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How can I make 3.3V DC from the 220V power lines without any transformer?

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Zedman

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Hi all,

anyone has any idea how could I make 3.3VDC from the 220V power lines without any transformer?
I need approx. 150 mA max.
Also the small (tiny) size is very important.
Are there any ICs out there for this?

thanks,
Zedman

Added after 5 hours 54 minutes:

Forget it, i've found the solution.
 

smallest 220v to 5v transformer

do u want isolation.

quality and effeciency expectation?
 

bp5041 circuit

I just haven't used g(o)(o)gle, I've found many implementations with capacitors and even resistance based ones.
I think I'll do capacitive type one it shown it only provides about 20 mA, but in peak i think it can handle 100mA to switch on/off an 5V relay.

I'll try to put on a 3.3V stabilizer instead of the zener, altough I've found a microchip article which is talkin' about using 5V1 zeners only.

Added after 9 minutes:

I've found I'll use a small 12x9x6mm 600ohm isolator transformer too.
 

simple 3.3v relay

One of the considerations with not using a transformer is safety. This might be a little oddball, but you could always use a 220-volt, (or two 110-volt in series), small light bulbs, shining onto a small array of solar cells arranged in whatever series/parallel configuration that gets you the voltage and current you need.

Like I said - oddball - but it does provide absolute line isolation and safety. Plus it does the AC-to-DC conversion in one device.
 

astec da2-3101

Zedman, If you now intend to use isolation transformer, why aren't you use a step down transformer?. Because the size will be the same for the same amount of power. ( what do you mean by 600ohm transformer? I hope this is not an audio transformer and you are talking about power transformer with 1:1 ratio)
 

schematic 220v to 5v 1a

Khabree, I've lost one already, burn burn burn :)) this one: SM-LP-5001 (it's completely unusable here?)

Seriously, i've built this: **broken link removed**

It does show the 3.3v output, BUT it's definiately not good, or I made some mistake.
The 2 Zeners on the input of the Bridge gets hot like hell, the bridge itself gets hot, and the zener on the output gets hot too. Not warm, hot.

I would like to put this and the small circuit what it will supply behind the plug or switch on the wall, so absolutely NO heat allowed.

That's how it should work or I did something wrong?

Added after 3 minutes:

I tried that schematic, because microchip AN talks about using one period of the 220V sine wave only which leads to the half of the available current on the output.

Added after 8 minutes:

Are there step-down transformers with the same size like the one I've burnt? (12x9x6mm)

Added after 11 minutes:

I have a charger for my Nokia phone which outputs 5.7V / 800mA but it's so light and slim, but i can't open it because i haven't got the right torx screwdriver... :(

Added after 5 minutes:

Hmm, charger it's not the way I think because it's a switch mode psu, an it may interfere with my circuit.
 

3,3v stabilizer

charger (switch mode psu) will not interfere with your circuit.
 

220v to 5v schematic

It's a ~800MHz RF transceiver, data rate will be around 50kbps that's why i have doubts...
Anyway sm psu won't fit the size requirements I think.
 

220v 3.3v

use smps charger for relay and use resistor and 3V3 zener for rest of the circuit.
 

sm-lp-5001 600ohm

Currently I can't see what's inside the Nokia charger which itself too big to fit in.
But anyway with the resistor / zener combo the heat problem came up what I described earlier...
 

3.3 v from 220 v

i use Astec DA2-3101 which is 4,8 x 1,1 x 2,2/3,9 cm (pcb)
when you cut and bend part of pcb that is in plug it is 4,8 x 1,8 x 2,2 cm.
provides 5V/1A.

Added after 5 minutes:

resistor & zener 3v3 to make 3,3 volts from 5,7volts .
 

da2-3101 usa or canada

That's cool, but I have a round shaped hole in the wall which is sized for commercial plugs and switches and I already have a 20x25 mm pcb which has to be hid into that hole and powered somehow...
The psu' pcb should be around 35-40x20mm and it should be flat...
 

da2-3101 forum usa or canada

ok.
how about ROHM dc/dc hybrid module (small sip10 package) BP5040 or BP5041?

all you need is bridge rectifier and capacitor to make dc voltage at input
 

dc in 3.3v

That's looks promising, I checked in the shops here and they do not have this. Damn.
Any replacement type?
 

switching 220 3.3

Hungary,

look at this: **broken link removed**

that's 5cm long but if I could get one...

Added after 1 minutes:

Price is $15

Added after 1 minutes:

The Capacitor/Resistor/Zener combo would beat that price well... the complete RF thing is cheaper...
 

zener 3v3

but Hungary=EU, you can order something like rohm module from farnell or rs-components or ...
check at
farnellinone.com
distrelec.de
rsonline.de


if you change relay, 5V-coil draws much current, to 24 or 48V you will get
better ratio (relay energized or not) and avoid heat of zeners in relay-off state.
(transformerless psu).
 

da2-3101 схема

I wanted to use latching type relay, and later Triacs.

Anyone else could tell why the transformerless thing heats too much?

Added after 40 seconds:

thanks for the help guja
 

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