Power supplies

[Wizpic]

I did sometime ago build the Velleman power supply but it's getting old now and battered and the ouput is now stuck at 16V can't be bothered to investigate it has it has been reapired a few times (from abuse off me). Plus velleman dicontinued it long time ago.
So I'm looking for a good design of a new power supply anybody recommend one.
For long time now I'v been thinking of a digitally controlled power supply but the designs I've have been no good or unstable output.

any links or info or ideas would be good

[gopi_sonsivri]

can u xplain more clear i mean power supply for wat freq, , ac. or dc

wat kind of load u have?

[Wizpic]

I want to build a 0-30V 0-5amps power supply for the workshop , But the ones I've sen do not look that good

I suppose that would of helped

[MAXPAYNE]

There is a very popular and effective project in Electronics-lab. But it is linear in nature. U may try it ........... also check their forum for discussions and modifications.................

http://www.electronics-lab.com/projects/power/003/index.html

and for the modifications

http://www.electronics-lab.com/forum/index.php?topic=19066.0

[tAhm1D]

Hi,
If you're interested in building a switching power supply, you can try flyback, and if you're going in that direction, have a look at the circuits provided in the power int website:
www.powerint.com

[Wizpic]

There is a very popular and effective project in Electronics-lab. But it is linear in nature. U may try it ........... also check their forum for discussions and modifications.................

http://www.electronics-lab.com/projects/power/003/index.html

and for the modifications

http://www.electronics-lab.com/forum/index.php?topic=19066.0

I did come accross that one but did not know if it was worth building it, Has reading the topic about this power supply the older one has many errors on it, but the newer design has fixed the errors.
Thanks Tahm but I would not prefer to cuild switch mode. Might consisder in building another velleman PSU has I have all the files all ready. Not usre yet 

[MAXPAYNE]

I did come accross that one but did not know if it was worth building it, Has reading the topic about this power supply the older one has many errors on it, but the newer design has fixed the errors.
Thanks Tahm but I would not prefer to cuild switch mode. Might consisder in building another velleman PSU has I have all the files all ready. Not usre yet 

I have built it and using it and abt performance, what i can say is awsome............:-)

[Wizpic]

After doing some more research om power supplies and looked at 100's of designs and after giving it some seroius thought I now know which type amd which one I'm going to design and build. It will be 0-30V 0-5A/10A (hopefully dual one.  )

I've always liked the idea of push buttons to adjust the voltage/current so I have gone for doing it this way, I have setup the power side and this is all working very good by controlling it with pot's, The next stage is to get it hooked up to my dev board and see how accurate it is at controlling the voltage and current and go through all the ranges of voltages to make sure it will be good enough.

Has for the display I was thinking of using 8 x seven segment for the voltage/current Or a LCD/GLCD so that you can set the max voltage/current limit so you don't over shoot amd blow your new project up Or use both LED'S and a LCD to do the same but just have the LCD to display max voltage/current, I will have to give this some more thought, I was also considering to have some fixed outputs of +/-5V and 3.3V

I will give you updates how I'm progressing with it all.
How would you guys think of displaying the data if you was doing it, Throw some ideas at me about it and anything else that you think would be good to have in a power supply

 

[Wizpic]

After a day of testing I'm not happy with it the output voltage is stable but not accurate enough for my likings, Even though the voltage coming out of the pic is steping up in MV like 0.01,0.02-----------1.21,1.22,1.23 or on the coarse it step up in 0.1v steps, So I now know that I cannot use the hardware I have got set up of to look at other designs now

[tasosstr]

After doing some more research om power supplies and looked at 100's of designs and after giving it some seroius thought I now know which type amd which one I'm going to design and build. It will be 0-30V 0-5A/10A (hopefully dual one.  )

I've always liked the idea of push buttons to adjust the voltage/current so I have gone for doing it this way, I have setup the power side and this is all working very good by controlling it with pot's, The next stage is to get it hooked up to my dev board and see how accurate it is at controlling the voltage and current and go through all the ranges of voltages to make sure it will be good enough.

