need schematic for switching power supply

linear power supply +charge a sla

hi there, please help me...

please give me a schematic for switching power supply with output 0 V, 12 V, +/- 15 V, and is it possible if in the circuit, i add an ADC circuit to show the output voltage in a seven segment?


thank you very much

troubleshooting a smps

Read there all appnotes concerning "flyback"
**broken link removed**

And read this about ADC with & display **broken link removed**

+sla +charge +1a +efficient +switching

I presume you're looking forward to develop a multiple output switching power supply. You might want to consider providing more specific information. Mind to provide information such as the input for the unit? What stage of efficiency are you looking forward to achieve? Do you intend to use a microcontroller? Have you thought of a method to control the switching frequency?

I will try to help from time to time but I believe many others are way better.

You might want to consider reading up certain materials to exchange ideas in here. Reading materials suggested by IGBT might be able to help you a little to provide ideas in our discussion in future. I've not gone through them, by the way.

switching power supply project schematic

i don't understand because i am not yet read anything about switching power supply, i just know that we can use pulse width modulated sps, and resonant sps, but i don't know the concept, i will try to read it, but i am now currently try to understand more about linear regulator before entering the switching power supply , i want to use the output from the power supply for microcontroller, operational amplifier, comparator, and relay circcuits.

yes, i just try to download the materials that given by IGBT.., thank you very much..

epr29 pcb

about switching power supply:

switch matrix schematic

zhi_yi
Power Integrations provide design software for their TOP inegrated flyback circuits. Just install and enter requirements for your supply.

switching power supply schmatic

Hmm...I was just wondering, Zhi Yi? Are you doing this for self use purposes or its actually somekind of college or university project?

You might want to consider knowing facts in detail before applying if this is a college or university project. Not to say that using a design software to obtain what you need for the circuit is not a good idea. It is actually a good start as well...

Hope to hear updates from you...

devonsc.., yes.., it is for my university project.. we have to use the SMPS for those devices.. can you please give me the schematic? i am not yet understand about SMPS, so, it's difficult for me to design the SMPS thank you..

Hi, not that I'm not willing to help. Don't get me wrong. I no longer using any design simulation program in my PC. Anyway, I will try to help...

As attached is a very-extremely-superb rough guide of a basic DC/DC boost converter diagram. It would be great if you understand this diagram. Note that I'm not calling it a circuit but only a diagram. Do you understand the concept on how this diagram (circuit) works? This is only a basic DC/DC converter which can be easily developed or found on any reading materials. If you started doing feasibility studies for your project, I presume that you've come across such basic DC/DC boost converter.

Frankly, I doubt that there is a way for you to obtain an exact circuit from someone with all the features you want and just apply it. Hence, you might want to consider learning up the basic configuration of the boost DC/DC converter and start to expand/introduce your features bit by bit. In fact, this should be the way to obtain a good grade as well cause you fully understand what you're applying. Right?

Well, I believe many good ones here are willing to guide you through. So, start reading to understand the basics and you will be able to develop fast later, rather than to obtain everything in one piece.

Sorry to say that I couldn't guide you to the right source to read as I really don't have the time to do a google search but I will try to answer your doubts, if any. Power supply is very common topic and I believe your university should books on it.

A few personal questions: Which university are you from? When are you suppose to submit the project? Is this a group work or individual?

Lastly, let me know if you don't understand the concept of the basic DC/DC boost converter. Where is your progress at this moment? Could you give me information on questions I asked in the earlier post? And, hows your progress in reading or understanding linear power supply? It is a great start to first read up about linear power supply, good work! You're in the right track...

yes.. i would like to understand how do my circuit work if i can design the circuit yes, i have some books about power supply, i downloaded it from edaboard, and internet.. but, i can't understand them very well.. i just read a little about smps, and understand a little about it. it said that it is splitted into many topology like buck, boost, flyback, etc, and from all of them, i found that flyback don't need to use choke filter, so i don't need to consider about how to find an appropriate inductor for my choke filter and it said that buck for step down, boost for step up, flyback for dual, the basic is use the output from the rectangular wave that generated, and using the PWM to control the duty cycle, and the transistor/fet will switch on or off (saturate or cut off). and since it's work on saturate and cut off, it will become more efficient, because in the saturate condition, V is low, I is high, so the power will be lower, and in the cut off situation, V is high but I is very low, so it is give more efficient from a smps. buck smps using the catch diode, if the pwm is high, it turned the switch on, the diode will be reverse biased, the output would be go from the choke filter, and if the output from pwm is low, the diode would be forward biased, and the inductor would work as the source, and in dc/dc converter, we can use the transformer to step up or down the output voltage..is it true? Please correct me

for the personal questions, may i reply it to your email ? i can answer it here, but maybe sometime the questions should be replied to your email
i am from Bina Nusantara University, a university in indonesia.. it's a group work, we have to submit the project at the end of december, because we have midtest at november..

