The following content explains a simple 12V, 1 Amp switch mode power supply (SMPS) circuit using the very reliable VIPerXX IC from ST microelectronics.
Overview
With the advent of modern ICs and circuits, the age old iron transformer type of power supply are surely becoming obsolete. Today power supplies are much compact, smaller and efficient with their functioning. Here we discuss one outstanding switch mode power supply circuit which can be easily built at home for deriving clean, ripple free 12 V DC.
Thanks to ST Microelectronics IC, the VIPer22A, which has made the construction of truly efficient and compact SMPS power supply unit possible that too by using a very few number of electronic parts.As can be seen in the picture, the circuit is indeed very small, compared to the power that is available from it. It's just 50 by 40 mm in its dimensions.The circuit diagram is very easy to understand, let's study it with the following points:
How the SMPS Circuit is Designed to Work
Looking at the figure we can easily see that the configuration does not involve too many stages or parts.
The input mains AC, as usual is first rectified using ordinary 1N4007 diodes which is fixed in the bridge network mode.
The rectified high voltage DC is filtered using the high voltage capacitor.
The next stage is the crucial one which incorporates the outstanding chip VIPer 22A manufactured by ST Microelectronics.
The IC alone functions as the oscillator and induces a frequency of around 100 KHz into the primary winding of the ferrite E core transformer.
The IC is absolutely rugged and is internally protected from sudden voltage in rush and other voltage related component hazards.
The IC also incorporates built in over heat protection which makes the IC virtually indestructible.
The voltage induced at the input is effectively stepped down at the output winding, due to low eddy current losses, about 1 amp current becomes available from a relatively tiny ferrite transformer.
With the coil specs shown the voltage is around 12 and the current is around 1amp.
A special feedback circuitry is also included in the circuit for maintaining high degree of protection and power saving features.
The feedback loop is implemented via an opto-coupler which becomes active during abnormal circuit conditions.
When the output voltage tends to rise beyond the set threshold the feed back loop becomes operative and feeds an error signal to the IC FB input.
The IC instantly comes into an corrective mode and switches off the input to the primary winding until the output returns to the normal range.
Circuit Diagram
PCB Layout
Transformer Winding Data
Another 12V 1 amp simple SMPS using IC TNY267
How it Works
The simple smps circuit shown above uses the popular tiny switch IC TNY267. It is a tiny mosfet based 120V to 220V switching oscillator IC which only requires configuring with a ferrite transformer and a stepped down Vdd operating voltage.
The design is so simple that a mere visualization of the schematic is enough to tell us the functioning details quickly.
The stepped down start voltage is acquired from stabilizing network using a 180V zener diodes and the fast recovery diode BA159 after rectifying the mains 220V through a 1N4007 diodes and the 10uF/400V filter capacitor.
As soon as this voltage is applied to the IC, it begins oscillating and its internal mosfet begins switching the ferrite transformer primary at the predetermined oscillating frequency.
Being a flyback design, the secondary also starts conducting during the OFF cycles of the primary through mutual induction and generates the required 12V voltage at the output side.
This voltage may not be stabilized, therefore an opto-coupler based feedback is used and the link is configured with the exclusive shut down pinout 4 of the IC.
This ensures that the output never exceeds, and remains fixed at 12V 1 amp proportion.
Transformer Winding Data
The transformer winding is actually quite straightforward, and may be done in the following manner. Keep in mind that the black dots indicate the start points of the winding which is very important, and must be strictly followed while winding the transformer.
The primary wound using 36 SWK super enameled copper wire upto 150 turns, while the secondary is wound using 26 SWG wire upto around 12 to 15 turns.
The core can be a standard E19 type ferrite core having a bobbin with central core cross section area of approximately 4.5mm by 4.5mm.
mahmoud says
Hello,
Can I use the viper12a instead of viper22 in the circuit?
Swag says
yes you can but the output current will be reduced to 350mA
Babboo says
25 years back if you had asked me to repair any transistor radio, even the ones that came tied in a gunny sack with thousands of pieces – I WOULD HAVE GUARANTEED ITS REPAIR to its near original state. NOW i AM ONLY WATCHING my younger brethren making things work, and believe me I enjoy a lot because they modt certainly stir up whatever grey cells are left up in my brain. Recently a similar smps circuit repaired by some one on you tube employed 8022 (either AP 8022 or AD 8022, i cant say) and repaired a 12V 1A smps supply. I have seen the application circuit on the manufacturers’ site and wish someone could make and tell me in such details as the instant example. Is anybody watching?
Okeya Boboye says
Hello please I am trying to build a battery charger with this smps.
I want to obtain 12V, 3A for the output.
Input would be about 220V, 50Hz.
How can I manipulate your design and also select the right material, that will give this requirement?.
Thank you
Swag says
Hello,
sorry higher current than 1 amp may not be possible from this design unless voltage output is reduced below 12V, because the IC is rated to handle a maximum of 1 amp
Krishnam says
Is the specific transformer available in market? Or have i to design it myself?
Swag says
as far as I know it is not available in the market, you will have to build it according to the specified details
Adrees mohmand says
Hi sir.
This blog make my problem easy. but i have a question. if i increase the winding turn in parallel for achieving high current at output i-e (7A-10A), while keeping remaining circuit unchanged. Is this is possible.?
