In this article we study a simple flyback converter design which is implemented as an SMPS 12V, 5amp battery charger power supply.
How it Works
The proposed 12V, 5 amp smps battery charger circuit employs a flyback converter topology which results in the required smps based high current, compact, mains isolated converter design.
Here, the a high power mosfet becomes the main switching component and is used for triggering the ferrite primary winding with the set high frequency mains rectified Dc.
When switched ON, the 470k resistor charges the mosfet gate into conduction and initiates the switching action.
The above action induces a voltage across the auxiliary winding of the transformer which results in a feedback voltage to the mosfet gate via the 2n2/100V capacitor forcing the mosfet to conduct even harder.
As soon as this happens, the primary winding gets connected with the full 310V DC rectified voltage via the mosfet drain/source terminals.
During this process, the voltage across the 0.22 ohm resistor situated at the mosfet source tends to cross the 0.6V level, which instantly triggers the transistor BC546, which shorts the gate of the mosfet to ground, rendering it completely switched OFF.
This also ensures cutting-of the auxillary feedback voltage, restoring the entire primary section to its original switched OFF state.
The cycle now begins afresh and is switched continuously at around 60kHz rate which may be varied by increasing or decreasing the values of the 2n2 feed back capacitor and the 100pF base capacitor of BC546 NPN (it's not recommended though).
During the switched OFF periods of the primary winding, an induced equivalent back emf is transferred to the secondary winding which translates it into the specified stepped down low voltage, high current secondary output.
The above secondary output is appropriately rectified and filtered by the high current diode and a filter capacitor.
A feedback stage across the secondary and the primary stages is implemented via a optocoupler which determines the required fixed, regulated output voltage.
The zener associated with the optocoupler may be tweaked for getting different stabilized outputs for the desired applications.
Here it has been fixed to about 14.4V which becomes the optimal level for charging a 12V lead acid battery.
The current output of this transformerless 12V, 5 amp smps battery charger can also be changed by two methods.
Either by modifying the secondary wire thickness of the transformer or by tweaking the value of the 0.22 ohm resistor positioned across the source/ground terminals of the mosfet.
The input stage typically consists of a bridge rectifier stage, followed by an NTC and filter stage.
The input EMI coil is optional.
Circuit Diagram
How to Wind the ferrite transformer
The ferrite transformer is wound over a 15mm EE ferrite core compatible plastic bobbin.
The one half primary is wound first, using a 0.4mm super enamelled copper wire (15 turns).
Secure the end of this on one of the primary side pins of the bobbin. Cover the winding with a layer of insulation tape.
Next wind the secondary winding (5 turns) using 0.6mm wire over it.
Terminate the ends on the secondary pins of the bobbin.
Apply insulation tape over this winding.
On this wind 3 turns of 0.4mm auxiliary winding, cover it with insulation tape.
Finally continue from the secured end of the first primary winding and wind 15 more turns over the above auxiliary wind to finish of the ferrite transformer coils.
Put a few layers of insulation tape to finalize the winding insulation.
Fix the EE cores and tape it yet again along its periphery.
Make sure the EE core edges are separated with an air gap through a piece of insulation tape or a paper, this will prevent core saturation and stalling of the desired smps induction.
THE CIRCUIT EXPLAINED ABOVE IS NOT ISOLATED FROM MAINS, AND THEREFORE IS EXTREMELY DANGEROUS TO TOUCH WHILE EXPERIMENTING IN POWERED CONDITION, AND ALSO THE DESIGN IS RECOMMENDED SPECIFICALLY FOR USERS HAVING ADVANCED KNOWLEDGE IN THE FIELD, NOT FOR THE NEWBIES..
charan says
hello swagatam, ive two questions
1-Can i use mct2e optocoupler instead of 4n35 & also replace ba159 by fr107 ?
2-I cant find .4mm wire from store so can i use those taken from cfl transformer which is generally available ?
Swag says
Hi Charan,
1) You can use MCT2E, and FR107
2).4mm is not critical you can try any nearby value
Shigida says
Good morning Sir!
This time ,I want to try to make this Battery charger.As I look to the diagram,
there is no value for the EMI PFC coil.Pls can you give me some hint how to difine the value and/or how to make it?
Swag says
Shigida, the coil is not too critical for home use.
you can use 20 turns of 0.5mm magnet wire on each side over a ferrite torroidal ring.
barrah gi says
i ve 3524 inverter if i apply feedback frm output secondary there is problem but without feedback no problems feedback is applied to pin1of 3524.what can i do
Swag says
what kind of problem are you facing??
Thoombro says
Sir i have 12v 1amp powersupply led driver. Can i convert it into 14v 10 amp powersupply just by replacing the transformer with thicker wire and adding more winding and replacing the transistor with more powerful one.
Thanks for the quick reply on other threads
Swag says
you can do it, but make sure to do it from both the sides primary and secondary with proper calculations
Thoombro says
Can i use bigger ferrite transformer instead of the stock one in the circuit
Swag says
the ferrite core must accommodate the winding perfectly, it should not be big and loose or too crammed…
Joel says
Mr. Swagatam, I am looking for a circuit that will take an input of 50v down to 12v with an output of 12v. Max current output around 5amps. The input voltage should be an automatic sense. Any help will be greatly and thankfully accepted. Thanks much, Joel
Swag says
Joel, you can try any DC to DC buck converter such as this:
https://homemade-circuits.com/5v-pwm-solar-battery-charger-circuit/
Joel says
I am not sure if I gave you all the information. what I am trying to do is be able to connect to say a forklift (24 to 48 volts) and get the 12th out I need, the issue is that I want to connect to any voltage between the 48 to 12 volt range and the circuit be able to take that and give me the 12v I need, without any manual changes from me.
Swag says
You mean you want to have a constant 12V output from any voltage source between 12V and 48V? Is that right?
Did you consider using a linear voltage regulators, and what’ll be the required current output from the 12V?
Joel says
correct on the output voltage, the current output needs to be 5 amps. I have thought about linear regs but, most have a 40 v max input.
Swag says
You can try the following concept, ignore the current control section if you don’t wish to use it.
https://homemade-circuits.com/universal-variable-power-supply-circuit/
Ajitkumar says
Sir
I need a 38 volt 9 amp Lead Acid automatic battery charger circuit for Three 12 volt battery charging in series.
Do you have any suitable circuit diagram ? Please help.
regards
Ajitkumar
Swag says
Ajit, you can try the circuits presented in the following article:
https://homemade-circuits.com/make-this-48v-automatic-battery-charger/
Mr Stewart Aspen says
Hello Mr Swagatam, I have built the power supply as you have detailed. It will work at low (30V) but self destructs at mains (240Vac). Has the circuit been designed for 110V or 240V?
I have found similar circuits, but they use a far larger number of turns on the primary winding. I am also concerned that the 0R22 resistor is too low a value to initiate oscillation.
Any advice you can provide would be most useful.
Regards Stewart.
Swag says
Hello Stewart, This design is for 220V operation and is thoroughly and successfully tested by many of the blog readers.
khurram farooq says
Hello dear sir,
i need help sir can you explain this cct diagram with the help of block diagram on this schematic like driver section, oscillator section etc….
