Design Transformerless Power Supply

[bluethunder7000]

transformerless power supply

I need help to calculate the current in each branch of the attached circuit

and i need some answer for :

1:how can i know the max. output ampere from this circuit?
2:if i need more than the expected output current what i should doing in this circuit?
3: i built this ct. on board and it work fine ( giving a 33Vdc Output ) but when i change the capacitor to 2.2µF/275Vac the resistor 100Ω/3watt be warm quikly and burned after few min. So if i need to change the capacitor what i should be doing in the all circuit?
4:when i need to let this circuit to withstand the input voltage from (220 to 350 Vac) Phase to neutral what should i do to make this feature?
5:how can calculate the power of this ct.?
6:when i design any ct. what is the best program which can i use to draw & simulate the circuit and get a very exact results as the real calculations on board?

I really appreciate youe help me in this design
thanks again

 

[IanP]

transformerless power supply circuit

I would remove R2 from the circuit, reduce the value of R1 to, say 10Ω (it basically works as a fuse) as you want to drop voltage on a heat-less capacitor, and replace D1-D2 with a full bridge. By doing this you will not shorten every second half of the sine wave on diode D2 ..
To calculate available current in the circuit use normal Ohm Law and replace R with Zc=1/2Π*f*C ..
To withstand high voltage range use two capacitors rated for 275Vac connected in series with parallel equalizing resistors. Also, you may need to increase current capacity through the shunt regulator (in this circuit this is the zener diode) by adding a power transistor which together with this zener diode will form a very powerfull shunt regulator ..
Regards,
IanP

 

[vicky]

transformerless power supply design

in start you use a npn transistor forthis purpose with a bridge

 

[zenisle]

transformerless power supply circuits

can you put the circuit in front of the page.

 

[bluethunder7000]

transformerless powersupply

hi

how can i put the circuit in front of the page , i tried and i don't know how

thanks

 

[nikhilele]

transformerless power supplies

zenisle Posted:
can you put the circuit in front of the page.

bluethunder7000 Posted: 
how can i put the circuit in front of the page , i tried and i don't know how

just open acrobat press G or select graphics selet tool and cut out the desire portion as i have done for you.

 

[mighty12]

im very much interested in this topic...... i would like to know how can i use transistor to increase the current capacity of the of the shunt regulator.???? thnx in advance..

 

[MiKatp]

Hello all, this is my first post.

I have a small question about the schematics above. I'd like to know what for is D2?

I am studying several examples of transformerless power supplies, like the one in https://ww1.microchip.com/downloads/en/AppNotes/40171a.pdf. But, if you look at AN954 from Microchip (Transformerless Power Supplies: Resistive and Capacitive), it does not use that diode.

Thank you.

 

[JStuffer]

Hi, I raped the image so it reflects some of the other folks' previous recommendations plus some thoughts of my own. It's not perfect and it's NOT how the circuit's final version should look like. If you have something to say to correct it, please do so!

Note, that I didn't change the R1 and C1 values, as I'm not sure how they should be.

Please be careful putting this together; use only a safe capacitor for C1 (such as X2 class), make the isolating distances sufficient and don't electrocute yourself!

JS.