Swagatam says
Thanks Adrees, sorry that may not be possible because the mosfet inside the IC itself is not designed to deliver that much current, the maximum rating being just 1 amp
Faiq Ahmed says
can you please understands me the feedback with voltage refrance how it works to regulate the voltage? also tell this topology is DCM or CCM .one more thing how this ic can use tfor both modes interchangeabily
Swagatam says
Plaese refer to the datasheet of the IC for a detailed information about the design
application-notes.digchip.com/005/5-10593.pdf
Harish Kr Singh says
Hi, please tell me how to modify this circuit & transformer to make 24V DC/500mA output?
1. Will it work if I double the secondary winding and primary & auxiliary remain the same as in above circuit?
2. I'm planning to replace 7805 with 78L05 that will lower the output current to 5V/100mA, this will increase maximum current of 24V output. will this work?
2. Should I need to change value of L2, R3 or any other discrete component?
Swagatam says
Hi, yes that's possible, you can try increasing the secondary turns to around 30 turns and also tweak the R6/R7 values to get 24V…a 780L5 can be used for restricting current, but a better way would be to make sure that the load connected with 78L05 is itself not rated to consume more than 100mA…
FHATUWANE KINGSLEY Tshiovhe says
Hi. can I still use LNK623 instead of using viper22a??
Swagatam says
It cannot be used in the above design, LINK switches have their own specific circuit which you can follow
FHATUWANE KINGSLEY Tshiovhe says
Hi, can I buy that transformer at any electronics store or I have to build it myself???
Swagatam says
Hi, you will need to build it yourself or get it made-to-order, ….it's not available ready-made.
Faiq Ahmed says
Aoa how r u? Brother i have made it but problem is that it show 12 v on DMM but when i connect with led light it drop to 8 volts .where is problem?
Swagatam says
Hi Faiq, what is the voltage and current specs of the LED??
Please note that the transformer is the cubical element in this design and in fact that's true in all SMPS designs….so make sure you have built the transformer with utmost accuracy….if possible please get it build from a professional winder…
Swagatam says
sorry there's a typo in the above comment….I meant to say crucial and not cubical…
Anonymous says
Sir, whether supply should be 230v or what?
I mean i gave 230v supply and thermistor blowed off. What shoulf i do??
Swagatam says
yes it is designed to work with 220V mans, I think you might have done something wrong in the design…get a professional help from any nearby source
Unknown says
Sir. What does chassis ground mean and how is it different from ground symbol?
N how should i connect the chassis ground terminals in practice connection?
Nitishkumar Ar says
What is chassis ground?
How is it different from the normal ground? N how should I connect the chassis ground terminals in practical connection?
Swagatam says
chassis is supposed to be the metallic cabinet inside which the circuit is housed.
the negative line of the circuit is supposed to be connected with this metallic cabinet, and the metallic cabinet in turn is supposed to be connected to the mains earth pin via the mains cord.
Madubuze says
Hi Swag!
What is that symbol that seems to be an “E” facing down? Is that the chassis ground symbol?
Swag says
Hi Madubuze, yes that’s the symbol for the chassis connection
Mark Anthony says
Ok.tnx for advice.ill try that one.
Swagatam says
Hi Mark, I am not sure exactly what you are intending to make, I guess the following circuit might be more suitable to your need
https://homemade-circuits.com/2011/12/simple-led-automatic-daynight-lamp.html
Mark Anthony says
I gave up on modifing the already made smps and returned it to my friend.instead ill copy your design.
https://homemade-circuits.com/2011/12/cheap-yet-useful-transformerless-power.html
with 12v(load)led in series and ldr in the middle. I have some question.
Do i need to adjust or raise the voltage so that the led would make its highest performance? My parts are
Ldr
Transistor npn
100k variable resistor
1k resistor
Is it ok to add regulator ic.lm7812.i got some spare.just for added protection.
Mark Anthony says
Good day to you sir..
Can you pls help me design an smps for 12volts for an led with label dw-5630-6led-2b3c. With an LDR switch.
Im a newbie on electronics and wanted to learn more.cheaper parts would be much appreciated.
Swagatam says
Good day Mark, please tell me the voltage and current specifications of the LEd, you can get it from the datasheet of the part, that will help me to understand your requirement in detail
Mark Anthony says
Quantity: 3; Emitter Type: 5630 SMD; Total Emitters: 6; Power: 3 W; Color BIN: White; Rate Voltage: 10 V
Mark Anthony says
The current is 1amp.i have many question and problems.hope you could help me learn more..
Swagatam says
dividing 3 by 10 gives 0.3 amps
multiplying it by 3nos gives around 1 amp.
It means you can use the SMPS circuit that's explained in the above article for your need…
R6 or R7 can be suitably adjusted for reducing the 12V to 10V
Mark Anthony says
Tnx for your help… can i ask what is the voltage needed for the ldr?
Swagatam says
you can connect the LDR in parallel with R6, during daytime this combination will hopefully keep the opto switched ON and the SMPS output switched OFF
Mark Anthony says
Tnx for your help sir.. your ideas are great.
Swagatam says
you are welcome!
Mark Anthony says
Good day to you sir swagatam..
A new problem came up.
When my ldr is lighted and decreases risistance the smps increases its voltage.thats the reason why my led wont go totally off.does putting a regulator would help(lm7810) solve the issue?