Best Regards:
Farooq
Swag says
Hello Farooq, the stages can be easily visualized by looking at the diagram, there is bridge rectifier stage, after that there is a mosfet stage which acts like a driver stage as well as an oscillator stage. The BC547 stage forms the current control stage while the opto coupler forms the feedback control stage for stabilizing the output
pavan says
Hai sir ,
I need 60v/3amps charger circuit for battery charging . and it should be cv and cc .pls suggest me the circuit .
Swag says
Hi Pavan, you can try the following design
https://homemade-circuits.com/how-to-make-versatile-variable-voltage/
pavan says
Thanks for your replay .sir actually i want to design 60v /3amps charger circuit in flyback topology . i need perfect design . pls help me
Swag says
Pavan, you can try and modify the following concept
https://homemade-circuits.com/smps-2-x-50v-350w-circuit-for-audio/
Sheraz says
Dear sir! i am using pesim software for designing smps transformer but i dont understand about the wire guage let say AWG25.5 x 3, understand AWG25.5 but for what the x 3?
Swag says
x 3 could mean 3 wires held together and wound together in a bifilar mode. 3 wire strands wind up simultaneously instead of one single thicker wire, this helps in getting better skin depth, higher amp efficiency, and compact winding
Saikat Jana says
TRANSFORMER SPECIFICATION FOR 12V 5Amp OUTPUT AND PLEASE HELP ME WITH SOME EXPLANATION ABOUT THE TRANSFORMER
Swag says
the winding procedure is already explained in the article
Saikat Jana says
is it tested for 12Volt 5Amps o/p
Swag says
yes it is fully tested!
Saikat Jana says
CAN I USE THIS CIRCUIT AS 12V 5AMP SMPS POWER SUPPLY
Swag says
yes you can, for more options you can check out this link
https://homemade-circuits.com/?s=smps
Saikat Jana says
sir please send me the transformer coil inductance
Swag says
inductance is not there with me, but the winding details is given in the article and should be enough for the construction.
Sisoncs Simon says
sir,
please publish pinout of 4N35 optocoupler to the board,there is no indication please update on circuit immediately.
Swag says
you can check it from the datasheet of the IC, or from Google images, it’s just a matter of a minute.
Sisin says
Ok sir but the anode and cathode of optocoupler connect to which part of the circuit please explain….
Swag says
anode can be seen connected to zener diode, and cathode to (-) line
Sisin says
Thank u sir for your immediate response..bcz of white background cant notice.
Swag says
you are welcome!!
Zakie says
Hi sir, i made this circuit but it’s didn’t work
The output voltage is 0v
I used 1n4007(standard recovery rectifier) instead of ba159
And 817 optocoupler
I replace 10uf 400v with 100uf 400v
And i remove NTC and EMI
Can you help me to solve this problem?
Thanks
Swag says
Hi Zakie, It can be difficult to troubleshoot the fault because I cannot check what may be the problem in your circuit…the ferrite transformer is the crucial thing in the design, if it is not wound correctly then the circuit will simply not respond or even burn into flames…so check the transformer once again and also the other connections. the circuit should first oscillate to produce any form of result, so check whether your primary side is oscillating at a frequency higher than 20kHz or 40kHz
Zakie says
But can i replace ba159 with 1n4007(standard recovery)?
and what is mean of dot(.) in your schematic sir?
Swag says
for testing purpose you can do it, but for the final use it must be replaced with a fast recovery diode…
Zakie says
And can i use 0.25mm wire for all winding?
Thanks sir
Swag says
for experimenting you can try it…it should work with some unknown current output.
always connect a 100 watt bulb in series with the input AC supply, in case if something goes wrong….
Mohiuddin Armaan says
Dear sir ,
please describe the Ferrite transformer turns calculation with example and auxiliary winding.
Swag says
Armaan, the details are already given in the article, you have to do exactly as per the given specifications
olupot says
thanks for your quick reply i was a little worried have a gud day sir
Swag says
you are welcome Olupot!
olupot says
hello sir i have a question can i use a 4pin optocoupler when i do not have a 6pin optocoupler with me thanks
Swag says
Hi Olupot, yes you can use it….no problem
Unknown says
if i use bigger VA core can increase power?
Swagatam says
yes, I think that's possible, the 0.22 ohm will also need to be modified
OLUPOT DANIEL says
hello sir nice day and thanks for the great job you do i appreciate. now sir i needed a simple personal multi output charger but using the same circuit. i want it at 5v 2amp,9v 2amps, 12v 5amps, 20v 3amps wat can i modify to get all those out puts thanks alot
Swagatam says
Thanks Olupot,
You can try modifying the opto resistor and the secondary winding to get those outputs, or simply you can modify the optocoupler section with a pot to make the output variable, as explained below:
https://homemade-circuits.com/2015/04/how-to-make-variable-smps-driver-circuit.html
s3nsit says
Sir hi again.We have discussed on comment section of your other smps homemade circuits. I want to ask you some questions to define some issues.
First you mentione a 15mm EE compatible bobbin on the end. Is this an EE15 core? Cause i think that with a frequency of 60kHz the minimum ferrite core that can provide 60watt (assuming flyback topology-PC40 ferrite material-minimum air gap possible) is EE25.
I will test your circuit using EE25 (salvaged from a HP inkjet supply) on 60 and 120 khz and keep you posted about the results.
Nice simple and very educational self oscillating flyback operation explanation. If you try understand the same oscillating operation from the variou pdfs around the internet…good luck! Thank you!
Swagatam says
Thank you S3nsit,
the rule of the thumb is to use a ferrite core/bobbin that accommodates the specified winding data with minimum gaps, that is in the most optimal way, making sure that the winding is done using a winding machine not by hand.
here we cannot use formulas or calculations for the transformer because the design has been thoroughly tested, and if everything is done exactly as per the given data the circuit has to work without fail… and moreover the winding details are not extremely critical, a little discrepancy will not cause any harm to the final output…
s3nsit says
Ok in understand. By the way i think that most people complaining about mosfet overheating they used their EE cores as they came from factory. Ungapped. Zero gap as you mentione causes saturation, fall of inductance so the transformer primary coil becomes a short circuit thats why mosfets overheats.
If people are reading this in order to add air gap, take on of the two EE halves and trim its center leg with no600 sand paper. Taking care not to damage the outer legs of EE half.
Swagatam says
OK thanks for the updating the info, however I think inserting a paper between the outer arms of the E cores can be an easier option….
Gustavo Vera says
Hi Sir. I want to salvage some components from an old ATX PC power supply so could this design be adapted to use a transformer with 20 + 20 turns primary winding?
Swagatam says
Hi Gustava, No, the above smps circuit cannot be used with any other transformer except the one which has been specified in the article…
Olybest says
Sir, i want to build a smps of television set using already existing transformer but i want to use uc3842n and 8n60 and i don't want to use optocoupler, please help me. I want variable volts of 110v – 135v. Please help me. I can't easily want transistor driver instead of ic but with no opto.