quote : Could you give me information on questions I asked in the earlier post?
i am sorry, which questions did you mean ?
yes, i read about linear regulator.. and now i try to learn about smps, there are a lot of topology about smps.. but i see it's basic concept is not far different with the linear regulator, is it true?

thank you very much

Pls. U need give further info. What is the input voltage. Which are the power requirements ( output current for each output ). To find schematics it´s no a problem there are lot of them in the WEB, just visit Power Semiconductor Manufacturers sites and you will get lot of them.

Another question. Do U need also to make a prototype ?

I´ve posted a file "SMPS Links.zip" which could help to get more info. Anyway let me know if we can help U

I almost forgotten that you're trying to buck as well as boost. Frankly, I was once having trouble in developing a flyback.

Sorry not making myself clear, what I meant by my earlier question was as follow:

Mind to provide information such as the input for the unit? What stage of efficiency are you looking forward to achieve? Do you intend to use a microcontroller? Have you thought of a method to control the switching frequency?

Click to expand...

Hmm...is it a must for you to do flyback and obtain the outputs mentioned by you earlier on? Okay, just a suggestion due to the following reasons:

a.) Troubleshooting a SMPS circuit is not going to be easy.
b.) The deadline of this project is near.
c.) You have to prepare a thesis for it as well.

How about changing from flyback to a boost DC/DC converter with features such as overcurrent control, reverse flow control, load protection and so on? In fact, the application for the boost converter can be used to charge batteries in which you can further apply it to manage different equipments. The input can be fed from a AC power supply through transformer + rectifier (or from a solar panel or from both! )

But of course, if you have started developing to a stage, then go ahead with your design, I was just suggesting something which is "simple but not very simple to complete" Oh yea, like omore said: Do you need to develop a prototype? It's always good introduce your project precisely so you can obtain feedback/suggestions from the good ones here.

Yes, you can send me any private messages if you want to.

Anyone out there, correct me if I'm wrong regarding this, I'm trying to learn as well => Yes, you can use a transformer at the output BUT it is not wise doing so. Reason:
a.) Not going to be simple to look for a step-up transformer, not sure about your country.
b.) The efficiency will significantly drop.
c.) If you were to step up the voltage from your output level, you ight only have current in terms of mA.

So:
1.) Consider that suggestion, developing a boost DC/DC converter to charge a SLA battery. You can boost to 12/15V. But one thing, without the -15V.
2) Where is your standings now in this project?
3.) Let us know more about your project about the questions asked earlier on, thanks.

Quote:
Mind to provide information such as the input for the unit? What stage of efficiency are you looking forward to achieve? Do you intend to use a microcontroller? Have you thought of a method to control the switching frequency?

i am sorry, i don't understand about the input for the unit.. should be my answer for this question is the input is the AC current? or.. i need the output from the power supply is +5V, +/-15V, and +12V, and about the current, i am not sure.. they just told me to use 5A step down transformer.. of course i want the high efficiency.. yes, in this project, they will use microcontroller.. i haven't thought any method to control the switching frequency..

actually, it is not important whether i use linear regulator or use switching mode power supply, they didn't tell me to use the SMPS, but i want to learn the concept of the smps, and since it has more efficiency than linear regulator, so, i prefer smps to linear regulator, but i am not yet choose the topology for the power supply..

why the boost can be use to charge the batteries?? how about the buck?? and how about the flyback??

sorry.. what is the meaning of prototype ?

yes, it's not easy to find the inductor or the step up transformer in my country, and because of that i choose the flyback because it don't need choke filter, but i don't mind that flyback is more complex than the boost/buck.. if i use the transformer, why the efficiency will be significantly drop?

