140V miniature power supply

[BrianDonegan]

You could use a dual-primary transformer rated at, say, 30V+30V, then wire the primaries as if for 110V, but connect it to 220V. Wire the resulting 60V secondaries in series and you have 120V. Then it's just a bridge and an LM317 and a few parts to bring it down to 100V.

 

[darkfenriz]

Not exaclty.
Please refer to page 6 of the datasheet, where you can see the MC34063 driving an esternal transistor.

OK, at the schematic on the datasheet the driver transistor is connected to switching node, so the limitation is here. One surely could rearrange it so that no pin of MC34... experiencesanything above 12V.


Off topic: how did you rectify 4,5kV? series thyristors? SiC diodes? thyratrons?

 

[RJM1]

 

[stratus46]

You could use a dual-primary transformer rated at, say, 30V+30V, then wire the primaries as if for 110V, but connect it to 220V. Wire the resulting 60V secondaries in series and you have 120V. Then it's just a bridge and an LM317 and a few parts to bring it down to 100V.

It would work for a few seconds until the transformer fails. Doubling the Voltage will likely saturate the core and the current will go way up and fail.

Explained here. Look for 'Circuit Effects of Saturation'
Understanding Transformers: Characteristics and Limitations

Is this too large?
http://www.antekinc.com/pdf/AS-05T120.pdf

G²

 

[woody]

What about using a 220 to 24 transformer then run the 24v into a the secondary of
a 220 to 12 transformer to get about 110 vac. But are you sure you can't find any small 220 to 110 transformers or even a small 220 to 440. Or you could use a 220 to
55 or 60v transformer and use a voltage doubler.

 

[AndrewT]

Of course, a 30VA, 25+25Vac, with voltage doubler, for the low current demand.

 

[Atilla]

That Antec is looking very good, I might end up trying one, but for a different project. 1kg worth of transformer is a bit too much in this case.

 

[quadtech]

Here are a few links to help you. You should be able to tweak
all of them to output 140V.

Nick DeSmith design is one of the most efficient ones, based on
the MAX1771.
Mike Mooress (threeneurons) has an excellent MC34063 design.

Tayloredge is one of the best ones you can pick ready made.
John Taylor also put up a nice comparison of nixie supplies available.

Nixie HV Switching PSU
Nixie Stuff Threeneuron's Pile o'Poo

Mike's supply on ebay -

http://www.ebay.com/itm/150642015998

Tayloredge - Smart Nixie modular display system

http://www.tayloredge.com/storefront/SmartNixie/PSU/comparison.html

Tayloredge - High current nixie power supply

 

[quadtech]

Here's another off the shelf option -

Nixie Power supply, High Voltage Switch Mode DC-DC Converter Kit, 95-190VDC, 25ma @ 180VDC HV-SMPS - All Spectrum Electronics

 

[TechGuy]

Here you go:
Low Profile DC-DC Converters Surface Mount Section

or try here:
EMCO High Voltage Power Supply Manufacturer

Alternatively you can search for LCD fluorescent backlight power supply which also provide about 140V in small packages. They can be usually found on surplus electronic sites (ie electronics goldmine).

 

[Atilla]

Nice, TechGuy, very nice. Those are awesome.

I got a simple 555 based circuit for experimenting, but the Picoelectronics and EMCO modules look *perfect* for integrating in small space.

 

[Atilla]

Thanks for all the help guys.

Now, I just have to remember that those can bite. Left hand behind my back and don't even look at the capacitors in a funny way.