Swagatam says
OLybest, It may be possible only after doing proper calculations and modifications, you cannot simply connect a available transformer with another SMPS circuit, that can cause malfunctioninh or even a fire…an example article can be seen here, please check out how all the calculations are implemented for achieving a precise and safe functioning of the circuit
https://homemade-circuits.com/2017/06/12v-2-amp-smps-circuit.html
Rajan Mayekar says
Dear Sir
Can you send me 12 volt 5 amp power supply i am in mumbai My address is PROX SYNERGY , b16,bharat market,subhash nagar,asalpha, ghatkopar west
mumbai, 400084 and please tel me how to pay what is amount
Swagatam says
Dear Rajan, if you are located in Ghatkopar then visiting Lamington road shouldn't be difficult for you?…you can go to Lamington road and get the desired SMPS of your choice from there at the most reasonable cost…
dubba says
Hi Swagatam Majumdar,
Very good DIY instructions, What will it cost in INR? I am very lazy at the moment, can you quote for 9V 5 Amp with casing and deliver to Rourkela, Odisha? Vijay
Swagatam says
Thank you Dubba, the final cost including shipping will be around 600/-INR…the actual cost could be anywhere near 300/- INR
dubba says
Do you mean both 12V5A psu and 9V5A costs the same? But you didn't mention that you can ship one 9V5A converter to my address, via courier? I am actually in need of one of 9v5A and 12v5A each ASAP & and can't afford to divert attn. (lazy) in scrounge parts for DIY of above.
Swagatam says
12V will be costlier….however sorry I may not be able to send it due to my busy schedule, initially I thought that I should start selling items in my site but for the moment I have decided not to go ahead with it due to lack of time…
Ayush Sharma says
Hello
Thanks for posting nice SMPS circuit!
I have a small query
0.4mm is used for primary and auxiliary winding
and 0.7mm copper is used for secondary winding
is there will be any problem if we will use all windings with 0.7mm?
Swagatam says
No problem, you can use 0.7mm for all winding
AJAY K.V says
Sir,
could you please tell me what exactly is the function of EMI PFC coil.
If my input is 230V,30A what value of PFC coil should i use?
Swagatam says
Ajay, PFC coil cancels the reverse EMFs and spikes generated by the inductors inside electronic circuits and prevents these unwanted disturbances from being injected into the mains wiring and other sensitive appliances.
you can read more about it here
https://homemade-circuits.com/2016/03/power-factor-correction-pfc-circuit.html
AJAY K.V says
Sir,
How should i change the circuit to get an output of 110V and 60A
If the output is given to a battery of 100V and 96Ah could you suggest me some method to reduce the current(60A to 5/10 A) to the battery once 80%of the battery is reached.
Swagatam says
Ajay, I would advise you to first try the shown 5 amp basic design, if you succeed then you can try upgrading it for higher amps…
Vikram Sha says
Can i increase the diameter of the winding both in the primary and secondary to increase the power rating. I'm using 13nm60 mosfet will it do the trick.
Swagatam says
yes you can, but not by increasing the diameter of the winding, rather the diameter of the wire cross section….this can be alternatively done by using many thin strands of wires in parallel instead of using a single thick wire
I am not sure about this mosfet equivalent.
Rajan Mayekar says
Dear Sir Can you provide pcb layout
Swagatam says
sorry Rajan, due to lack of time a PCB may not be possible at the moment, but in future I may think about it.
Devendra Pal says
dear sir, we are making 12v 1 amp power supply from your circuits. It is giving us 12.5 V output but after few minutes all diodes in bridge , both ba159 and diodes 6a4 in output 18V zener and mosfet is blown(shorted). It happened 3 times same. Circuit is taking 0.2A at its input 230 V and we are applying load of 50ohm.
can tell us the reason why it is happennig
Swagatam says
Devendra, the transformer is quite critical here and will need to be correctly optimized, or else the devices will keep blowing of.
at 0.2A x 220V input the 12.5V would be accompanied with 44/12 = 3.6 amps
and with 50 ohms the output consumption would be
I = V/R = 12.5/50 = 0.25 amps which looks fine to me.
you should measure the output current also using a DMM while testing the unit with a 40 watt bulb at the input to prevent further blowing of the parts.
the output current reading will identify the actual reason of the issue.
nivas .newlook says
Sir i want 5V 7Amp smps with 3843IC. there is some problem in my design which is already mailed to you.
how to set hiccup mode in this? I error amplifier is disabled by grounding the pin 2.is it or some other problem?
Thanks in advance
Swagatam says
Nivas, it will be difficult for me to troubleshoot the deign because I have not yet studied about this IC and it might take quite some time for me to go through and understand the datasheets and specifications in detail
Владимир Ланин says
Hi Sir!
What should I do to change field effect transistor to bipolar? Is it possible?
Swagatam says
Владимир, you can try MJE13005, and replace its collector, emitter, base with the mosfets drain, source, gate respectively.
I guess no other changes would be required
shahzad hanif says
How can i change this to 12V/10A
Swagatam says
by modifying the ferrite transformer winding and the mosfet
arun vijayan says
Dear sir, Can I use this circuit as a 12V DC power supply with battery backup for my CCTV system.I have 4 CCTV cameras and one 4 channel DVR.
Arun Vijayan
Swagatam says
Dear Arjun, yes you can use the above SMPS for the mentioned required!
but only if the total requirement of all the units is within 4 amps
Muhammad Noman Aslam says
Hello Sir
Hope so you are doing well.
Sir i have made this circuit. At no load output is perfect. But problem is that when i applied a load the voltage goes to drop to 5,6 Volt. Please help me to overcome this problem
Best Regards
Muhammad Noman Aslam says
Hello Sir
Hope so you are doing well.
I have made this SMPS according to your circuit. Its giving exactly 12 Volt output without load. Problem is that when i apply a load voltage became decreasing. please help me how can i overcome this problem.
Thanks
Swagatam says
Hello Muhammad, the heart of the circuit is its transformer, it needs to be built correctly, if any of the standard rules are ignored then the transformer could behave inefficiently,so please make sure that you have built it as per the standard rules that apply to SMpS ferrite transformers, or may be you can take the help of a professional experienced ferrite trafo winder for getting a perfectly built transformer….
NISHANT RAJGARHIA says
can it be tested using variac transformer???what is the minimum working voltage?
Thanks in advance.
Swagatam says
yes it can tested with a variac..minimum operating voltage is 100V
Sanjeevkant Sharma says
Dear swagatam
Is it possible to make EMI Tr at home ? if yes than please give details.
Thanks
Swagatam says
Dear Sanjeev, I do not have the exact data, you can try 50 turns of 26SWG magnet wire for each side, over a ferrite ring core
サントスアラン says
Good evening Mr. Swagatam , greetings from Mexico , I am doing the switched 12V supply 5Amp , I have doubts as to the meaning of the windings , since I'm using a transformer ferrite core , and so far have had failures, burning fuses , diodes 1N4007 stop working and have come to bust a zener diode, the MOSFET is burned me , and continued doing the circuit, any recommendations? Thank you so much.
Alan Santos.
Swagatam says
Good evening Santos, the ferrite transformer is the heart of the circuit, everything depends on its correctness…the transformer must not saturate while operating, and this could happen due to wrong winding configuration or if the two E-core touching surfaces are not separated with a paper or plastic.
so make sure the transformer is correctly wound as per the given data or better take the help of a professional winder.
IRIE BEADS says
Instead of the 4n35 what else can i use? The voltage i want is 35volts.What type of transistor is connected to the 1k ? Instead of the irf840 im planing on using irf640. Its going to be connect to 110 a.c
Swagatam says
you can use SAT400 or any similar opto.
IRF640 will do for 110V supply input
1K is connected BC547…please click the diagram to enlarge
IRIE BEADS says
Ok,so how can i get the 35volts?