Hoping to learn more from you sir..
Tnx
Swagatam says
Mark, manually experiment by changing the R6 or R7 values and identify which adjustment causes the most effective disabling of the output…you can then put the LDR in parallel with that resistor for the required response
Mark Anthony says
Sorry to cause you so much trouble.but actually the smps i was refering to was an already made one.with some smd type of parts.
Is there a way i can modify it outside the already made smps??
Swagatam says
in that case you can use an external light activated switch such as this one:
https://homemade-circuits.com/2012/01/how-to-make-light-activated-day-night.html
Swagatam says
modifying the smps circuit could be difficult without studying the stages carefully
Jeran Toledo says
Sir how to make power supply 12v. With switch
kakipancingMUAR bandardiraja says
hello sir,
thank for the great sharing.
from the circuit i see the out is 12V and another voltage regulator at 5V.
what is the current for 5V?
i want to build a PSU, for 12v 1amp and 5v 2amp. if i can combine the circuit. it will be superb.
thank you in advance for guide.
Swagatam says
thank you kakipancingMUAR
the shown 5V would be also producing a max current of 1 amp.
5V 2 amp could probably be achieved by extracting a calculated tap from secondary and terminated out without a 7805.
ASPERO Research says
how to calculate Transformer parameter to increase current?
Sujit Chavada says
Hello Sir,
I am new in SMPS design. I am facing a problem in this SMPS. SMPS remain ON for 15 second, after that it going to OFF for 7 second, again ON for 15 second and again OFF for 7 second. Such cycle continue. In ON condition, it giving 13.8V and in OFF condition it giving 0.8V. I apply 12V/100mA DC motor as a load. Kindly help me in this problem.
Thank You,
Swagatam says
Hello Sujit, It would be difficult to understand the issue precisely, but normally this would happen if the IC is going in the shutdown mode due to overheating or over current.
This would most probably happen due to a wrongly configured transformer….check the inductance of the primary it should match the given specification.
also add a small heatsink with the IC.
pankaj pandey says
hello sir,
how are you sir…after a long time i am here again with my another quarry …dear sir I have a inverter and it is giving me some problems…the problem is regarding to its charging function…earlier it starts trickle charging to the battery..when voltage reaches to 14 volt..but now it does not cuts the power after full charging of the battery…when the battery fully charged …then inverter makes humming sound and burnt the ac fuse..
So kindly help me about the problem..
Thanks a lot
Pankaj pandey
Swagatam says
Hello Pankaj,
it would be difficult to judge without a practical diagnosing. most probably the relay associated with the full charge cut off circuit is responsible for this….it could be correctly tripping at the full charge level but in the process shorting something through its other pair or contacts.
check the response of the relay by supplying a varying voltage through a variable power supply across the battery points (without any batt connected)
Krunal bhongade says
Hi Swagatam,
Thanks for great tutorial.
I am trying this circuit and getting the result.
Now I am drawing 80mA of current at 12V through this circuit and it works perfectly. But when I increase the load to 150mA, the ST Viper22A gets too hot and cuts the supply for some time so the output voltage falls from 12V to 2V. After sometime it again starts supplying 12V.
The IC is getting overheated and it trips. Could you please suggest something.
Thanks in anticipation.
Swagatam says
Hi Krunal, this circuit is rated to handle upto 1 amp, so 150mA shoudn't be a problem at all, not sure what might be causing this, most probably if the transformer is not built correctly could cause the circuit to malfunction, so it could be your trafo that's not correctly wound, please check it again and if possible take the help of a professional winder.
the above design is by STmicroelectronics so it should be perfectly correct with its data, for more info you can visit the original website from the given link in the article.
Krunal bhongade says
Hello,
Thanks for the reply.
I had given this transformer winding data to a professional manufacturer from Delhi and he has built it using the same data. Moreover the transformer is not at all heating up but its only the IC to heat up. I checked the voltage at Vdd of IC which I found to be -2V which seems to be wrong(still the output vtg is 12V), also the output of the rectifier is just 5V. All the components are cool while the IC is heated up.
Any suggestions.
Krunal bhongade says
Can you please tell me what are the expected voltages at few test points so that I can debug the circuit.
Krunal bhongade says
Sorry for wrong readings. I was taking wrong reference ground.
The voltage at Vdd pin of Viper22A is 12 VDC and
voltage across rectifier capacitor (47uF/400V) = 318 VDC
Swagatam says
The transformer will not heat up, it is the fet inside the IC which will heat up if the winding are not correctly wound….especially theprimary winding is the one which will can make the IC hot if not wound correctly. According to the data the inductance of primary winding must be 3mH, please confirm this first…moreover all the winding has polarity which can also create an issue.
I am not sure about the voltages at different points, and is basically not required to be checked, because if the winding is correct and the IC is genuine then the circuit should work at the first go….considering the connections are all OK.
Krunal bhongade says
Hi, Thanks for all your suggestions.
Can I just reverse the primary winding and check? Will it cause any problem?
Also I do not have any LCR meter to check inductance.
I have ordered my components from element14 so IC should be genuine.
Also I am getting 12V at the output upto 80mA, so I think the connections are also OK.
Please suggest.
Swagatam says
Hi, I think it can be tried, you can reverse the primary ends with the circuit and see the effect…however checking the inductance is more important as that would quickly help to solve the issue.