i heard that inductor is the source of noise, is it true? if it is true, what is the reason that inductor is the source of noise?

in this project, i just called to build the power supply the less is the responsibility of my senior.. i just know that in this simple project, we want to build a security for a class room, in the class would be have light/lamp, air conditioner, and projector, so, we want to do such smart building, the light/lamp and the air conditioner will be on or off if there is a class or not, so it is controlled with microcontroller and relay circuits, and they said that there would be a network microcontroller to link all of them to the PC, and it would be controlled by PC, and then they will build some sensor to detect if someone try to steal the projector, if someone is trying to steal the projector, the circuit will send signal to the µC in that class room, so there would need a schmitt trigger, and then the µC in the room will send information to the PC.. please help me, is there any better suggestion for this project?

thank you very much

In order to be able to give U an schematick for the PS there are some info that U must bring. If U do not know, U must find out.
1 ) Input voltage ( AC also line freq. )
2 ) Current rate for each output.

I´ve just made an offline SMPS ( flyback TOPOLOGY ) With the following basic specs

Vin: 220 ACV +20 % -25%

Vo1: 5VCC 1A
Vo2: 12VCC .9A
Vo3: -12VCC .5A
I can bring U detailed info of it. Also I can give U an schematics for the outputs U need but need to know what I asked for above.
Someone suggest U not to start with a flyback topology, and she/he is correct because if U are going to construct the power supply U will spend a lot of time the first time. The construction of the flyback inductor ( transformer ) is not easy.

Added after 4 minutes:

Another little help ( Hope )

Visit www.powerint.com There U will find schematics of SMPS with characteristics close what U are looking for. Also see thei Engineering reports in which u also will find PCB layouts

Hi,

a.) Mind to provide information such as the input for the unit?
=> I believe omore has explained this...

b.) What stage of efficiency are you looking forward to achieve?
=> It depends. There times where we can work from the back to obtain a rough guide of what efficiency we would love to achieve. As the efficiency will indirectly determine our selection of switching frequency in which affects the selection of inductor and capacitor that we need. But it is okay, forget about this point.

c.) Do you intend to use a microcontroller?
=> You told me that you intend to use a microcontroller to control this. A trick question here: Do you really need a microcontroller to control the PWM signal as well as 7 segment LED? Why or what makes you think that a microcontroller suits/is a better choice for your application? Just get yourself prepared for such questions being thrown by your lecturers. Well, I never touch ATMEL MCU, but I will try to help if you're using PIC. Have you finalized what microcontroller to use?

but i am not yet choose the topology for the power supply..

Click to expand...

Do you intend to make a change? If yes, make it fast. Decide on the next post. As omore said, its not easy at all to develop a SMPS circuitry. Theoritically, its simple but you might have lots to troubleshoot when you implement it practically.

sorry.. what is the meaning of prototype ?

Click to expand...

Prototype means, building it for real. Meaning, you need to build the power supply unit that you have designed and not just submitting your simulated design.

why the boost can be use to charge the batteries?? how about the buck?? and how about the flyback??

Click to expand...

No, I think you got me wrong. I was just trying to make a general statement: Boost easier as compare to any others. Note that no books will mention this, this is not a point. To me, it seems that it is slightly easier to boost as compare to any other SMPS circuitry, correct me if Im wrong, omore. And I suggest you to seriously consider boost DC/DC converter and introduce a SLA battery in your project in order for you to finish by end of December. What do you think of this? => Implementing a boost DC/DC converter with the input from either 240V AC or solar panel. Meaning, the circuit will be "alive" at all times having it to auto-switch the input from 240V AC to solar panel and vice versa. If the panel receive a sufficient amount of power, the circuit will be powered up by the solar panel else it will switch to the 240V AC. The circuit will be "alive" at all times to charge, for example a 12V SLA battery. Which is enough for you to trigger your alarm, I think.

There is a lot of ambiguity in your post where I believe it stops people from knowing exactly what you're trying to do. You were saying that this particular circuit is meant to trigger alarm when someone is trying to steal. Something very simple that you didnt consider here. What if someone cuts the power line, does it mean that he/she is now FREE to take what he/she wants?? You get me?? With the 12V SLA battery, you can still trigger the alarm? Right???

Based on your other posts in other forums and here, it seems that you have yet to finalized everything. Maybe you have to finalized something to stick to it.