Ezequiel says
Hi, Sir. Since there are several ferrite cores, I'll appreciate more info about the ferrite core. Like the measures. Thanks! Excellent job.
Swagatam says
Hi Ezequiel, thanks, the best way to select the E core is to find the one which accommodates the winding most optimally, a qualified winder will be able to suggest correctly by referring to the number of turns data
aamin007 says
D.Sir, kindly tell me how to make an adapter that( shuld be 13.5 volts with 5 amp) from smps? I need this adapter Creative 5 in 1 speaker, as i've lost the original adapter.
Swagatam says
Aamin, you can try the above shown circuit, the output zener diode can be appropriately modified for acquiring the intended 13.5V
However do it only if you have a thorough knowledge regarding SMPS circuits and how they work
Swagatam says
AA, you can refer to the following article for more info
https://homemade-circuits.com/2015/04/how-to-make-variable-smps-driver-circuit.html
Anonymous says
Dear sir…..heating of IRF840 is there. I have gone through all the blogs above and made the circuit strictly as per given outlay. The dc instant current can go upto 3amps. How IN4007 can handle this current? Circuit works safely for 1 amp output only by puting s resister as 1 ohm to keep current at .6 amp. Even at this current mosfet is getting heated up and destroying. Have yu tested this circuit personaly? Can yu post a photograph of working model.
Swagatam says
yes it was tested successfully by one of my friends a long time ago, the mosfet will heat up only when the transformer has some problems. You must get it checked from an expert who knows all about switching circuits.
The 3amp should be at the secondary side not at the primary side, the primary side should not consume more than 0.3 to 0.5 amps…if it's exceeding this value then your transformer could be malfunctioning.
Anonymous says
Hi,
good articles.
But I confused about the title, …"transformerless …. ", while there are a transformer.
As well, it said "not isolated from mains", while the secondary circuit is clearlya isolated from the primary circuit, since no direct galvanic connection between primary circuit – secondary circuit. Transfomer is magnetic coupling, and the feedback link is optocoupled. So the title "transformerless" and "not isolated from main" does not correct.
rgds
Swagatam says
Hi, thanks….here "transformer-less" refers to the elimination of the big bulky iron core transformer, and the "compact feature"….and "not isolated from mains" refers to the circuit as a whole, which is dangerous to touch while experimenting in an unenclosed condition and switched ON
Abobaker Atef says
Sir, wouldn't the mosfet fail against the emf generated at switching off .. I mean we're switching off ~ 5 Amps of the primary in a snupper of 10nf and 18kohm that will create almost 4kv at the drain !!
Swagatam says
Hi Abobaker, the reverse EMF would pass through the diode and the 10nF, the mosfet will have no connection with this cycle
by the way how can it be 4kV ???
Abobaker Atef says
if say the primary winding had 3 Amps peak current, when the MOSFET is switched off all 3 Amp would continue to flow through the diode into the 10nF so it'll be charged according to I=C*(delta V/delta t) for an average I of 1.5 Amps during the switch off time, so (I/C)*delta t = (1.5/10n)*(0.5/60k) = delta V = 1.25kV … this is for single cycle, but for steady state operation this will rise even more until the 18kohm can dissipate average current of 0.75 Amp during the full cycle time (delta t = 1/60000) this'll yield a huge number for steady state even more than 4kV => 0.75*18k … the 4kV i came up with it from the results of a simulation (not very accurate of course nor are my calculations but they both exceed the 500V by a far value) … I like your circuit very much and thank you for sharing it, I'm just trying to make sure it's safe before i plug that in my mains outlet
Swagatam says
Thanks Abubaker, This is not my design, and sorry I am unable to verify your calculations due to lack of time, but sorry I think interpretation may not be correct….the voltage and current in an inductor solely depends on the inductance (number of turns) and the switching duty cycle, both these parameters in this circuit are adjusted in such a way that the current can never exceed a few 100 mA, and the voltage can never reach to kV…the secondary can have higher amps but the primary will be able deliver just a few 100mA because of the high frequency switching which could be well over 100 or 150kHz
Swagatam says
although this circuit is not mine, it is a well tested circuit, so if you do everything correctly there's little chance of things going in smokes…preferably connect a 200 watt bulb in series with the input to avoid a possible blown fuse etc..
Aghos says
Hello Sir,
In the winding procedure,Why didn't you coil the 2x 15 as 30 turns first, then proceeding to the 3 turns beneath, before adding the secondary 5turns, or is there a laid down rule? Thanks in advance
Swagatam says
Hello Aghos, there are no laid down rules as such….but doing the way it's explained in the article will help to produce a better response from the winding due to their layered kind of nature
Ainsworth Lynch says
check this link
https://www.dropbox.com/s/1jv5ohla9jwc4xq/dual-polarity-power-supply.jpg?dl=0
I dont know if your aware of this method of making a dual polarity power supply I need to make an amplifier circuit but my transformer isnt center tapped I was wondering if this method would be ok it looks ok to me.
If its ok say I wanted 1500 watts from this would how would I arrange this they dont really stock high wattage zener diodes in my country would I need higher wattage zener and would I need to change or add anthing else for powering an amplifier
Swagatam says
this will work for low current applications, for a 1500 watt load the zeners will need to be 1500 watt each….not a feasible idea
Avinashsingh Chauhan says
hello sir,
in the above ckt is mosfet based regultor/ic is suitable for nonstop continous operation ? what precuations should be taken care if using for continous nonstop usage. Secondly i have seen some smps design using pulse transformer.. Can u explain me th role and functionality of pulse transformer in the smps..?
thanks
Swagatam says
Hello Avinash, I would recommend you to check the waveform of this circuit, so that you can confirm how much the current may be dropping in the continuous mode, and then alter the output capacitor accordingly.
This is not my design so I cannot confirm the waveform just by looking the configuration.
to learn more you can refer PAGE 5 from this pdf article:
ww1.microchip.com/downloads/en/AppNotes/01207B.pdf
you can also refer to page 7 for the design considerations and PRECAUTIONS while selecting the components.
Pulse transformers are mainly used for providing galvanic isolation to the primary SMPS stage and for ensuring a safer operating environment to the vulnerable electronics from the high mains input…. quite like an optocoupler
rutvij patel says
thank you for your reply sir
one another quistion is that i can make this ckt as smps not as battery charger.
Please also give me ckt diafram for 12v 2amp.
Swagatam says
It is an SMPS design, and it will work for 12V 2 amp applications also.
MOHD SHAHID says
sir
i wanna make this circuit using viper-27 what would be the reading of the capacitors for this.
Swagatam says
Mohmd, is the Viper27 rated at 5amps?
rutvij patel says
Dear Sir,
Can i use this smps for camera supply 24*7 days
Swagatam says
Dear Rutvi, yes you can use it only if the camera volts specs matches the circuit's output volt specs.
style says
Sir,
I have an SMPS, who's NTC is blown and the problem is not mentioned any value in it ,how to find the value.
Swagatam says
style you can try a 5 ohm 11mm NTC
Raj says
DEAR SIR,
I WOULD LIKE TO DESIGN 48V, 12 AH CHARGER TO CHARGE THE 100 AH BATTERY. SO PLEASE SUGGEST ME WHAT WILL BE CIRCUIT OF IT.
