show a method that will pass muster here. Which seems to me to be a good alternative instead.The fact ids Q1 andQ2 will never go below ground so a capacitor may be safely eliminated as many have pointed out.

 

The fact is there is a transformer in the circuit, and it is stated in no uncertain terms the dangers involved, You are not going to create high voltage with substantial currents without some risks. There are many projects if you have to ask how to do it you should not be doing it. This is why we have moderators here, to judge such situations. I still remember a post from a 12 year old how to electrify a door bell with 220VAC for yucks. I have made Transformerless power supplies that were safe, and had no problems doing so in my professional career, it was in an enclosed space with open 220VAC all around I was careful to document it completely as only a tech like me would ever be in that cabinet.

AAC does not ban working with line voltages, we just insist it is done safely.

 

@Dzoro @bertus One of the frequent threads we moderators frequently have to shut down is transformerless power supplies to create high DC voltages. I have decided to show one way to do this that meets AAC TOS and COD ( Terms of Service and Code of Conduct .

What is the PWM topology?
It is not the typical PWM Half-Bridge.
Your circuit does not have the typical Two Capacitor Voltage Divider connected to the other side of the Primary.
I think, your circuit is called an Asymmetric PWM Half-Bridge PWM converter or a Soft-Switched Half-Bridge PWM converter design.

 

For what it's worth, here's a similar inverter power supply I built recently for an EL project. Changing Vcc gives some degree of variability of the output HV, as does adjusting the size of the coupling capacitor C6 or of course the transformer rating. I didn't really design this with variable voltage in mind, so it's probably not as widely variable as the circuit @Wendy provided. Still, I've run it with Vcc ranging from ~6V (a 9-volt battery) to 19V (a laptop power brick).

Some notable differences versus the circuit in #1 are that I used an op-amp U1a to generate my square wave instead of a 555. Also, I wanted to use N-channel MOSFETs for the power switching, and that meant I needed a bootstrapped voltage to drive the high-side switch. That's what the other half of the dual op-amp U1b oscillator does, using the charge pump voltage doubler comprised of Schottky diodes D1 and D2, capacitors C4 and C5. Another consequence of sticking with N-channel MOSFETs was that I needed Q1 to reverse the logic applied to the high side gate relative to the low side.

The transformer is a wall-wart run in reverse. (R1 doesn't exist, but helps the simulation.)

 

What is the PWM topology?
It is not the typical PWM Half-Bridge.
Your circuit does not have the typical Two Capacitor Voltage Divider connected to the other side of the Primary.
I think, your circuit is called an Asymmetric PWM Half-Bridge PWM converter or a Soft-Switched Half-Bridge PWM converter design.

no PWM, It isn't necessary, just a 555 astable making a 50% duty cycle 60 Hz square wave The peak to peak voltage of the 7555 is a direct function of its power supply voltage. The design is similar to one Tony Van Roon came up with. but I have added some twists. Tony's design used a low pass filter to attempt to make a usable AC inverter.

 

Schematic has been updated, C5 eliminated. I will now use the second post I reserved to show the regulated version I have in mind, it won't happen overnight, but it will happen.