12V, 5 Amp SMPS Battery Charger

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..

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Comments

Justin Adie said…
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 said…
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"
Syed Arham said…
Hi,
can i increase the output volts to 36v or 24v?
Swagatam said…
yes you can do it by adding more no. of turns at the secondary side of the transformer.
Swagatam said…
.the opto zener will also need to be changed appropriately
biannz said…
sir please can i use 1n5404 in place of ba159?

second question please what is EMI coil?
Swagatam said…
1N5404 will not work as it's not a fast recovery type of diode.
you can eliminate the EMI coil it's not compulsory.
biannz said…
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 said…
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?
Skl Dj said…
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 said…
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.
Unknown said…
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,
Md Shakil said…
what is the purpose of using R220 2W at output?
Swagatam said…
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
Swagatam said…
it's for dissipating excess power and for aiding the zener stage, it may be removed though, since the inclusion is not crucial.
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 said…
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.
Syed Arham said…
Sir,
the size of the transformer is standard or the transfo which can hold these no. of winding can be used?
Swagatam said…
the one which would hold the turns comfortably must be used.
mehul patodiya said…
Sir, Give me no of transformer used in your circuit
Swagatam said…
The transformer winding details are given in the article.
Sorry for disturbing again,

but is this transistor near ZD 16-18V in schematic actually part of 4N35?
Swagatam said…
It's inside the 4n35, an inside view of the opto.

check the datasheet of 4n35 for getting an exact idea about it.
Syed Arham said…
Sir,
Is there any way to increase the amp of this circuit..Like 8a or 10a
Swagatam said…
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.
Syed Arham said…
Sir BA159 is not available in my city. I have checked all the shops.
can i use any 1000v , fast recovery diode
Syed Arham said…
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 said…
yes, any similar 1kv fast recovery type diode will do.
Swagatam said…
Syed, any equivalent fast ercovery diode will do.

yes, the specified NTC could be used
Syed Arham said…
Sir can i use gpp20j instead of ba159..
shopkeeper said that i should work in this circuit..
Swagatam said…
Syed please check its datasheet, if it's a 1amp/300V fast recovery type diode then there's no problem using it.
Syed Arham said…
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 said…
If it's mentioned "fast recovery" in the datasheet, then it can be surely used.

dragos spirea said…
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 said…
Hi Dragos, no changes are required it's exactly the same as mentioned in the above article.
Ashok Dhenge said…
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 said…
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 said…
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 said…
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 said…
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 said…
yes can be done as per the series/parallel instructions and the formulas given in the other article..
Syed Arham said…
Sir i have tried that circuit with GPP20j diode but the fuse always broken?
Swagatam said…
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.
OKIF said…
Sir, What kind of bobbin do you use to wind the transformer? do you have bobbin dataheet?
Swagatam said…
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 said…
is it Okay if i use Ferrite Bobbin Core EE22PL3K /Ferrite Bobbin Core EE25R3K ?
Swagatam said…
yes, any ferrite core bobbin assembly is ok as long as the winding fits in it comfortably...
abhishek goyal said…
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 said…
thank you abhishek, If possible I'll try to present the design in my blog soon.
Rikenz Lalar said…
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 said…
Hi, frequency is determined by 470k, 1k, 2n2, one frequency oscillator only.

any suitable EE core will do for the project.
style said…
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
style said…
One more thing Sir, can you discribe breifly the Dimension of transformer.
Thanks and Regards
Swagatam said…
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.
Swagatam said…
please see the reply given to OKIF in the previous comments.
style said…
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 said…
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 said…
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 said…
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 said…
Hello Sir .
I will give all data whaterver I had to your email I'd within couple of days
Regards
Swagatam said…
no problem style, take your own time and do it nicely :)
Nitesh Agrawal said…
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 said…
use a 15V zener in place of the shown 13.5V zener
Nitesh Agrawal said…
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 said…
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 said…
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 said…
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.
Indrajeet Singh said…
U Can use 4937 in place of BA-159
xavier Pereira said…
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 said…
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 said…
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 said…
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.
Muhammad Munir said…
Dear tell me the complete action of circuit. why u did not used any pwm controller like uc3842,sg3525,tl494.
Jideofor Igwe said…
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.
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 said…
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
Nitesh Agrawal said…
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 said…
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 said…
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.
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 said…
Hello spoorti, presently i do not have this circuit with me, if I get it will surely publish it for your reference.
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 said…
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
Rentanu said…
This circuit have under test before? i will try it for my project, thank you sir