Swagatam says
Dear Raj, you can refer to the following article and build any of the designs preferred by you from the article:
https://homemade-circuits.com/2014/04/48v-solar-battery-charger-circuit-with.html
Rahul Arya says
Dear sir, i have a 12v 5amp smps adopter but during charging a battery it is short circuit due to wrong polarity connected to battery…and i found that the IC is damage, the problem is that IC details is not given on it for replacing…plz help…
Swagatam says
Dear Rahul, That can be extremely difficult to judge, sorry I can't specify without practically seeing the entire schematic.
afam nzoiwu says
I have done this circuit severally. i got some and some failed. and the section of the failure is the mosfet. it damages the mosfet. what is the cause.
Swagatam says
afam, use a 100 watt bulb in series with the input while testing the circuit, and then you can troubleshoot the issue in a stepwise manner without damaging the mosfet.
sebi davis says
SIR , I WANT MAKE 12V /10A POWER SUPPLY FOR INDUCTION HEATING CIRCUIT,PRESENTLY I AM USE TRANCEFORMER IT TOO BULKY,MY AIM IS MOBILE INDUCTION HEATER (WEIGHT LESS) SO ONLY OPTION REDUCE SIZE OF THE TRANCEFORMER ,COULD YOU HELP ME?
Swagatam says
Sebi, you can try playing with the above explained design and see whether it works out for you or not?
Parag Karekar says
Hello Sir, How can I do calculations of transformer?
i.e. Number of turns, core size, core material and wire gauge
Swagatam says
Hello Parag, the details are given at the bottom section of the article.
zahidsre1288 says
hello sir i need mobile phone charger circuit diagram 220v ac to 6.0 dc volt transformer less.
Swagatam says
it's already posted in this blog, pls use the search box to find it.
Paras Thakkar says
sir what is the specification of BJT near ZD 16-18V .please reply
Swagatam says
it can be a BC547 transistor
Paras Thakkar says
sir what is T2.5A is that a fuse.
Swagatam says
yes it's a fuse
Hui-wijaya Wijaya says
when i need more current output about 10-20A, what should i need to change on the schematic? ???
Swagatam says
change the winding and use more parallel wires in it, and change the 0.22 ohm resistor at the mosfet source to 0.06 ohms
Hui-wijaya Wijaya says
hi Mr.. may i replaced the opto with pc817 since i dont have opto as specified on the schematic.. ? i have trafo ETD53 .. it can be used in this smps ??
Swagatam says
yes pc817 will do.
the trafo winding specs must match the indicated data, otherwise it won't work
ashwani mishra says
SIR,
WHAT DOES 6A4* 2 NOS. IN PARALLEL MEAN AND
T2,5 A MEAN AND
WHAT IS THE SPECIFICATION OF TH-NTC
0R22, AND DOES 22R MEAN 220 OHM
Swagatam says
ashwani, 6A4 is a 6amp diode, use two of these in parallel at the shown position….use SMD diodes and solder them such that these are pressed in contact one above the other.
ashwani mishra says
sir, can i use this circuit for charging car battery
Raymond Michael says
hello sir!
i need to produce the output of 30-0-30 (with a center tape) how can I achieve that, and how am I suppose to configure the coppler and the zener diode.
and lastly, can I use a power transistor insteady of a mosfet?
thanks in advance, be well sir.
Swagatam says
Hello Raymond, you can wind the secondary with 24 number of turns with a center tap at the 12th winding, and change the output zener with a 60V zener.
I am not sure whether the mosfet can be replaced with a BJT or not
Swagatam says
…the 22 ohm resistor will also need to be replaced with a 10k resistor.
Javad Farokhi says
Hello.
I have a map of the switching power supply 10 amps and 20 amps and 30 amps at a voltage of 12 V need. Dear Manager site map I have at my disposal. Thanks
email me:
captain.electronic@gmail.com
Swagatam says
OK you can send it to my emal ID
Fajar Sidik Priatna says
sir, how can i reduce current to 3 amps ??
and how i can increase voltage to 36 volts and make a range 30-36volts??
thx
Swagatam says
Fajar, you may have to increase the secondary turns from 5 to 12, and increase the associated zener diode value to 36V
for reducing current you may try using thinner wire for the secondary winding, although this may be an irrelevant parameter, you could use the same circuit for any purpose, just make sure that the load voltage spec is not lower than 34V
Fajar Sidik Priatna says
thx sir, i want to ask another question..
1. is it right the equation for your primer winding Np=(Vin*10^8) / (4*f*Bmax*Ac) with, Vin=310, f=60kHz, Bmax=1500, and Ac=1,5 ??
Fajar Sidik Priatna says
sir i want to ask another one,
1. is the base from opto 4n35 not use?? from your schema the base was not use..
Swagatam says
I have not studied about this formula yet, so I cannot say much about it, I will do some research and then I might comment.
Swagatam says
4n35 has only four legs, so the base is not applicable in the device…..
Fajar Sidik Priatna says
thx sir, sir i want to ask again, what the function from NTC thermistor?
and should i use 10k NTC?
Swagatam says
It's for suppressing the initial high current inrush by providing an increased momentary resistance.
You can use the one which is shown in the following article:
https://homemade-circuits.com/2013/02/using-ntc-resistor-as-surge-suppressor.html
leonardo cuello says
Hi, I'm building this power supply for 12V 20A and I find the problem that in my city there are no copper wire diameters requested. I got a few meters in diameter 0.6mm and 1.16mm for the primary and the secondary. it operates the same way? can i use a toroidal core? Greetings!
Swagatam says
Hi. I am not sure about the results with these wires but there's no harm in trying it, you can use a fuse in series or a 200 watt bulb to make sure nothing burns if anything goes wrong….yes torroidal ferrite ring will do as the transformer
leonardo cuello says
Hi, thanks for your reply! I'll try with these diameters and I will comment the results.
regards
Swagatam says
OK, great, thanks!
Naufan says
Sir, i decided to make this circuit produce 24V 10A at the output. It mean that i must change the value of the zener diode to the optocoupler… What value should i change for the zener diode?
Swagatam says
yes, the zener diode can be changed to a 30V zener for increasing the voltage, and also use more number of wires in parallel for winding the secondary of the transformer for enabling 10amp output
Naufan says
Sir, instead of using EE Core. Can i use Toroidal Core?
Can i replace the BA 159 With 2X 1N4148 In Series?
Swagatam says
It will work if you are able to accommodate all the winding correctly and comfortably over the toroidal core
you can try 1n4148 in place of ba159
Naufan says
Yes, but sir, can 1N4148 diode handle up to 1KV of Voltage and 2A of Current?
Swagatam says
1n4148 won't work it seems, you can try any other adequately rated fast recovery rectifier diode.
Kausik Dana says
Thanks Swagatam for creating the site and maintaining this blog. I am an electronics enthusiast from my school days. I need a solution from you regarding 48v 18AH lead acid batttery charger for my battery bike. Two of my early smps based chargers broke down and nobody even agreed to repair it. Please suggest me a circuit which I can make for charging the 48v 18AH batteries.Thanks in advance.