Krunal bhongade says
Hello, Good Morning.
I checked by reversing the primary ends, but this time I was not getting any output voltage at the output.
I have asked my friend to measure the inductance of it, and will update here after I get result.
Also, I would like to know if the IC is only used for switching, can I replace it with another MOSFET or optocoupler and driving it with 60KHz using LM555.
Also, I am not able to understand how the auxiliary winding is able to supply 12V to this IC.
I would like to know your experienced suggestions.
Thanks in advance.
Swagatam says
Good morning, The above circuit cannot be modified in anyway and is not recommended, if you want to use discrete parts for the making the same design then you can try the following circuit:
https://homemade-circuits.com/2013/10/12v-24v-1-amp-mosfet-smps-circuit.html
the internal circuitry of the IC is initially switched ON through the drain connection, which internally applies a triggering voltage to the Vdd (@1mA), this action switches ON the mosfet which in turn causes the auxiliary winding to kick and apply a rising unregulated voltage to Vdd…when this voltage exceeds the internal limit, the internal regulator switches OFF, causing the mosfet and the IC to switch Off….the cycle now keeps repeating the sequence at around 60kHz
Krunal bhongade says
Hello, So I got the measured inductance and is only 0.046 mH.
I don't understand why my manufacturer did not paid attention to this.
What should I do now? Will it work just by adding an inductor in series?
Swagatam says
Hi, you should get it done afresh and this time from a qualified winder who knows how to measure and assign the inductance values to the coils, because it seems this trandfrmer could have many winding errors .
adding a series coil will not do.
If you are in Mumbai get it done from Lamington road.
or if you have the access to a hand winding machine you can try it yourself at home.
Krunal bhongade says
Ohh, I am overwhelmed with your detail description, Thanks.
Yes, I think I have to look for another winder.
I am working in very rural area of Rajasthan without any access to advanced things except internet (Thank GOD). Also I have never been to Mumbai before. Still I would try to do something.
I am doing this as for my hobby. It would be really nice if you can suggest some winder.
Thank You very much for all your help.
Regards,
Krunal
Swagatam says
You are welcome Krunal, I hope you get the issue resolved as soon as possible.
winders can be difficult to find online, alternatively you can try it winding by hand… with a lot of care and patience you could possibly succeed with it.
lokesh lokesh says
Hello sir plzz plzz do update same sort of post on FB.. Instead of here..
in Fb we can comment and have ur reply notification here really feeling hectic to find reply or comments back..
even for typing..
since this method is not much user friendly and transparent. it my suggestion
on behalf of everyone I am requesting u since some of my (electronic hobbyist) friends are having same opinion.. as most of us don't use Email and this website much compared to Fb and WhatsApp in there phone..
I respect ur knowledge and patience so I wish its being utilised to everyone in proper way..
i hope my msg convinced…
seeking for your valuable reply. .
Thank you regards your Fan Lokeshelectronic
Swagatam says
Hello Lokesh, I appreciate your emotions, however since this is my site so I will want visitors to come to my site, not to some external site like facebook.
moreover it's not at all difficult to comment and receive replies from my site…you just have to tick the "notify me" box and all my replies will reach straight to your email.
even anonymous readers can post questions here
Aqilah Zainuddin says
Hello Sir. Would you mind sharing your PCB in PDF file? Thank you Sir 🙂
Asket Bhullar says
Soooooory… its TRUE !
Asket Bhullar says
3 pin triac is not IC . Any chip with 4 or more pins is called IC, this is what I learned. No intention of insult pl. But I like Ur up-frontness, pl never hesitate for what ever comes to ur mind, Love U !
Swagatam says
sorry I am not sure to which comment you are addressing to?? but answering to your suggestion I must say that a 3-pin device can also be an IC….take for example 7805, 7812, TL431 these are all ICs.
Asket Bhullar says
I'll get back 2marow.What do u feel about the bleeder resist after the MOSFET !
Swagatam says
mosfet is inside the IC
Asket Bhullar says
Thanks Bud, let me check up. Other thing which came to my mind to check the bridge diodes indevudaly . I,ll get back on the outcome.
Swagatam says
yes buddy that's right, if the diodes are faulty it might send AC instead of DC to the caps and blow them of
Unknown says
I am Office Automation Techi, I have a problem with one power supply SMPS, there is a 470 mfd 400v capacitor after bridge rectification on A/C side getting blown even after changing the MOSFET along with it. Its blown thrice even after checking the rest of circut. It is further found that MOSFET is not burning.
Swagatam says
check the voltage across the capacitor points, if it's exceeding 400V then that might be causing the explosion….if voltage is not the issue then probably you can try a non-polar capacitor and see if it works…a bad quality capacitor can also be the culprit
Bharat Surani says
Hello Sir
currently we are using original ST L7805, the issue with it is, we converting 12v DC to 5v DC for consumption of up to 50mA. After putting it on testing we come to know that L7805 is heating too much, temp is not being measured yet, but it is enough to burn up your finger, will it make any kind of damage to further circuitry or L7805 will burn out within small life time?
Swagatam says
Hello Bharat, if it's getting hot at 50mA then either the IC is not original (faulty) or there's some mistake in the connections.
Please measure the current using an DC ammeter in series with the load.
