Converting 110Vac to 220Vac

[Vindhyachal.takniki]

1. I have made a circuit operating from 220Vac/50Hz. It had capacitive supply to power up the microcontroller, which inturn controls the triac to switch 220Vac/50Hz to heating wire which is resistive in nature.
heating wire is resistive, which consumes 70W on 220Vac/50Hz.

2. Now I am checing some possibility if same circuit can work on 110Vac/60Hz. I think same capacitive supply can work(that I will check), but heating wire will not get heat up from 110Vac/60Hz, as it gets heat up at 220Vac/50Hz.

3. I am searching for some very light weight circuit which can do this. As this needs to be fit inside a handheld remote.
First thought was to use a transformer, but it will be bulky.

4. I think frequency does not affect much, as capacitive ckt will work fine & load is also resistive

5. Any ckt suggestion on this, On google I mainly found transformer based ckt or i am searching with wrong keywords

[Zero999]

Since the heating element is resistive, the frequency is unimportant. You could build an electronic transformer, similar to the type used for halogen lamps to power the heating element. The circuit can be found using a search engine, or you could modify an off the shelf electronic halogen lamp transformer by rewinding the secondary. An alternative to that is to convert the 120VAC to 220VDC, which you might be able to find an off the shelf solution for.

The microcontroller power supply, just needs a capacitor with twice the value and half the voltage, although it will be double the physical size, with everything else remaining equal.

[Codebird]

There's no room for a transformer, and the heater draws too much current for a voltage doubler. Maybe rectify the input into DC, then feed it into a boost converter or h-bridge and high-frequency transformer. That could work.

Have you considered just replacing the heating element?

[Ian.M]

Use two identical 110V heating elements (i.e. split your existing wire in two of half the length, unless its trace heating cable with a distributed resistor between its two conductors, which you'll need to get with a 110V rating ).  Fuse each element at 1.5x nominal current.

Wire in series for 220V or in parallel for 110V using a DPDT switch to select the voltage.
The wattage will remain the same. 

If the lUser selects 110V with a 220V supply the fuses will blow if the power level is above 40%.  Make sure the TRIAC is rated for a x5 overload so the fuses blow first.

If they select 220V with a 110V supply it simply wont get hot enough (quarter power).

[Zero999]

I agree: replace the heating element with one rated for the correct voltage.

Note that there isn't room for a heavy mains transformer but the electronic halogen lamp transformer I refereed to, works at a higher frequency and is extremely light weight. I just had a Google and it's not easy to find units designed for 120V operation. Here's one.
https://www.amazon.com/Pack-20-105W-Dimmable-Transformer-approved/dp/B0053V1MLC#

If you don't want to rewind the secondary to 220V (if you do, please change the label, to stop someone else finding it and believing the output is 12V!), you could make your own 12V to 220V high frequency transformer and connect it to the secondary.

[Brumby]

For the microcontroller, the solution is simple.  Low power, low voltage ... no problem.

But for the heating side of things, you can't beat this for simplicity, effectiveness, safety and reliability:

Use two identical 110V heating elements (i.e. split your existing wire in two of half the length, unless its trace heating cable with a distributed resistor between its two conductors, which you'll need to get with a 110V rating ).  Fuse each element at 1.5x nominal current.

Wire in series for 220V or in parallel for 110V using a DPDT switch to select the voltage.
The wattage will remain the same. 

If the lUser selects 110V with a 220V supply the fuses will blow if the power level is above 40%.  Make sure the TRIAC is rated for a x5 overload so the fuses blow first.

If they select 220V with a 110V supply it simply wont get hot enough (quarter power).

Trying to wrangle 70W through mains level voltage conversion is not impossible at all, but for the size constraint presented - it is a challenging route to take.

The KISS principle has lasted well because there is sense and practicality in it.

[tooki]

FYI, it's 120V, not 110V. Hasn't been 110V for many, many decades.

[Zero999]

FYI, it's 120V, not 110V. Hasn't been 110V for many, many decades.

Yes. I did some Googling and found this post, which is interesting.
https://www.quora.com/Is-the-power-system-in-the-US-technically-110-115-or-120VAC-How-about-220-or-is-it-240-or-235VAC

So far, everyone's presumed that the voltage is fixed but could it vary? If so go for a 120VDC element and use a switched mode power supply with a universal 100V to 250VAC input. You could also consider a 240V element and 240VDC output, universal input SMPS but that will be much more difficult to find.