Swagatam says
Thanks Kausik, I would recommend a transformer based circuit for charging your battery, because SMPS can be costly and not customizable as per ones requirements.
so you can buy a 25-0-25V transformer, rectify the output using bridge and and filter caps…and use the following circuit to regulate the voltage to the specified levels for charging charging your 48V battery:
https://homemade-circuits.com/2012/01/how-to-make-versatile-variable-voltage.html
Swagatam says
…you'll need a 25-0-25V trafo with 3 amp current capacity
Kausik Dana says
Many thanks Swagatam. I will make one.
Swagatam says
you are welcome
Raymond Michael says
hello Swagatam, I went to the shop today , I had a very bad day!!! I got everything as required in the circuit except for 3 components ; IRF840 , BA159 and 2n2/100v,
I have everything done here except for those items, what can I do is there an replacement I can look for????
Thanks a lot for your help
Swagatam says
hello Raymond,
for the mosfet you can try any 700V/5amp mosfet….2n2 can be replaced with any nearby value, such as 3.3nF, or two 1nF in parallel etc.
BA159 can also be replaced with any 1amp/300V fast recovery diode…
Raymond Michael says
Thanks for the help sir!
I have a stupid idea here, I want to produce dual 130ac ( 130 – 0 – 130) from the magic transformerless circuit of yours, what am I suppose to do to make it, the current can be 30A or even higher.
I am waiting for your reply sir.
My regards to U.
""Life is too short, cherish the you have by doing what you love and enjoy the most, provided NOBODY GETS HURT""
Jamal Behzadi Hajat Aghaie says
Hi Swagatam
Thanks for sharing this circuit
I have one question
Does the mosfet even get warm and does it need a heatsink at all?
Swagatam says
You are welcome Micheal!
I think the following design can be tried for your requirement, the winding parameters can be easily modified for getting the specified current/voltage as per the data
https://homemade-circuits.com/2014/06/smps-2-x-50v-350w-circuit-for-audio.html
Swagatam says
Hi Jamal,
yes, the mosfet could get significantly warm! A heatsink would be recommended
psa says
Can i keep auxillary winding 3 turns 0.4mm wire as it is (or)
Can i change turns and parallel wires with respect to primary & secondary
What is the use of auxillary winding?
Swagatam says
auxiliary winding needs to be kept fixed as per the shown data regardless of any change on the other winding…it's only for triggering for the mosfet and for sustaining the osciilations
psa says
can i tweak transformer's secondary side turns and parallel wires to get 60volt 50amps as output from this circuit
Swagatam says
60V is possible but 50 amps is extremely high, I am not sure about it.
psa says
thanks for ur kind response
i want to design a 70volt 15amps dc output smps (by refering to ur design)
can i connect three sets of above mentioned smps rating in parallel to get a
70volt 45amps output
Swagatam says
yes, according to me that's definitely possible.
psa says
For making 70v 15a smps
Planned -> 310vdc 8a at input (after rectification)
Doubt -> Can i change any rating of these devices.
(470k 1W,2n2,1k,18k 1W,10n 500v)
Planned ->Just put POT in output side for adjusting voltage instead of zener &
use 4N35 as it is.
Doubt ->Can i use 4n35 for this proposal
Final doubt
In ur design 2.5A for 1Adc input
for 8Adc input which AC rated fuse can i use
Swagatam says
for upgrading amp at the input you'll need to make sure that only the mosfet is rated accordingly, other components might not any change. the trafo wire might also need an upgrade, more parallel strands should be tried over the existing winding.
in order to make the SMPS variable, you can try the instructions provided in the following article:
https://homemade-circuits.com/2015/04/how-to-make-variable-smps-driver-circuit.html
any 4 pin opto can be used, that's not critical.
for 8amp current you must use an 8amp to 10amp fuse.
Amrut Ubare says
Thanks in advance, I would like to know about design of ferrite core transformer (ferrite core size), please help me sir.
Swagatam says
thanks…it's 15mm, the details are furnished in the article.
Supun Fernando says
Thanks for this circuit. it works really well and thanks for your advices..
Swagatam says
you are most welcome!
Supun Fernando says
is there a replacement cap for 2.2n 100v? plz help sir..
Swagatam says
use two 1nF/100V in parallel
Supun Fernando says
what is meant by 6A4 * 2 diodes in parallel ? do i need to make a bridge or can i use a single diode? please help sir….
Swagatam says
you can use a single 10amp diode, preferably it should be a Schottky diode
Supun Fernando says
what is meant by 6A4*2 diodes? do i need to make diode bridge or can i use single diode?please help sir….
Swagatam says
those are 6 amp rectifier diodes
adam ubaid says
choper ferrte calculations kya hain??????????////
Swagatam says
the details are given at the bottom section of the article
adam ubaid says
transformer calculations plz
btaein
adam ubaid says
plz
choper ki calculation kese hain???????????????
bataein plzzzzzzzzzzzzz
Raymond Michael says
Hi Swagatam!
I have viewed your articles about smps, and i am so proud to find your site;
the reason I was so fascinated by your designs is because I want to build a simple inverter which can give 300Watts to power my ceiling fan, small radio, light and charging phone.
I have tried one and it produces 203ACV from 12dcv supply just by increasing the secondary turns, I only tested it to power two 100W filament bulbs (not too bright) and two 18Watts energy server light. and it was working great without heating plus its not heavy at all !!!!
But some thing come up, that those smps are operated by using high frequency, how can I get 220ACV 50-60Hz?
Thanks again, and I am only waiting for you to inbox or if it happen you make an article about that please notiffy me.
thanks again
Swagatam says
Thanks Raymond, appreciate your response!
I have one example ferrite core inverter design in my blog which comprehensively explains the method of converting the high frequency stepped up voltage into 50Hz output, you can learn it here:
https://homemade-circuits.com/2014/07/5kva-ferrite-core-inverter-circuit.html
here's another design explaining a similar concept:
https://homemade-circuits.com/2015/05/smps-mains-voltage-stabilizer-circuit.html
TonyBen says
Hello Swagatam, i need you to explain why the primary winding turns is as low as 15T.
i understand the formula N= V * 10^8 / 4 * f * B * A is normally use to determine ferrite core winding. Is the this applicable here too? Because i use the specification of ETD39 to calculate the primary winding as per the circuit above. i got a primary turn of 103 @ 40kz.
But you recommended 30 turn be use for primary. Am i getting something wrong with my calculation? Also i though the turn ratio of the transformer is always close to the vin/vout ratio. looking at the circuit we are converting mains voltage(310dc) down to 12vdc. the voltage ratio in this case is not close to the turn ratio of 30/5. please can you educate me on this?
Swagatam says
Hello TonyBen,
The above circuit was not designed by me. Your assumption appears to be valid, however the relatively lower of number of turns in the design could be to allow higher current because as we all know that as the number of turns in a winding increases its ability to pass current decreases, so that could be one good reason of using lower number of turns.
Another factor could be the use of higher frequencies, because higher frequencies will allow lower number of turns to be used, and vice versa.
I would suggest you to go ahead according to your suggested formula results, and in order to increase current you can use many number of parallel strands for the primary winding, let's see how it performs
Nirvikal Lal says
I have a smps from a vcr which gives 5v and 12v but I don't know the ampere . I connected the 330v dc output to the smps wrongly suddenly my switching transistor blasted . Since the vcr was made in 1995 now I couldn't get that transistor. The transistor was TOP201Y and I checked for an equivalent that was TOP223Y but all were discontinued so I couldn't get it in any shops but data sheet says it's a 50w switching transistor so can u suggest me any switching transistor for this purpose
Swagatam says
It's not a transistor actually, it's an IC, and I am afraid there's no direct replacement for this switching feedback IC. There's one alternative in the form of TNY tiny switch but the configuration for this IC is different to the TOP IC in terms of their connections with the opto coupler…so it won't be of any good either.