78XX can never get burning hot since they all have an internal thermal protection facility which don't allow their case temp to go beyond 100 C
when hot the IC will simply cut of the supply to the load and shut down itself until the heat reaches within the tolerable limits
Bharat Surani says
Yes sir, I have both kind of 7805, the original one and fake identified by it's heat sink thickness. Both are getting warm up, where in the connection, I have 12V at pin1, Gnd at pin2 and 5V output at Pin3. I'm using 12v 1A ready made power adapter as source and converting it to 5V for controller. Is there any corrections needed?
Swagatam says
Bharat, please check the output current consumption, I am sure it cannot be just 50mA..please confirm this.
Bharat Surani says
Sir, I'm double sure about the consumption, I have also studied the datasheet of components used. It is not exceeding 50mA.
Swagatam says
at 50mA any 78XX will not become burning hot according to me. Not sure what could the fault in your case.
Bharat Surani says
Sir, is there any other connections needed? around 78xx.
Swagatam says
left pin is input, center is ground, and the right side pin is the output for the load, that's all is required for getting the results from this chip….no further connections are required.
Bharat Surani says
Ok thank you sir for reply. One last que. is there any specified life time of ST L7805?
Swagatam says
thanks bharat, if the IC is operated within its specified tolerable limits then it can go on almost forever.
Bharat Surani says
Thanks a lot for suggestions sir.
VISHAL says
Ok. If possible please suggest any other IC for range 80-300 Volt AC.
Also do you have any tutorials related to Photodiode Interfacing. I am facing a lot of fluctuations while designing Signal Conditioning Circuits for BPW34
Swagatam says
sorry, I do not know about any SMPS IC with that input range.
You can try LM567 IC for signal conditioning of the photo diode.
VISHAL says
Thanks for your reply.
How can we achieve 80 to 300 Volt Range. What changes to be done in above circuit for desired Range
Swagatam says
that might not be possible because the IC is rated for 85V to 285V operation, which cannot be changed.
Swagatam says
…actually it's 265V and not 285V, so it's even less than what I mentioned
VISHAL says
Hello
Can we use the above circuit with an Input AC Voltage range of 80 Volt AC to 300 Volt AC with Output Voltage Constant 12 Volt, 1 Ampere.
Swagatam says
the operating range is from 100V to 285V
Krunal bhongade says
Hey Swagatam,
Really good Job, I really appreciate it.
I am an electronics designer and was looking for such design. I really liked it.
But can you please suggest me which transformer you had used for this. Is it ferrite transformer. Can you please tell me where can I buy this transformer or at least its part number.
Thanks in advance.
Swagatam says
Thanks Krunal,
The circuit is by STmicroelectronics and indeed it looks superb.
the transformer is built over ferrite cores since it's an SMPS design, however the transformer cannot be procured readymade, you will have to build it as per the shown data.
The wire, bobbin and the cores can be easily procured from your local electronic spare part retailer….or if you are in Mumbai you can get these from Lamington Road.
Krunal bhongade says
Hello Swagatam,
Thanks for the reply.
Actually I am from Nagpur and now working at Rajasthan in rural area, Here I could not get them.
Still I have asked my friend from Mumbai & expect to get them soon.
Once again Thanks for your help.
Regards.
Swagatam says
You are welcome Krunal!
Unknown says
Sir, can you please tell me how to design PCB for this circuit. I tried designing the same circuit using Proteus but can't find transformer package in it.
Swagatam says
A professional PCB designer will be able to do it for you….
kiran kamat says
Hi, can this be used 24×7 the whole year
Swagatam says
yes, it can be used continuously…and infinitely
bhavesh nandaniya says
but sir pic 817 has 4 terminal
Swagatam says
check the datasheet:
www.farnell.com/datasheets/73758.pdf
Bhavesh Nandaniya says
Sir have y any circuis 12 v 2 amp and 4amp and not much part in the circuit?
Swagatam says
bhavesh, you can try the following design:
https://homemade-circuits.com/2014/03/12v-5-amp-transformerless-battery.html
bhavesh nandaniya says
sir can i chang amp??
Swagatam says
No current cannot be more than than 1 amp
Bhavesh Nandaniya says
Sir how may tuns includ in secandry need 2 amp??
Swagatam says
2 amp cannot be achieved with this IC, because 1 amp is the maximum limit from this IC, still you try winding two strands of wire together in parallel for the secondary turns and check the response.
Unknown says
hai,
I am new, I designed this above circuit. I got some issues VDD Voltage is 4.1 v some viper is not switching,
can any one guide me.
thanx
Shaikh Fahad says
hi sir,
i m facing problems in calculating primary , secondary and auxiliary winding's.please help me to calculation of exact winding's for 5 V,1 A smps.
Kindly reply as soon as possible.
thank you
Swagatam says
Shaikh, you just have to vary R6 for getting any desired voltage in the range…the winding can be as suggested in the article.
Bharat Surani says
Hello Sir
I got the current value by changing transformer winding's SWG, but one more problem has taken place, that SMPS is getting too hot, and after that it is restarting it self.
What can be the problem?
Swagatam says
Hello Bharat,
I think the transformer is not wound correctly, please see the black dots those indicate the "start" of the winding….. did you follow those correctly?
the IC will reset if it detects overload…. which could be either at the output in the form of an actual overload or a wrongly wound primary….
