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Tiny Low Voltage/Amperage/Wattage High Frequency 110V Inverter

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thebailey

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Hey guys, thank god for this site, feel like I haven't slept in 2 days trying to answer this problem via google, no joy, but I know you guys will have the answer. I'm not too bad at electronics, soldered together a nixie clock or two, a jacobs ladder, can get my head around a 555 timer, can solder without killing a transistor, but always have to look up which end is the collector and which is the base ;)

My project is this: I want the smallest possible 110VAC power supply, best specs would be:
Input: 1.0V - 14V DC (Maximum flexibility of NiMh / LiIon / Car12V)
Output: 100V - 240V AC @ 40ma (5-10W) @ Any Hz (highest efficiency)
Size: Smaller than 1" x 1" x 0.5" (2cm x 2cm x 2cm would be fine also?)
Efficiency: >90%

I would accept:
Input 2.5V - 4.2V DC (Lithium primary or LiIon)
Output: 110VAC @ 40ma (5W)
Size: 2" x 2" x 1" (5cm x 5cm x 2.5cm")
Efficiency: >50%

The purpose of this circuit would be many and varied (I have lots of nixie / neon / HV projects to drive from small batteries), but this specific project I'd be looking to make 10 tiny bases for some 1970s neon bulbs, to make them look as if they were lit by nothing (5W each).

I've disassembled some disposable cameras and tried those, but any more than 2V and they seem to overheat, and the wattage seems to be 0.5W max for the poor transistor before he lets out his magic smoke. But I have plenty of those little transformers/transistors (anyone know what the max wattage for those transformers is?). I would LOVE if someone had invented a transformerless IC I could use, even if it needed an external inductor.

Thanks guys!
 
Hi. :)

Thebailey said:
...
... but this specific project I'd be looking to make 10 tiny bases for some 1970s neon bulbs, to make them look as if they were lit by nothing (5W each).
...

Sounds like a fun project. To run the 5W neon bulb it's probably best to generate the voltage and current required by the bulb, not try to make a "generalised" inverter.

There are quite a few low power inverter circuits to run 4W fluorescent tubes, these would probably run your 5W neon bulb quite well and may only require a slight adjustment in the number of turns on the transformer coil to make it optimal.

I've seen fluoro inverter circuits using only 2 transistors and a coil and a few resistors, caps etc, which you should be able to build if you could build 555 circuits and Jacob's Ladders.
 
Hey guys, thank god for this site, feel like I haven't slept in 2 days trying to answer this problem via google, no joy, but I know you guys will have the answer. I'm not too bad at electronics, soldered together a nixie clock or two, a jacobs ladder, can get my head around a 555 timer, can solder without killing a transistor, but always have to look up which end is the collector and which is the base ;)

My project is this: I want the smallest possible 110VAC power supply, best specs would be:
Input: 1.0V - 14V DC (Maximum flexibility of NiMh / LiIon / Car12V)
Output: 100V - 240V AC @ 40ma (5-10W) @ Any Hz (highest efficiency)
Size: Smaller than 1" x 1" x 0.5" (2cm x 2cm x 2cm would be fine also?)
Efficiency: >90%

I would accept:
Input 2.5V - 4.2V DC (Lithium primary or LiIon)
Output: 110VAC @ 40ma (5W)
Size: 2" x 2" x 1" (5cm x 5cm x 2.5cm")
Efficiency: >50%

The purpose of this circuit would be many and varied (I have lots of nixie / neon / HV projects to drive from small batteries), but this specific project I'd be looking to make 10 tiny bases for some 1970s neon bulbs, to make them look as if they were lit by nothing (5W each).

I've disassembled some disposable cameras and tried those, but any more than 2V and they seem to overheat, and the wattage seems to be 0.5W max for the poor transistor before he lets out his magic smoke. But I have plenty of those little transformers/transistors (anyone know what the max wattage for those transformers is?). I would LOVE if someone had invented a transformerless IC I could use, even if it needed an external inductor.

Thanks guys!

One of the biggest problems with your requirement will be the 1 to 14 Vin. Not only is that a really wide range (percentage wise,) but there are not many power circuits that will run on 1 volt.

Also, even at 100% efficiency, 5 watts out would need 5 amps in at one volt.
 
A PICAXE micro can run from 1.8 to 3.6 volts. https://www.electro-tech-online.com/custompdfs/2012/07/picaxex2.pdf. The TI MSP430 will also run at those voltages. So, get yourself a buck/boost design that can handle your input. Here is a 1.8-5.5 V input buck/boost converter. https://www.linear.com/product/LTC3113 Once you get a decent voltage, drop it down to 3.3 V. Use the PICAXE to generate 2 out of phase signals and use a center tapped xfomer with the correct ratio. The primary is center tap to ground and the ends go to 2 switches. Watch the losses.

There is no reason why you can't rectify the output and optically couple it back to the micro to do regulation. i.e. PWM the primary of the transformer.
 
Thanks for the assistance guys, I've check out those links, and they are great options, but I've found/bought this to give it a try, and it's fantastic!
**broken link removed**
$15 for something that accepts 2V - 16V and can produce 120VDC -250VDC at up to 12W according to its maker at https://www.tayloredge.com and best of all, it's absolutely tiny!

I presume we can't find a smaller/cheaper solution than that, so now I just need to turn it into AC - he says I need an H-bridge, does anyone know of a 250V 15W H-bridge that's small/efficient, and how to rig it up?

Cheers!
 
Do you need ac? maybe it would look funny with only one "leg" on all the time?
If ac some kind of oscillator and an h bridge. Let me see whats small at 250 volts.
 
Just build or buy a 4W fluoro tube inverter as i said before, they always output AC and are cheap and simple. If you are google searching then "camping light circuit" will also find some simple small fluoro inverters as 4W tubes were common on little camping lanterns.
 
Ok, so there's an advantage to transformerless circuits, they're tiny and efficient, so if possible, that's what I want to build. I do have a dozen tiny transformers from disposable cameras (perhaps flyback?) but they turn 1.5V into 200-400V, so could they be reused without rewinding, and can they handle 5W? It needs to be full grid 100-120VAC at 40-50ma, so I think that's a sinewave going positive 170V to negative 170V peak to peak in ideal conditions, but a square wave of 150V +/- should work just as well. I'll keep googling "camping light circuit" and see what I can find unless somebody can find a way to invert the polarity of 150-200VDC at least 50 times a second (my hands aren't that fast) ;)

Here is a simple example of an inductor based inverter, and it can be so simple and so small while being high efficiency: https://www.nerdkits.com/videos/backlight/
 
Sorry to say but I very much doubt those camera transformers would handle 5W continuous.

Those cheap Asian made "camping lanterns" on ebay are often the type with 4W fluoro tubes, maybe you could buy a cheap one and pull the little inverter PCB out? I think they are not much more than a couple of transistors and a small transformer.
 
I've had a quick search on eBay, but can't seem to find any that ship to Australia? Be grateful if you could find a link.

It's so simple to make 200V from any DC power source, I can't believe there's not already a simple way to make it into AC from there!
 
@KISS Wow those devices are amazing, if they'll let me order a few I'll get them for another project, thanks! SO annoying that they A) Are 1.5W max, not 5W, and B) Internally reate AC, but then don't give you an AC output before rectifying back to DC. Oh well, it's probably just pulsed DC (0V to XXXV) not true AC (-XXXV to +XXXV)
 
I'll email those people and see if they make devices more suited to my application, keep any ideas like that coming guys!
 
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