Rentanu says
This circuit have under test before? i will try it for my project, thank you sir
Regard
Swagatam says
yes it is a tested design, but it is not recommended for the newcomers
Spoorti Doddamani says
Hello Sir, Could you help me design a power supply circuit with output voltage varying from 3V to -3V and current varying from 2A to -2A?
Thank you
Swagatam says
Hello spoorti, presently i do not have this circuit with me, if I get it will surely publish it for your reference.
anutosh didwaniya says
hello sir , i want to make a 8v,500ma & 5v ,300ma power supply in a 8051 ckt, in my opinion for this i should use double winding in secondary & reduce the thickness in secondary winding & change the zener.
sir plz guide me
Swagatam says
hello anutosh, you can at the most reduce the secondary wire gauge suitably, and change the zener to 8V or 5V that's all, no other changes would be required
anutosh didwaniya says
hello sir, in my previous question i want to make both o/p in single supply ,for it in can i use double winding togather & apply zener on 5 v supply only
Swagatam says
ashutosh, you don't have to put two winding, simply calculate it for 8V out and then add a 7805 IC with the output, so from the same winding you can achieve 8V and 5v together
Jideofor Igwe says
Irf840 mosfet cannot be used in flyback like u sugested, it has vds=500v(max), a flyback mosfet must be rated @ 2 x bus voltage + marging. that is 2 x 311v = 622v. Dat means a 700v mosfet and above is going to be used.
Muhammad Munir says
Dear tell me the complete action of circuit. why u did not used any pwm controller like uc3842,sg3525,tl494.
xavier Pereira says
Hello Swagatam
Some of your readers may not have understood that the little dots indicate polarity of the windings on the transformer. Get them wrong and you have a fried Mosfet! BY 199 and UF5404 can be used to replace the BA157
Swagatam says
Hello Xavier, thanks for your concern, but it may not be so critical…one has to simply follow the connection pattern of the winding exactly as given in the diagram for the primary,,,,if the lower auxiliary winding is connected wrongly by mistake would not do any harm to the devices, the system will not function that's the only thing that may possibly happen…but no mosfet will burn or get damaged.
The secondary is irrelevant, since it has only a single start to end winding.
xavier Pereira says
Hello Swagatam
Secondary polarity does make a difference, in my experience. If you scope the secondary AC output, you will see that it is asymmetric (eg more negative-going than positive). So if it is connected with wrong polarity, the SMPS has to work harder for the same output.
Swagatam says
Thanks Xavier, the diode and the capacitor polarity must be done according to the "dot" for the secondary, that's correct, but suppose if it's done the wrong way, in that case the output will simply show no voltage according to my simulation…because the output from secondary are ordinary rectangular waves, with positive peaks at the "dot" side of the winding.
Nitesh Agrawal says
Dear sir
ok
thanks
Nitesh Agrawal says
sir
Generally all 12v /5 amp smps consist min 47 mfd or 68mfd/400v as a input bulk capacitor .so in this ckt 10mfd/400v bulk capacitor for capable for handle full load?
i want to use this ckt as cctv smps.12v /5 amp
kindly inform me core grade, value & make I mean which AL value of core i used? & primary inductance also?
does 2 nos of 6A4 handle min 4.5 amp? Or any heating issue?if u run this smps constant up to long time min 12 hours?
Swagatam says
Nitesh, the AC input filtration is not so crucial, a 10uF is OK considering the fact that the output of the transformer has a much larger filter capacitor in the form of 2200uF capacitor
Swagatam says
the transformer can be built on any suitable EE core and bobbin, the winding details are provided in the article, I have no idea about the inductance values.
actually a high speed diode must be used in place of the 6A4 diodes, but you can go with the 6A4 diodes also, a single 6A4 will also work.
Nitesh Agrawal says
sir
ok
thanks
Nitesh Agrawal says
can i change output voltage from 11.5 to 14.5 v dc via preset.
if yes pl suggest me preset connection with preset value.
Swagatam says
use a 15V zener in place of the shown 13.5V zener
Nitesh Agrawal says
thanks sir
but i want to place preset for selection of voltage range from 11.5 to 14.5vdc?
kindly suggest me preset value with connection.May i connect 22 ohm preset in series with zener 15v?
Swagatam says
remove the zener and put a 1K preset there….connect its one lead to ground, one lead to 22 ohm and the center lead to the opto LED anode
Nitesh Agrawal says
Respected sir
i want to buy 02 complete ckt with preset.kindly help me , If u have ready then give me your contact detail & id.
Swagatam says
Dear Nitesh, I don't manufacture electronic circuits so I won't be able to provide to you, you can easily buy it from your local electronic market, these units have become very common nowadays.
style says
Hello Sir .
I will give all data whaterver I had to your email I'd within couple of days
Regards
Swagatam says
no problem style, take your own time and do it nicely 🙂
style says
Hello Sir
I have done only calcultion sir.still everything is in paper only.i dont know how to order raw material.Definitely I will give all detail … How to load complete detail can you tell me,actually its quite long,including gauge table and cross section table.or can I put directly into comment column?
Regards
Swagatam says
Thanks style, you can provide the data to my email ID which is given in the "contact" page below:
https://homemade-circuits.com/p/contact.html
style says
Hello sir,
You have any idea in transformer winding. I am assembling 55-0-55 with 12 amps.. I am doing E I lamination .I calculated all specification like No. Of turn,Gauge etc. I want to buy EI lamination stamping. Wat detail or specification I have to give
to shop owner.
Thanks and regards
Swagatam says
Sorry, I have no idea regarding the lamination data….so I won't be able to provide any help.
However, if you happen to build it successfully feel free to shear your experience and data regarding the same, will appreciate it a lot.
style says
One more thing Sir, can you discribe breifly the Dimension of transformer.
Thanks and Regards
Swagatam says
please see the reply given to OKIF in the previous comments.
style says
Dear sir,
What do you mean by "EE core have air gap in end " . if I apply varnish coat on single E E core . Would that gap be enough.
Thanks and regards
Swagatam says
air gap refers to the small gap made by inserting paper or a layer insulation between the end surfaces of the two E core where they merge together.
Rikenz Lalar says
Hai…I'am Lalar…
How do you determine Freq Switchingnya?
And how many Switching Freq and Freq Osc you use on this circuit?
if I can replace the transformer with ETD49 order to get the V out and I out more by scematic this? and how comparisons Primary Coil and Secundernya?
Swagatam says
Hi, frequency is determined by 470k, 1k, 2n2, one frequency oscillator only.
any suitable EE core will do for the project.
OKIF says
Sir, What kind of bobbin do you use to wind the transformer? do you have bobbin dataheet?
Swagatam says
Any bobbin recommended for 15mm EE core can e used, an example image of the E cores can be seen here:
www.hitachimetals.com/images/beta_images/ee_core.gif
B should be 15+15 = 30mm
OKIF says
is it Okay if i use Ferrite Bobbin Core EE22PL3K /Ferrite Bobbin Core EE25R3K ?