Swagatam says
OK got it….alternatively you can attach a small aluminum heatsink over the IC…this will stop the circuit from resetting….
Bharat Surani says
it is around 50 mA per relay and I have only used 7 relays.
Swagatam says
that's equal to 350 mA which is perfectly within the range of the design…it would be difficult for me to troubleshoot it from here…
the winding has polarity (start/finish) and that can be crucial, please check it and also try rewinding the secondary by using two strands of wire in parallel instead of one.
Bharat Surani says
Hello Sir
I have implemented same design on PCB. I'm facing some problem. Like 5 V are coming perfectly on controller board, but when I connect relay board with it, and switch any two relay even, power supply is getting restart. Why this is happening so, i did't got any reason, can you pl help us?
Kindly reply as soon as possible.
Swagatam says
Hello Bharat,
check the current consumption of the relay coil, by connecting a DC ammeter in series with the relay coil.
or may be you have not made the circuit correctly as per the given instructions.
Shaikh Fahad says
hi sir,
i m facing problems in calculating primary , secondary and auxiliary winding's.please help me to calculation of exact winding's.
Kindly reply as soon as possible.
thank you
Swagatam says
Hi Shaikh,
all the details regarding the trafo winding are furnished at the bottom of the article, please click on the last diagram, you'll find all the required data and the related layout diagram.
Shaikh Fahad says
hello sir,
i have design same circuit 12v,1 Amp SMPS. But the problem is when i connect the load and it will consume more then 100mA current then voltage get drop to 11 volt.so could i maintain constant voltage 12 volt along with the load. or if voltage drop does it effect on stability.
Swagatam says
hello shaikh,
that should not happen, if you have made it exactly as explained above then the smps should be able to withstand full 1 amp current… at 100mA the voltage should not drop…
the wire gauge determines the amp capacity of the smps, are you sure you used the specified wire dimensions?
Bharat Surani says
Can I got for SR2100?
Swagatam says
yes it will do.
Bharat Surani says
well in that case 1N4007 will also be fine… rihgt?
Swagatam says
1N4007 is not a fast switching diode, BA159 is a fast switching diode.
But I have seen many SMPS use ordinary diodes such as 1N5408 etc at the output so you can try a 1N5408 which is same as a1N4007 but much higher in amps.
Bharat Surani says
and about, BA159 is of 1A only. Will it be fine with replacement of 2A schottky diode?
Swagatam says
you can test it, if it heats up then we can look for some other option.
Bharat Surani says
Is there any other option for increasing current?
Swagatam says
the IC is specified to produce not more than 1amp, so it's not possible
Bharat Surani says
is there any replacement of D8-STPS2H100? As it is not available in market.
Kindly reply as soon as possible.
Swagatam says
Google for "700v mosfet", you will find many options to choose from….any mosfet with 700V and 5 amp would be ok
Swagatam says
sorry… please ignore above comment
you can try a BA159 diode
Swagatam says
1amp is the max current which cannot be increased with this IC
Bharat Surani says
Hello Sir
How can I increase current rating?
Bharat Surani says
Hello Sir
Can I have gerber data and BOM of the same as I'm not able to identify the component out here.
Kindly reply as soon as possible.
Thank you.
Regards,
Bharat Surani
+91787998867
suranibharat4@gmail.com
Swagatam says
Hello Bharat,
Please click on the diagram to enlarge, you'll able to see the part specs in detail.
I am sorry a gerber file would be difficult from my side.
for more info and BOM you can refer to this original pdf source:
www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CDYQFjAE&url=http%3A%2F%2Fapplication-notes.digchip.com%2F005%2F5-10593.pdf&ei=UTaaVYWdF4uZuQTyvYOwBQ&usg=AFQjCNETxUPxGfwhkqnl61rOFrs0PtJXRw&sig2=t-GcqS0gHIw0fPxqKNz4NA
Anonymous says
Dear Mr. Majumdar, Thanks for the wonderful design. Can you give some information about the filter choke L2 (47mico Henry). How to design it? what is the ferrite core for the same?
SP Arya
Swagatam says
Dear Mr. Arya, it's not so critical, you can make it by winding a reasonably thick magnet wire over any type of ferrite core. Through some trial and error make the number match the shown value approximately….I think about 50 turns using 25SWG wire on any ferrite core would be good enough
AKKU D GR8 says
Mr. Swagatam this thing is looking great for starter's scenario, can you give the detail about each components you have used in this circuit?
Swagatam says
Thanks Mr. Akuu, I'll try to update the required explanation soon….
Rushi Palkar says
sir i have an ic cd6283cs audio amplifier circuit. i give 12v to use this circuit it gets heated up if input is more. and in datasheet it is given that it can handle upto 171v and utput 1500watts. it will be like that? on 12v only it gets heated then how come it will survive on 171v?
Swagatam says
Rushi, the datasheet which you have referred to is of a TAZ (transient absorption zener) not your amplifier IC…..
the datasheet for your IC is probably not available on the net, so can't suggest much about it.
subodh kumar says
I want to make 5 to 12 volt smps work on 60 volt a/c input. may anyone tell me how to make it ?
Swagatam says
you can try the following circuit
https://homemade-circuits.com/2014/03/12v-5-amp-transformerless-battery.html
Pratik Chaphekar says
What should be the changes to make it 12V, 2amp
Swagatam says
make the secondary winding using two wires wound simultaneously…it's also called bifilar winding.