I´ve have just sent U a zipped file with some apps notes, schematics and PCB layouts. Hope this help U.

Anyway. consider what devonsc says, he is right from my point of view.

sorry for the late reply.. thank you all

quote :
In order to be able to give U an schematic for the PS there are some info that U must bring. If U do not know, U must find out.
1 ) Input voltage ( AC also line freq. ) => 220 ACV (sorry, what is +20% - 25%??)
2 ) Current rate for each output. => i need Vout = +5V,+/-15V,and +12V (1A)

Visit www.powerint.com
=> I've visitted this site and try to find the schematic match for my PS, but i find none of the schematic there match with the output i needed..

quote:
You told me that you intend to use a microcontroller to control this. A trick question here: Do you really need a microcontroller to control the PWM signal as well as 7 segment LED? Why or what makes you think that a microcontroller suits/is a better choice for your application? Just get yourself prepared for such questions being thrown by your lecturers. Well, I never touch ATMEL MCU, but I will try to help if you're using PIC. Have you finalized what microcontroller to use?
=>oo.. okay thank you, i haven't finalized what micrcontroller to use.., but is it we need to use the MCU to control the PWM in this SMPS?

quote:
Do you intend to make a change? If yes, make it fast. Decide on the next post. As omore said, its not easy at all to develop a SMPS circuitry. Theoritically, its simple but you might have lots to troubleshoot when you implement it practically.
=>still i want to develop a SMPS circuitry please choose an appropriate topology for me, for a beginner to understand the SMPS, it must be boost dc/dc converter, right?

quote:
Prototype means, building it for real. Meaning, you need to build the power supply unit that you have designed and not just submitting your simulated design.
=>yes, i want to build the power supply unit..

quote:
There is a lot of ambiguity in your post where I believe it stops people from knowing exactly what you're trying to do. You were saying that this particular circuit is meant to trigger alarm when someone is trying to steal. Something very simple that you didnt consider here. What if someone cuts the power line, does it mean that he/she is now FREE to take what he/she wants?? You get me?? With the 12V SLA battery, you can still trigger the alarm? Right???
=>yes i get the it, so.. i need a 12V SLA battery, and.. sorry, i don't know.. what is the meaning of SLA??

so.. i would need to build a boost DC/DC converter with the input from either 220V AC or solar panel. Meaning, the circuit will be alive at all times having it to auto-switch the input from 220V AC to solar panel and vice versa. and i don't understand what is a solar panel.. and never see the solar panel..

quote:
I´ve have just sent U a zipped file with some apps notes, schematics and PCB layouts. Hope this help U
=>thank you very much omore.. but i am sorry, where did you send the zipped file?? which one is it?

thank you very much

1 ) Input voltage ( AC also line freq. ) => 220 ACV (sorry, what is +20% - 25%??)

Click to expand...

I'm not quite sure about this, maybe omore can help you out with this. Could it be the tolerance of 220V AC? But the amount of variation seems to be real high. Maybe it is like that in your country...

2 ) Current rate for each output. => i need Vout = +5V,+/-15V,and +12V (1A)

Click to expand...

Why do you need such output if you were to only trigger alarm? I believe you only need one specific output for that particular alarm circuit. Please clarify this...

Visit www.powerint.com
=> I've visitted this site and try to find the schematic match for my PS, but i find none of the schematic there match with the output i needed..

Click to expand...

The right thing to do is to understand and learn the basic boost DC/DC converter and expand your entire project from there by designing it yourself. In that way, there is no plagiarism involve and you know everything at the back of your hand. This helps you when you need to do explanation to your lecturer. Searching for the exact circuit you want might be a waste of time, you might really want to consider reading up and asking the pros here on what you don't understand. Time is runnintg out.

=>oo.. okay thank you, i haven't finalized what micrcontroller to use.., but is it we need to use the MCU to control the PWM in this SMPS?

Click to expand...

If you're only using 7-segment LED display, is it a must for you to use MCU? I believe there are 7-segment LED drivers available in the market. Controlling the PWM signal using a MCU is one of the method that can be applied. Note that you can actually use 555 timer as well, but it consumes more power (and less efficient, I think). These are the points that you should really consider while doing your project to answer questions thrown by your lecturer.