Swagatam says
yes, any ferrite core bobbin assembly is ok as long as the winding fits in it comfortably…
Syed Arham says
Sir i have tried that circuit with GPP20j diode but the fuse always broken?
Swagatam says
Syed, if the fuse is blowing it could be due to some other fault in the circuit, not because of the diode….you may have to seek help from an expert for troubleshooting the actual fault.
Ashok Dhenge says
sir i want to make power supply for 1watt LED drive. I want 24 – 36 volt dc supply at 5amp. because i m not electronics knowledge i am not understand coil turn even i don't see what are the material. please can you design another circuit if possible or please guide me or send me video on ashokagreatking06@gmail.com please help me. I already search in your blog also post comment in another post regarding LED drive for ceiling lights.
Swagatam says
Ashok, you don't need to make the power supply, you need to buy it from the market. Your main project is LED lighting not the power supply, so please buy it for the market and use it for your purpose.
Ashok Dhenge says
can we use computer SMPS for supply as i check out SMPS 450watt it gives 12volt 20A. Is it useful as it gives warranty? Is it useful for LED driver?
Swagatam says
yes will do, and now since the LEDs are connected in series, parallel mode the 1.5meter distances will have no effect or minimal effect.
Ashok Dhenge says
ok so sir can now we can connect LED in grid of 0.5m X 0.5m using any computer SMPS. right sir? Thank you for guidance.
Swagatam says
yes can be done as per the series/parallel instructions and the formulas given in the other article..
dragos spirea says
HI! Sir, tell me please number of turns for the primary and secondary auxiliary transformer ETD 29. Wire diameters of bobbin.Not have EE core 15mm
Swagatam says
Hi Dragos, no changes are required it's exactly the same as mentioned in the above article.
Syed Arham says
Diode Type Standard
Voltage – DC Reverse (Vr) (Max) 600V
Current – Average Rectified (Io) 2A
Voltage – Forward (Vf) (Max) @ If 1.1V @ 2A
Current – Reverse Leakage @ Vr 5µA @ 600V
Speed Standard Recovery >500ns,>200mA (Io)
Does it work here, It is standard recovery diode??????
Swagatam says
If it's mentioned "fast recovery" in the datasheet, then it can be surely used.
Syed Arham says
Sir can i use gpp20j instead of ba159..
shopkeeper said that i should work in this circuit..
Swagatam says
Syed please check its datasheet, if it's a 1amp/300V fast recovery type diode then there's no problem using it.
Syed Arham says
Sir can you suggest me any diode instead of ba159 or otherwise i will try other fast rectifier diode..
I have seen a NTC in the ballast circuit of 25 watt CFL ..Can i use that one..
I am waiting for your reply
Swagatam says
Syed, any equivalent fast ercovery diode will do.
yes, the specified NTC could be used
Syed Arham says
Sir BA159 is not available in my city. I have checked all the shops.
can i use any 1000v , fast recovery diode
Swagatam says
yes, any similar 1kv fast recovery type diode will do.
Syed Arham says
Thanks You…
Syed Arham says
Sir,
Is there any way to increase the amp of this circuit..Like 8a or 10a
Swagatam says
Syed, use more number of wires in parallel while winding the secondary turns, this will proportionately double or triple the current rating of the system.
mehul patodiya says
Sir, Give me no of transformer used in your circuit
Swagatam says
The transformer winding details are given in the article.
Syed Arham says
thanks sir…
Syed Arham says
Sir,
the size of the transformer is standard or the transfo which can hold these no. of winding can be used?
Swagatam says
the one which would hold the turns comfortably must be used.
Bojan Jakovljević says
Hello,
is there any way to make this to be variable power supply?
And yes this is one of the best blogs I found for electronic projects!
Best regards.
Swagatam says
Hi, thanks!!
You can try replacing the zener diode with a 4k7 pot and 22 ohm resistor with a 1K resistor, the pot could be used to vary the intensity of the opto LED allowing desired voltages at the output.
The LED anode will go to the center of the pot, the remaining free ends of the pot will connect with 1K and ground.
Bojan Jakovljević says
Thank you kind sir!
Bojan Jakovljević says
Sorry for disturbing again,
but is this transistor near ZD 16-18V in schematic actually part of 4N35?
Swagatam says
It's inside the 4n35, an inside view of the opto.
check the datasheet of 4n35 for getting an exact idea about it.
Md Shakil says
what is the purpose of using R220 2W at output?
Swagatam says
it's for dissipating excess power and for aiding the zener stage, it may be removed though, since the inclusion is not crucial.
Unknown says
Hi,
Nice blog and circuits!
I'm trying to drive a 1/4 hp three-phase motor with an atmega, for which I'll be using this setup:
https://drive.google.com/file/d/0B_0sypSANVUcdDA4SGxEcFpUOHc/edit?usp=sharing
The author told me I'd need 4 separate 12v supplies (3 for the high-side bridges, 1 for all low-side bridges would be fine).
Would it be too complex to split your 12V single-output 5A into 4x12V outputs? It seems I'd need 2A to switch my mosfets, though, being such a design also useful for using igbt's instead in a future.
Regards,
Swagatam says
Hi Thanks! Saw this just now, so replying you rightaway!.
I can't suggest actually until I see the entire circuit diagram, because high/low side configurations could be crucial designs and need special care.
it's always better to go for the extreme safety measures, as much as possible, so using separate power supplies could be preferred
Skl Dj says
dear sir i want to build the smps. i want to know what is Th-NTC used in this circuit?is it possible to use IRF640, or IRF Z44N mosfet in this circuit? can i change the value of the capacitor 10uf 400v with 3.3uf or 100uf…..just i want to know….please reply.
Swagatam says
Dear Skl,
Th-NTC is a 350V NTC thermister.
Only those mosfets which ca handle in excess of 400V will work here, the ones you have suggested won't work
The input filter capacitor voltage should be rate at 400V, anything less will be unsafe.
biannz says
ok sir but if eliminate the EMI coil that mean it should connect straight to the A/C plug? sir i went to electronic shop i asked them to give me ba159 diode but they said it not available only they have does not have a number but it a shape diode can it be use?.
Swagatam says
biannz, you can connect the input directly without the EMI coil, it's there only for suppressing noise.
do not use anything that's not verified or is without a number…..I think your shop keeper sells old used parts ..is it?
biannz says
sir please can i use 1n5404 in place of ba159?
second question please what is EMI coil?
Swagatam says
1N5404 will not work as it's not a fast recovery type of diode.
you can eliminate the EMI coil it's not compulsory.
Indrajeet Singh says
U Can use 4937 in place of BA-159
Syed Arham says
Hi,
can i increase the output volts to 36v or 24v?
Swagatam says
yes you can do it by adding more no. of turns at the secondary side of the transformer.
Swagatam says
.the opto zener will also need to be changed appropriately
abhishek goyal says
thank you sir. this is the best place i found for projects.
please tell me a ckt for smps based 36v,2.5A supply
thanks to you a lot
Swagatam says
thank you abhishek, If possible I'll try to present the design in my blog soon.
Justin Adie says
Hi
Is there any reason why this kind is switched topology can't be used as a (constant voltage) power supply rather than a charger?
Swagatam says
Hi,
a charger is also a kind of power supply so definitely smps circuits can be used as DC power suppies.
in fact smps itself stands for "switch mode power supply"