Sharik Baig says
Circuit diagram isn't completely visible, it got clipped from top.
Swagatam says
please check it now.
yasir says
Hi Sir
i want a temperature control circuit for incubator.do u have any circuit diagram.
Swagatam says
Hi Yasir, you can refer to this article:
https://homemade-circuits.com/2011/12/how-to-build-simple-electronic.html
Anonymous says
Hello sir,
this is Pankaj Pandey with another querry ….Sir can you design any 4 way electric chaser circuit by the help of transisters only …because 555 ic is not available now a days .. As I found " two transister based Led switching " in your blog and I also tried by two transister but I am unable to decrease and increase its ON/OFF (switching) timing ..
thanks a lot
P. Pandey
Swagatam says
Hello Pankaj,
555 is an evergreen versatile IC and will be there for at least another 50 years…may be its not available in your area.
Anyway, in your transistor circuit you can add a 100k pot in series with one of the transistor base resistors, this will give you an option for the required adjustments.
hiren kharsani says
hello sir,
From where can i get this type of transformer.
Swagatam says
hello hiren,
you won't get it readymade, you will have to make it with the help of the given date.
Anonymous says
Dear Aseem,
I, better suggest you to do this yourself… and be a good engineer 😉
Aseem Mittal says
Dear Sir,
I am student of B.tech ECE.. I was trying to make SMPS of 150W (of voltage range 60 – 210 Volts DC & about 1 Amp. current). You are kindly requested to guide me for the same & oblige. My main problem is which transformer is to be used & the feedback circuit. I shall really appreciate if you could give me entire circuit.
Thanks & Regards,
Aseem Mittal (09417753155)
aseem.mittal19@gmail.com
Swagatam says
Dear Aseem,
I don't have much idea about the transformer winding details, so I am sorry I won't be able to help with the project.
By the way what is the output voltage of the design?
Anonymous says
Dear Mr. Swagatam,
Thank you for your constant effort. Can I use this circuit for higher current requirement,say 2-3A? If not,please suggest or give a 12V/3A SMPS circuit for driving LED.
Swagatam says
yes you can achieve it by adding additional winding layers connected parallel to the existing secondary layer inside the transformer
Anonymous says
hi sir
i want to know how we can measure that this is 1 amp or 2 amp or 3amp
Swagatam says
by connecting the required current rated load and then measuring the voltage, if the voltage does not drop then it means it is capable of delivering that much current.
agus salim says
Hi, sir
I wanna ask can i use this SMPS circuit in 220V AC ?
Swagatam says
yes you can use it.
shaikh says
sir, a project is given 2 me design a smps wit any values, i m a 2nd year student of ECE, i hav jus entered electronis world, & i donno mch abt smps, can u plz send me a ckt wit an xplanation..
thank u..
Swagatam says
you may refer to the above circuit, and the following link:
https://homemade-circuits.com/2012/03/how-to-understand-switch-mode-power.html
Gulam Halim says
sir can i use transformer from fcl lamp?
Swagatam says
no….
gani saputra says
Dear sir Swagatam. Using ferrite core of cfl is Ok, by removing out all copper wire and then change to the new one as the data showed here as freq nearly same and hole loc Ok.
Swagatam says
Gani, yes you can try it…if the winding comfortably accommodate in the trafo then surely you might succeed in making it work.
tushar kachhadiya says
sir, can i use the above smps in another application??????????????????
Swagatam says
if the load is within the range of the smps then it will work.
Anonymous says
What is the maximum current rating of this PS? Sir, Swagatam Majumdar, can sell your prototype to me? we don't get spare parts here in our remote place.
Swagatam says
It's 1 amp. I am sorry, making the prototype and selling it won't be feasible for me presently.
you may procure a readymade china made smps, they are quite good actually and a lot cheaper.
Anonymous says
dear sir, in smps mobile charge i find a resistor use in ac line before converting to dc line the resistor coding shows red, black, black, gold black or orange black, gold, gold black. all these resistors are with five band gold. can you let me know what its value in oms and ratting. how to red five band coding when we have gold in forth place
Swagatam says
You may use the automatic code calculator given in the below link, just put the colors in the given slots, press "calculate" and your result will be in front of you.
www.hobby-hour.com/electronics/resistorcalculator.php
Anonymous says
swagath sir, 20 oms, i tired to replace the same with a new one and when plugged on it the resistor busted.
Anonymous says
sir, can you let me know how to resolve the above issue
Swagatam says
sorry, I just missed it,
I think there's some other fault in your circuit, otherwise the resistor wouldn't burst.
Does the circuit include an MoV and an NTC at the input???
Anonymous says
it was a ready made charge available in the market. it failed one day, i opened and checked and found the resistor was burned out, used the resistor color code and found it was 20 oms, i replace the same it busted, hence i requested for a clarification
Swagatam says
use a wire-wound type of resistor, rated at 3 watts and check what happens.
Anonymous says
sir can u upload circuit diagram for homemade ups upto 100 watts
haris
Swagatam says
you may check out the following circuit:
https://homemade-circuits.com/2012/02/how-to-make-mini-homemade.html
Anonymous says
thnzx a lot sir 4 ur reply
haris khalil
micaiah says
greeting sir,
what is the size of the transformer to be use
Swagatam says
Hi Micaiah,
Welcome to my blog.