Has for the display I was thinking of using 8 x seven segment for the voltage/current Or a LCD/GLCD so that you can set the max voltage/current limit so you don't over shoot amd blow your new project up Or use both LED'S and a LCD to do the same but just have the LCD to display max voltage/current, I will have to give this some more thought, I was also considering to have some fixed outputs of +/-5V and 3.3V

I will give you updates how I'm progressing with it all.
How would you guys think of displaying the data if you was doing it, Throw some ideas at me about it and anything else that you think would be good to have in a power supply

 

Hello Wizpic,

What i would like to have it is a Dual Power supply with two GLCD with Touch screen one per Power module, two emergency buttons, one per unit and why not a third display LCD or GLCD for monitor all the time the Voltage and the current of each channel, so even if i have boot in menu for the one channel still i can see what doe's the output :-)

Plus a temperature display on the third screen and turn off the output if the temperature is too high.

That's for now if i will thing something more then i will come back to you :-)


Good luck and have fun ;-)

[picaboo]

Hello Wizpic,

Have you decided to build it yourself for kicks? Or do you want to buy one if affordable?

My experience is that I generally buy stuff which is not related to my core research or project. For me power supply is a serious issue for any project and if I am not a expert in it, I always leave it to the expert and buy reputed product so that I can focus on my project. Otherwise I will be spending money, and more precious time on the power supply design, which has been anyway perfected by experts. And I do not mind investing on it because of its importance in a project. Same goes for any measurement instrument (for eaxmple, storage oscilloscope).

I am from India and 0-30V, 2A bench-top power supply with digital 7-seg display is available for Rs.2000 (USD 40). I use it for all my PIC project and peripheral development.

Just my 2 cents.
--picaboo

[tasosstr]

0-30V, 2A bench-top power supply with digital 7-seg display is available for Rs.2000 (USD 40)

It is new or used ? Any link so and us we can buy ?

[waicon]

couple of weeks ago, i've finished built a adj. HV powersupply due to my project required,  have been use it for 1 week, well nothing bad happen or blow up anything. i think u can try it, it is stable ; simple . Voltage adj from 0~67VDC at 125Watt, and ofcouse with current limit at 0.7A~4A. but somthing i did not happly about it, is b'cos it is not digital adj , and some not return to zero when totally turn off (tune to min voltage), still some 0.7V there.

http://rapidshare.com/files/327511680/hv_powersupply.rar

well , overall is good design, i think.
 

[Wizpic]

I shall have a look at the power supply,
Tasosstr long time no ear, hope your good, I want to build a power supply so if I blow it up I can repair it 

It's cheaper and more fun to build your own

[waicon]

it is fun to have own built PS . remain 0.7V min, could be R7 or D3 value, i tested using remove Q1, it is not ICEO from Q3. still no ideal how to fix it  , b'cos this design only 1 month old  ... i'm bz on how to make it with 7seg@3digi voltage/current display using 16F688. maybe in furture i'll make it digital conrol if i've time.

[tasosstr]

I shall have a look at the power supply,
Tasosstr long time no ear, hope your good, I want to build a power supply so if I blow it up I can repair it  

It's cheaper and more fun to build your own

Hello Wizpic

Yeah really a long long time, i am fine, than you :-) i hope and you to be ok :-)

I was very busy with the works so ....

I agree about the Power supply, You can fix it easy and for sure and you can add more future later to this without huge cost :-)

And when all finish you are very happy :-)

You must first design and finish the hardware and then play with the software :-)

Have Fun :-)

[Wizpic]

Power supply update, I've been watching a topic on the electronics labs about the new power supply design.
0-30V 0-5A using mosfet's, So i decided to have a look and start to play with it and share the desing here for you to have a play around with i and get your views.
A WORD OF CAUTION THIS IS NOT A FULLY WORKING PSU IT'S STILL UNDER DEVELOPMENT

What I mean it's not fully working I've only simulated it in ISIS and so far the results show very good results you can fully vary the voltage and amps and the current limit works really well. The only difference is that there should be a mosfet to to switch between he low voltage and the high voltage but I could not get this to work ISIS.(Not fully looked into why not yet) I used a relay instead, Some of the part numbers/values may not be correct and may need tweeking in real life, I'm yet to get this built up and and tested to see how the PSU preforms in real time.