Regard
Swagatam said…
yes it is a tested design, but it is not recommended for the newcomers
Nirvikal Lal said…
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 said…
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.
TonyBen said…
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 said…
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
Raymond Michael said…
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 said…
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
adam ubaid said…
plz
choper ki calculation kese hain???????????????
bataein plzzzzzzzzzzzzz
adam ubaid said…
transformer calculations plz
btaein
adam ubaid said…
choper ferrte calculations kya hain??????????////
Swagatam said…
the details are given at the bottom section of the article
Supun Fernando said…
what is meant by 6A4*2 diodes? do i need to make diode bridge or can i use single diode?please help sir....
Supun Fernando said…
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 said…
those are 6 amp rectifier diodes
Swagatam said…
you can use a single 10amp diode, preferably it should be a Schottky diode
Supun Fernando said…
is there a replacement cap for 2.2n 100v? plz help sir..
Swagatam said…
use two 1nF/100V in parallel
Supun Fernando said…
Thanks for this circuit. it works really well and thanks for your advices..
Swagatam said…
you are most welcome!
Amrut Ubare said…
Thanks in advance, I would like to know about design of ferrite core transformer (ferrite core size), please help me sir.
Swagatam said…
thanks...it's 15mm, the details are furnished in the article.
psa said…
can i tweak transformer's secondary side turns and parallel wires to get 60volt 50amps as output from this circuit
Swagatam said…
60V is possible but 50 amps is extremely high, I am not sure about it.
psa said…
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 said…
yes, according to me that's definitely possible.
psa said…
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 said…
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.
psa said…
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 said…
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
Raymond Michael said…
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 said…
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 said…
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""
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 said…
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 said…
Hi Jamal,

yes, the mosfet could get significantly warm! A heatsink would be recommended
Kausik Dana said…
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 said…
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 said…
...you'll need a 25-0-25V trafo with 3 amp current capacity
Kausik Dana said…
Many thanks Swagatam. I will make one.
Naufan said…
Sir, instead of using EE Core. Can i use Toroidal Core?
Can i replace the BA 159 With 2X 1N4148 In Series?
Swagatam said…
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 said…
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 said…
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 said…
Yes, but sir, can 1N4148 diode handle up to 1KV of Voltage and 2A of Current?
Swagatam said…
1n4148 won't work it seems, you can try any other adequately rated fast recovery rectifier diode.
leonardo cuello said…
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 said…
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 said…
Hi, thanks for your reply! I'll try with these diameters and I will comment the results.
regards
Swagatam said…
OK, great, thanks!
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
Javad Farokhi said…
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 said…
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
Swagatam said…
OK you can send it to my emal ID
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 ??
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 said…
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 said…
4n35 has only four legs, so the base is not applicable in the device.....
thx sir, sir i want to ask again, what the function from NTC thermistor?
and should i use 10k NTC?
Raymond Michael said…
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 said…
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
Swagatam said…
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 said…
...the 22 ohm resistor will also need to be replaced with a 10k resistor.
ashwani mishra said…
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 said…
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.
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 ??
when i need more current output about 10-20A, what should i need to change on the schematic? ???
Swagatam said…
yes pc817 will do.

the trafo winding specs must match the indicated data, otherwise it won't work
Swagatam said…
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
Paras Thakkar said…
sir what is T2.5A is that a fuse.
Paras Thakkar said…
sir what is the specification of BJT near ZD 16-18V .please reply
Swagatam said…
it can be a BC547 transistor
ashwani mishra said…
sir, can i use this circuit for charging car battery
zahidsre1288 said…
hello sir i need mobile phone charger circuit diagram 220v ac to 6.0 dc volt transformer less.
Swagatam said…
it's already posted in this blog, pls use the search box to find it.
Parag Karekar said…
Hello Sir, How can I do calculations of transformer?
i.e. Number of turns, core size, core material and wire gauge
Swagatam said…
Hello Parag, the details are given at the bottom section of the article.
sebi davis said…
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 said…
Sebi, you can try playing with the above explained design and see whether it works out for you or not?
afam nzoiwu said…
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 said…
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.
Rahul Arya said…
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 said…
Dear Rahul, That can be extremely difficult to judge, sorry I can't specify without practically seeing the entire schematic.
Raj said…
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 said…
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
style said…
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 said…
style you can try a 5 ohm 11mm NTC
rutvij patel said…
Dear Sir,
Can i use this smps for camera supply 24*7 days
MOHD SHAHID said…
sir
i wanna make this circuit using viper-27 what would be the reading of the capacitors for this.
Swagatam said…
Dear Rutvi, yes you can use it only if the camera volts specs matches the circuit's output volt specs.
Swagatam said…
Mohmd, is the Viper27 rated at 5amps?
rutvij patel said…
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 said…
It is an SMPS design, and it will work for 12V 2 amp applications also.
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 said…
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

Ainsworth Lynch said…
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 said…
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
Aghos said…
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 said…
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
Abobaker Atef said…
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 said…
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 said…
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 said…
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 said…
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..
Swagatam said…
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
Swagatam said…
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.
aamin007 said…
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 said…
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
Ezequiel said…
Hi, Sir. Since there are several ferrite cores, I'll appreciate more info about the ferrite core. Like the measures. Thanks! Excellent job.
Swagatam said…
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
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