The original datasheet says that the frequency of the above circuit is 60kHz.
I have provided the link of the original website just under the last image, you can check it out there for further details.
Regards
Partha says
Dear Sir,
Greetings, this is Partha, I intend to build the smps by ST as mentioned by you but I have no experience in constructing ferrite transformers. Therefore Sir, may I request for the wire guages that are to be used.
Also what does the figures for the term 'coil' means in the transformer specification sheet?
And at last, what changes need to be made to get 3 separate and isolated output voltages of 12v, 5v, 5v and each of current rating 100mA
Please help me on these Sir
With best regards
Swagatam says
Dear Partha,
Actually i too don't have any experience with winding ferrite transformers, so can't say much about them.
Please click the last figure, you will find all the required details about the transformer.
Best Regards.
micaiah says
hi sir,
this is what i have been waiting for a long time in your hobby circuits. s.m.p.s that you use to say it is too complicated.yes it is, but the answer is not to run from it rather to face it in other to progress.
but sir, i have been making these circuits for a long time changing different i.cs but the fault is always the same frequency not more than 30khz with the lowest ct and rt.pls can you tell me why, or is it because i have been using china i.cs,pls i need your help.thanks and nice to meet you again.
Anonymous says
Sir ,
sorry because I am presenting another query in front of you..sir one of my electrician friend told me that- " Amps = Watts/Volts "…..so according to this formula The max watt which I want not to use is above than 1400 watt and the volts = 220 volt. So required amp= 1400/ 220 = 6.36 amp…I used a 6 AMP MCB but it did not trip even in 2000 watt also…sir Please guide me about it .
Thanks a lot
P.Pandey
Anonymous says
ok sir I want to explain you that why do I need this Knowledge-
Few days before I bought an Induction cooker from the market…the maximum wattage of this cooker is 2000 watt…but I am afraid that this high wattage can damage my house wiring..So I want a suitable MCB or a overlode circuit for it..I used 3 overlode protecter of mixer grinder( 2 AMP each ) in parallel …in 1000 watt lode this protecter tripped after 5 minutes.. than I used a 6 AMP MCB ..but it was tripp after the lode of 2500 watt..Thats Why I am asking you that if you have any idea regarding this or IF YOU CAN DESIGN ANY OVERLOAD CUT-OFF CIRCUIT OF 1200 WATT .
please guide me .
Thanks a lot
P.Pandey
Swagatam says
Hi P Pandey,
Sorry for the late reply, I have noted down your request, I'll try to design the requested circuit, if I succeed I'll posts it here and let you know.
Thanks and Regards
Anonymous says
Hi sir,
This is P Pandey…Sir I am here with another request..Sir have you any idea regarding the power banks for smart phone…I have a smart phone of 2000 mah battery and I want to make a power bank for it…Please give me some ideas / circuits that how can I charge my smartphone ) with the help of a 6 volt 5 AH battery..( it needs 5volt 500 mah charging current )
Thanks
P Pandey
Anonymous says
Hi sir,
This is P Pandey…Sir I am here with another request..Sir have you any idea regarding the power banks for smart phone…I have a smart phone of 2000 mah battery and I want to make a power bank for it…Please give me some ideas / circuits that how can I charge my smartphone ) with the help of a 6 volt 5 AH battery..( it needs 5volt 500 mah charging current )
Thanks
P Pandey
Swagatam says
Hi P Pandey,
You can either connect three 1N5402 diodes in series with the battery and directly connect it with your phone, it will hopefully start charging it.
Alternatively you can just include a 4 ohm, 2 watt resistor in series with the battery positive and connect it directly with the cell phone for initiating charging of the phone.
Anonymous says
sir ,
this is my another query –
I have two inverters 300 watt and 500 watt. so can I get one output of 800 (300+500) watt by running both the inverter at a time .
if possible then plese tell me
Thanks.
pankaj pandey
Anonymous says
Hi sir ,
sir before 1 month I asked about a simple transformer less inverter circuit to you…sir is there any circuit you have designed …if yes please give me the link
Thanks
Pankaj pandey
Anonymous says
sir this information is not available in the vedio ….but i think it may be 50 htz because in this perticular vedio a energy saver cfl and after it a 500 watt drill was working by the help of a very small transformer less inverter and a small ups battery
.
Anonymous says
hi sir ,
some day before i watch a vedio on you tube based on the same topic on
www.youtube.com/watch?v=uHmR6pFI7uA
in this vedio both of the inverter were compared , and according to the performance , and the size the transformer less inverter is looking great .but the input power was same of 12 volt in both cases.
Thanks
pankaj pandey
Anonymous says
hi sir ,
i want to ask you one question that i heard about "transformer less inverter ". so which one is best transformer used inverter or without transformer ? and please give me one simple circuit of Transformer less 500 watt inverter
thanks
Pankaj Pandey
Anonymous says
plz give some idea about the SMPS
Anonymous says
can this switching mode be use in an inverter too?
Anonymous says
Nice one sir,
can we use ordinary transformer for this circuit…? 2.what formulae can be use in other to have other voltages as our output…..regards
Jeran Toledo says
Sir, how to make a pcb layout of dual porarity variable output power supply i want to see a diagram