24V to 5V dc to dc converter

[king]

Hi!
  I need 24V to 5V DC to DC converter schematic or related document.If better then give me some idea that how can I convert 24v dc into 5v dc with the help of PWM. If you have any schematic or document related to this then please share it.
Any kind of help will be highly appreciated.

Regards

King

[petarp]

Hi. You can look here:
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2590&param=en528255
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en540057
This is Microchip's MCU designs for buck converter.

Best Regards.

[Roshan]

use lm2576, it is best option. Capable for 3 amp.

[alien]

In my opinion IC MC34063A buck/boost switching regulator will be a better solution...try googling MC34063A and you will find many links for datasheet,application notes etc.......and here you will find a web browser based design tool to make life easy http://www.nomad.ee/micros/mc34063a/index.shtml

[titi]

Hello,

I used LM2575 - SIMPLE SWITCHER 1A Step-Down Voltage Regulator
Very few compoments, low cost.

http://www.national.com/mpf/LM/LM2575.html



larger image:
http://www.national.com/images/pf/LM2575/1147501.pdf

Datasheet:
http://www.national.com/ds/LM/LM1575.pdf


Best Regards.

[poweralgorithm]

How much current do you need ?

[free]

You can visit linear website, www.linear.com on power management.

[Wragie]

Another one you can use is the TI TPS family. 1-6 amps and up to 60 volts.
 Look for the TPS54620 it should list 5 or 6 modles that vary in voltage and amps.
You should be able to sample them as well or buy them for about $17 from Newark.

www.ti.com

W

[king]

Hi!
   But i want to make it by myself using PWM technology in higher current ratings.

Can anybody has an idea of how to make DC to Dc converter using PWM then please tell me.

Regards

King

[oldvan]

If I were anxious to roll my own design of switching converter like this, I'd likely get pretty carried away.   DSPIC chip, LCD display, nice enclosure, etc.  Would be cool to be able to display current output, efficiency, total run time, etc.

With ready-made solutions available off the shelf, I'd be more inclined to buy the solution and spend my time on something else.

[Wizpic]

Hi!
   But i want to make it by myself using PWM technology in higher current ratings.

Can anybody has an idea of how to make DC to Dc converter using PWM then please tell me.

Regards

King

There is just a bit more to it than that, the way I would do it is use the 10bit PWM read the voltage and current back then adjsut the PWM accordingly, If you draw to much current then shut it down, But if you look inside a switch mode power supply or a dc to dc converter you will see how much stuff there is in there, Same thing again search and you will find some book on it,

If I were anxious to roll my own design of switching converter like this, I'd likely get pretty carried away.   DSPIC chip, LCD display, nice enclosure, etc.  Would be cool to be able to display current output, efficiency, total run time, etc.

With ready-made solutions available off the shelf, I'd be more inclined to buy the solution and spend my time on something else.

I would attend to agree with you but rolling your own design does give you good satisfaction at the end of itand the bonus to it if it break you could repair it, But like you said in this case I would just buy one has there is lots to DC to DC converters, I have thought about having ago at my own tried a simple one but blew it up    , when  I got to 10amps so I gave up on the idea and went and brought one that gives me the 15amps required form time to time but this was 24V to 12V and it did not cost that much compared to the time spent and parts cost of it,

wizpic

[king]

Hi!
   I am completely agreed with both of your ideas but my job is related to R & D if i am going to buy each and every item from the market they i want to know where i am standing and what are my skills? let suppose this time i need 24v to 5V Dc to Dc converter and next time i need 15V to 3.3V DC to Dc converter and again next time i need 10.5V to 3.5V Dc to Dc converter then what i have to do, again buy it item from the market? that is not the solution of the problem and if i got success in making any one of them then i will definitely make all of them & "That's the Point My Friend".Actually i need various kind of power supplies whose input and output voltages are different every time that's why i want to developed it, in order to close this chapter for Ever.

And i have find microchip application notes in which they describe about buck converter and they are very useful in making them and i will sooner upload them so all will get help from them.

regards

King

[oldvan]

I would suggest it takes a noteworthy measure of skill to source the correct IC, inductor, diode, etc. to meet a particular need.  It takes additional skill to correctly mate those components on a circuit board that fits the available area and provides the needed connections, etc.

DC-DC conversion is an old and common need in electronics; the needs you mentioned are not at all unusual.  Many of the chips available for the job offer adjustable output voltage, adjustable current limiting, etc. and can be used for differing needs.

Maxim, TI, National Semiconductor, and so on have thousands of engineers in their employ and hundreds of thousands or more man hours of experience with these things, so I'd gather you will be facing a near impossible challenge to equal or surpass their offerings.  Overall the readymade DC-DC converter IC will be less expensive, more reliable, more efficient, less prone to generating interference, and more feature rich than one you can make on your own.  This is the very reason the companies offering the ICs stay in business.

Circuit board layout for a successful DC-DC converter that behaves correctly across a wide range of loads, doesn’t generate huge amounts of needless RFI, etc. is not a trivial task.  Adding microcontroller programming, current sense circuitry and so on to the task needlessly adds orders of magnitude more complication.

Based on a lifetime of experience, and please take this as it is offered (kindly advice from a friend who cares):  I suspect your employer will not keep for long one who is expert at needlessly reinventing the wheel, especially if it comes at increased cost to the company and their customers.  The most important thing your skills can ever bring your employer is success.

[king]

Thanks for the answer but i am belonging to Pakistan and in Pakistan we will not get "Maxim" or "TI" or IR (International Rectifier)" IC's easily available, they are not commonly available in our market and our many works are pending due to non availabilities of these IC's so that's why i am in favor of developing those things which are in my range and not easily available in the market. For an instance my boss has assigned me the project of 3-Phase induction motor control and for this i need IR2104 or IR2109 both are not available in the market so i have import them then for this also i need the PIC Micro controller (PIC 16F777)which has three PWM Modules and again it is not available in the market so i have import them  so this is the reason of developing those things, the components which are available in the market i will definitely buy them and put them on my PCB directly but that are not available then what to do? And if i import components then they will become too much costly for my design as well as cost of the circuit increases too much.

Regards

King

[oldvan]

WOW!  An entirely different and most difficult situation!  I forget that I live in a very much spoiled country where I can have most any IC or transistor I need in hand within a couple of days and for reasonable price.  You face many more challenges than I was previously aware!

Is there a reasonable way someone like me, situated in America, could help to make things easier for you acquiring components you require?

John

[tAhm1D]

Hi king,
Here I post a circuit for converting 24vdc to 5vdc. The circuit uses L4960 from ST Microelectronics and can give a maximum current of 2.5A. If you need higher currents, there are more ICs: L4970 is 10A max, L4964 is 4A max,etc.
I used this circuit and it is reliable and cheap as here in Bangladesh an L4960 is $0.40 each.

[qolpa]

hi,

if it is in your market you can build a circuit with 3842 or 3843 PWM IC. but the circuit will not be a cost-effictive if you need small currents because of the other elements like mosfet.

regards