=>still i want to develop a SMPS circuitry Smile please choose an appropriate topology for me, for a beginner to understand the SMPS, it must be boost dc/dc converter, right?

Click to expand...

No, its definitely not a must. I'm just suggesting you to implement boost. I can't find any reason for you to use a flyback here as you only need to trigger your alarm circuit.

=>yes i get the it, so.. i need a 12V SLA battery, and.. sorry, i don't know.. what is the meaning of SLA??

Click to expand...

Sorry, I should write this in full, SLA means Sealed Lead Acid Battery...

so.. i would need to build a boost DC/DC converter with the input from either 220V AC or solar panel. Meaning, the circuit will be alive at all times having it to auto-switch the input from 220V AC to solar panel and vice versa. and i don't understand what is a solar panel.. and never see the solar panel.. Sad

Click to expand...

It's okay, forget about solar panel, its not going to be cheap anyway but in your thesis you might want to write this point as a future consideration to further improve the design.

Hope to hear from you regarding your progress at the next post.

quote :
In order to be able to give U an schematic for the PS there are some info that U must bring. If U do not know, U must find out.
1 ) Input voltage ( AC also line freq. ) => 220 ACV (sorry, what is +20% - 25%??)
+20% -25% is the line voltage tolerance. In the SMPS I did it was needed due to the fact that my customer asked for that. This tolerance is not difficult to achieve for an off line SMPS ( Off Line state for a SMPS that is powered from the AC line

2 ) Current rate for each output. => i need Vout = +5V,+/-15V,and +12V (1A)

So the total Power is abt 50W

Visit www.powerint.com
=> I've visitted this site and try to find the schematic match for my PS, but i find none of the schematic there match with the output i needed..

Look for: di16.pdf di30.pdf di33.pdf di39.pdf di41.pdf epr13.pdf epr29.pdf

This documents will be a good guide to what U need.


quote:
You told me that you intend to use a microcontroller to control this. A trick question here: Do you really need a microcontroller to control the PWM signal as well as 7 segment LED? Why or what makes you think that a microcontroller suits/is a better choice for your application? Just get yourself prepared for such questions being thrown by your lecturers. Well, I never touch ATMEL MCU, but I will try to help if you're using PIC. Have you finalized what microcontroller to use?
=>oo.. okay thank you, i haven't finalized what micrcontroller to use.., but is it we need to use the MCU to control the PWM in this SMPS?

Discard the idea of using a uController for the SMPS

quote:
Prototype means, building it for real. Meaning, you need to build the power supply unit that you have designed and not just submitting your simulated design.
=>yes, i want to build the power supply unit..

Well ... herry up, guess U are short of time....

quote:
There is a lot of ambiguity in your post where I believe it stops people from knowing exactly what you're trying to do.......

As devonc says, tha´s my feeling


quote:
I´ve have just sent U a zipped file with some apps notes, schematics and PCB layouts. Hope this help U
=>thank you very much omore.. but i am sorry, where did you send the zipped file?? which one is it?

I sent it to xwcwc1234@yahoo.com.tw isn´t it your email. I´ve received an emails asking for them. Anyway this file contains the pdf files I mentioned above.

quote:
Why do you need such output if you were to only trigger alarm? I believe you only need one specific output for that particular alarm circuit. Please clarify this...

=> i need those output not only for trigger the alarm, but also for the microcontroller (Vcc&Gnd), for Op-Amp (+/-15V), for Relay circuit (+12V), is it right? please correct me..

=> okay.. i will try to understand the application notes and also the example design in the www.powerint.com.. i've download the pdf but not yet read it.. because i have to prepare for my mid test too.. i will try to understand it first.. thank you..

quote:
Discard the idea of using a uController for the SMPS

=>why should discard the idea of using uC for SMPS? if using the uC for the SMPS, where to use it? i just know a little that in SMPS we need rectangular wave, PWM controller, switching transistor/fet, is it right?

quote:
I sent it to xwcwc1234(at)yahoo.com.tw isn´t it your email. I´ve received an emails asking for them. Anyway this file contains the pdf files I mentioned above.

=> no.. it's not my email address.. my email address is "leon_baida@yahoo.com", can you please send it once again to me.. thank you very much

- how to know how much is the tolerance from the AC voltage?
- what is a Sealed Lead Acid Battery? what is the function of a sealed lead acid battery?

thank you very much for all the helps..