HELP WITH HIGH POWER SUPPLY

[MrThe50sanchez]

Hello Everyone!

Im just building a high booster voltage converter implementing Fly-back converter theory using LT1308B and also triple voltage circuit.

I want to start with a small amount of voltage (CR2  3V 850 mAh or litium batery 3,7 1,8Ah) and get to 180v to light up a Nixie tube. the thing is that I don´t know how to get the 180V by starting with this little voltage.

                                                3V ---- transformer (1:12) ---- I get 36v ---- triple voltage converter (36v · 3 = 108v) --- not enought to light up a nixie tube.

Any Ideas how to get those 62V to get to 170v? bigger transformer? or implementing a quadruple voltage circuit?

Thanks a lot!

[Paul Andrews]

This design works by inducing a voltage in the primary when the current flowing through it is turned off. The voltage induced doesn't have much to do with Vin, It has more to do with how long the current is allowed to flow.

[gregebert]

The voltage tripler as shown requires symmetric positive and negative cycles. The flyback topology you are using is primarily unipolar, so it wont produce the symmetric positive and negative cycles like a line-powered transformer does.

If you are going to use a flyback topology with a voltage multiplier, you will need a center-tapped primary winding, and two switches that alternately power the transformer. I'm fairly certain the LT1308 wont work in that application. 

[newxito]

There is a schematic of a high voltage supply (350V, 1.2mA) in the LT1308 datasheet, so maybe you can modify the circuit (FB voltage divider resistors ) to get 170V at 2.5mA, that should be enough current for one 1N16.

If you need more current, have a look at the LT3757 in flyback mode.

[Toby Thain]

On 2020-05-14 11:35 AM, newxito wrote:
> There is a schematic of a high voltage supply (350V, 1.2mA) in the
> LT1308 datasheet, so maybe you can modify the circuit (FB voltage

The problem with a lot of datasheet designs is that the transformers are
long unobtainable. (Also I don't see that circuit in the LT1308
datasheets that are online.)

If you want a quick solution, there are a LOT of simple, cheap DC
supplies covering this range on ebay:

e.g.
https://www.ebay.ca/itm/High-voltage-power-supply-module-kit-DIY-for-Nixie-tubes/261169220982
at < US $8 each

--Toby

> divider resistors ) to get 170V at 2.5mA, that should be enough current
> for one 1N16.
> If you need more current, have a look at the LT3757 in flyback mode.
>

> --
> You received this message because you are subscribed to the Google
> Groups "neonixie-l" group.
> To unsubscribe from this group and stop receiving emails from it, send
> an email to neonixie-l+...@googlegroups.com
> <mailto:neonixie-l+...@googlegroups.com>.
> To view this discussion on the web, visit
> https://groups.google.com/d/msgid/neonixie-l/41554687-014e-4f4b-bc08-1f46f7b6812c%40googlegroups.com
> <https://groups.google.com/d/msgid/neonixie-l/41554687-014e-4f4b-bc08-1f46f7b6812c%40googlegroups.com?utm_medium=email&utm_source=footer>.

[Bill van Dijk]

Anyone interested in playing with PIC devices may want to take a look at the Microchip AppNote TB053. It describes (in great detail) how to use a PIC16C781 for a boost converter producing a regulated 170V at about 2W from 9V DC. It is a fairly simple solution which is easily ported to other PICs, and with some more effort to other brand MPUs. The beauty is that if you have spare resources in your device MPU, you can add this functionality right in.

https://www.microchip.com/wwwAppNotes/AppNotes.aspx?appnote=en011970

Bill

To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a0a23d28-315f-4789-4e46-b0fcff094b04%40telegraphics.com.au.

[newxito]

You can find the schematic in the LT1308A/LT1308B datasheet.

[MrThe50sanchez .]

Hello! thanks for the answer.

Wow, I thought that the most important think was the Vin voltage so the turn ratio of the transformer can high up with the kick. So, is there anywhere that I can see with how much current goes to the Vin , how much voltage do Im going to get at the seecundary?

thanks a lot.

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a52abb77-e3d2-4a12-b8b5-98b37102da48%40googlegroups.com.

[MrThe50sanchez .]

Hello!

So sorry that I putted in the wiring diagram the capacitors without the positive and negative pins. As I searched, yes, they need to be with polarity for the cicles high up the voltage in every step.

About the transformer, The LT1308B does have the pin SW so when it is on, It give`s the switching mode to the primary of the transformer, so it can generate that voltage kick in the secondary (as I understand), I woud search more info about the "Center-tapped primary winding".

Thanks a Lot!

El jue., 14 may. 2020 a las 17:18, gregebert (<greg...@hotmail.com>) escribió:

The voltage tripler as shown requires symmetric positive and negative cycles. The flyback topology you are using is primarily unipolar, so it wont produce the symmetric positive and negative cycles like a line-powered transformer does.

If you are going to use a flyback topology with a voltage multiplier, you will need a center-tapped primary winding, and two switches that alternately power the transformer. I'm fairly certain the LT1308 wont work in that application. 

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/36df2a48-2eb0-4f7c-9846-2b441ed08812%40googlegroups.com.

[MrThe50sanchez .]

Hello!

Wow, I was looking a lot to the datasheet but just the first schematic It appeared, Just going to study the one you just said, It looks really good.

Thanks a lot,

best regards from Spain.

El jue., 14 may. 2020 a las 17:35, newxito (<axt...@gmail.com>) escribió:

There is a schematic of a high voltage supply (350V, 1.2mA) in the LT1308 datasheet, so maybe you can modify the circuit (FB voltage divider resistors ) to get 170V at 2.5mA, that should be enough current for one 1N16.

If you need more current, have a look at the LT3757 in flyback mode.

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/41554687-014e-4f4b-bc08-1f46f7b6812c%40googlegroups.com.

[MrThe50sanchez .]

Ei!

Thanks, going to take a look at it!

thanks a lot!

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/00d001d62a10%2498b23ef0%24ca16bcd0%24%40gmail.com.