Sonsivri
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
December 09, 2016, 12:48:46 00:48


Login with username, password and session length


Pages: [1]
Print
Author Topic: power supply without a transformer  (Read 4038 times)
0 Members and 1 Guest are viewing this topic.
mr_byte31
Hero Member
*****
Offline Offline

Posts: 544

Thank You
-Given: 49
-Receive: 144



« on: January 08, 2008, 07:43:01 19:43 »

hi
i want to design a supply without using a transformer
the supply is 220/12
i thought to but a rectifier then a resistor then a zener 9v
what i want to know does the supply can supply much current
and is it stable
Logged

Do not trifle with the Moderators , as you are small, and crunchy, and taste good with ketchup.
Faros
Senior Member
****
Offline Offline

Posts: 253

Thank You
-Given: 125
-Receive: 178


« Reply #1 on: January 08, 2008, 11:08:34 23:08 »

http://www.sonsivri.com/forum/index.php?topic=9126.0
Logged
alliegro
Guest
« Reply #2 on: January 09, 2008, 05:45:43 05:45 »

Transformer less power supply can provide upto(normally) 50ma of current. But be warned that there is NO ISOLATION. Also the regulation of the circuit is not very good. The mains power is taken through a capacitor (usually .47uf to 1uf) of atleast twice the AC mains voltage. Then the bridge rectifier of suitable rating as above,then the zener and capacitor at the output of the bridge. Usually the voltage is from 5V to 18V as desired by the Zener diode.
Logged
irvinos
Newbie
*
Offline Offline

Posts: 11

Thank You
-Given: 13
-Receive: 21


« Reply #3 on: January 22, 2008, 09:02:54 21:02 »

Transformerless power supplies can be fatal. BTW the most important subject is current. How many current has been drawn?
Logged
tantino
Newbie
*
Offline Offline

Posts: 9

Thank You
-Given: 6
-Receive: 1


« Reply #4 on: January 25, 2008, 05:32:37 17:32 »

Have a look at www.national.com or www.linear.com they have simple switchers and software tools that make power supply design so much easier
Logged
trapperxxx
Newbie
*
Offline Offline

Posts: 16

Thank You
-Given: 40
-Receive: 3


« Reply #5 on: February 14, 2008, 08:46:09 08:46 »

u can use power integration tiny switch..(lnk304-306)
12v 50ma--300ma
Application Note AN-37
and chechk this link
http://www.powerint.com/PDFFiles/lnk302_304-306.pdf
Logged
chen
Junior Member
**
Offline Offline

Posts: 59

Thank You
-Given: 2
-Receive: 5



« Reply #6 on: February 14, 2008, 03:46:08 15:46 »

u can use power integration tiny switch..(lnk304-306)
12v 50ma--300ma
Application Note AN-37
and chechk this link
http://www.powerint.com/PDFFiles/lnk302_304-306.pdf

is it possible to increase the current capacity of  the supply & how?
Logged
trapperxxx
Newbie
*
Offline Offline

Posts: 16

Thank You
-Given: 40
-Receive: 3


« Reply #7 on: February 21, 2008, 04:28:34 16:28 »

I never use this curcuit..but u want to more current, you must fly back..and transformer Sad

....I used lnk363pn 400mA in 5V and other channel 12V 100mA, everything is good .. and very little transformer ee16...
Logged
ambo
Newbie
*
 Muted
Offline Offline

Posts: 23

Thank You
-Given: 112
-Receive: 6


« Reply #8 on: March 25, 2008, 05:52:07 17:52 »

Microchip has an application note for this ....powering up a pic mcu w/o any transformer or transformerless power supply.  Cant remember the xact an number but just do a quick search for transformerless power supply in microchip website and youre sure to find it.
Logged
sisar
Inactive

 Muted
Offline Offline

Posts: 2

Thank You
-Given: 2
-Receive: 1


« Reply #9 on: April 03, 2008, 12:35:20 00:35 »

I found many industrial applications that use this type of transformerless power supply, like timers, but they tend to break very often, especially if u use a generator in case of power cuts or if there is a high noise on the line
Logged
ekinci
Guest
« Reply #10 on: April 03, 2008, 09:58:18 09:58 »

in a transformerless power supply maximum current you can get is around 200 mA
Logged
pongsak.swf
Guest
« Reply #11 on: April 04, 2008, 12:22:48 12:22 »

You use TOP221
Logged
carlao
Guest
« Reply #12 on: April 07, 2008, 04:37:14 04:37 »

Transformerless power supply can be done, until 50mA output. But, is important to keep same (or almost same) load in the output, to get some regulation in the output voltage.
If you deceide use SMPS, one option ins L6565N, from ST.

Posted on: April 07, 2008, 04:36:04 04:36 - Automerged

sorry: the L6565N use ans EXTERNAL mosfet.
For low power, use VIPer family, from ST.
Logged
Pages: [1]
Print
Jump to:  


DISCLAIMER
WE DONT HOST ANY ILLEGAL FILES ON THE SERVER
USE CONTACT US TO REPORT ILLEGAL FILES
ADMINISTRATORS CANNOT BE HELD RESPONSIBLE FOR USERS POSTS AND LINKS

... Copyright 2003-2999 Sonsivri.to ...
Powered by SMF 1.1.18 | SMF © 2006-2009, Simple Machines LLC | HarzeM Dilber MC