Things to be added if it works well under test constant voltage/current LED'S, Current limiting LED and may be digtial control as well, Over the next few weeks I shall try and get one built up and run various test's on it. I have a load tester and I can give it a could bench testing to see how how hot the FEt's get or how long before it blows up

[rmb1099]

... Things to be added if it works well under test constant voltage/current LED'S, Current limiting LED and may be digtial control as well, Over the next few weeks I shall try and get one built up and run various test's on it. I have a load tester and I can give it a could bench testing to see how how hot the FEt's get or how long before it blows up

I'm interesting to your results, when the first test it down?
By acceptable result, I will build one also.

[waicon]

little help on display, another update for this, i've completed the PCB design(altium summer09) for LCD display, fo those don't have PCB viewer, schematic look in pdf instead. it is a complete with PCB, design schematic..etc.
 
http://depositfiles.com/files/1r49txqrt

measure VOLT is resistors divider, measure CURRENT at high site of supply not direct, it measure shunt resistor V, it is I/V convert using differential op-amp. have made some PCBs, writing program to test out.
 

[Wizpic]

measure VOLT is resistors divider, measure CURRENT at high site of supply not direct, it measure shunt resistor V, it is I/V convert using differential op-amp. have made some PCBs, writing program to test out.
 

looks nice and simple good work
Looking at your schematic I'd be really careful with it if your using ICSP part, You need to add a diode before R13 that goes to Vcc, or after R13 but before the ICSP pin1 this will prevent from 13Volt going into your VCC supply, This could damge the PIC and LCD has they only run from 5V.

I will keep you informed on any progess or updates

Posted on: February 08, 2010, 09:27:44 21:27 - Automerged
This is my meter I was considering to add to the PSU. Then may be a LCD to display other stuff or just use a GLCD to display all of the stuff instead of LED'S, But I like just the LED'S idea has there bigger and brighrter and more easily to see.

I've only simulated it with a 0-5V (0-48V input from the PSU) and 0-1.5V(0-5amps). I've not added the resistor divider or the booster curcuit. I know this works well has I already have it in another PSU working, The hex included is only a sample and may not be accurate.

[waicon]

oop!! over look the VPP site 

Posted on: February 09, 2010, 08:29:07 20:29 - Automerged
DSN files using which software to open ? i must be out-dated.

Posted on: February 09, 2010, 08:32:58 20:32 - Automerged
7 seg display, it remind me another PCB design half way stop due to have hard time on programming on sharing mux S3;4 with RS232 signal, and no VI converter. not user friendly. especialy if want to measure current on high site power line.
http://rapidshare.com/files/348158360/7seg-voltmeter.rar 

[zorx]

It appears that attached *.DSN file is "ISIS Schematic Capture" file from Proteus.

[oldvan]

Looking at your schematic I'd be really careful with it if your using ICSP part, You need to add a diode before R13 that goes to Vcc, or after R13 but before the ICSP pin1 this will prevent from 13Volt going into your VCC supply, This could damge the PIC and LCD has they only run from 5V.

I see this advice given often, and I wondered:

Is a diode in series with the VPP pull-up resistor necessary?

I notice that Microchip does not use a diode in that position, but am not inclined to believe that they are infallible, so thought through WHY or WHY NOT to include the diode.

Microchip simply uses a 10K pull-up resistor from VPP to VCC. (VDD is VCC with a different choice of name)

From the schematic for Microchips’ CTMU Evaluation board:
     

A 10K resistor with 8V drop (13V on one end, 5V on other) will provide V/R = 8/10,000 = 0.8 ma to VCC during programming.  A 3V VCC would increase this to 1 ma.

As long as the circuit draws more than 1 ma, programming voltage's influence into VCC will only lighten the current through the VCC regulator and VCC will not rise.

With the circuit provided, the 1K LCD contrast pot from VCC to GND draws 5 ma, so the circuit will always have at least a 5ma draw.  The PIC, LCD and op amp also draw current, of course.

There may be special circumstances that require the diode, such as some homebrew programmers (including the first one I built) which are not be able to correctly source the extra ma of VPP.

The bottom line is there is no need for the diode here, and OK to leave it out as Microchip does. 

[EDIT:  TYPOS]

[waicon]

ok, R13 change to 10k.

[Wizpic]

DSN files using which software to open ? i must be out-dated

Yes sorry I can  upload PDF of it but you would just be looking at the schematic where has is Proteus ISIS you can simulate it has if it was in real life, This way you can do 99.5% of debuging and a complete working project with out building it