0-30V Stabilized Power Supply

[Biggy Boy]

Well according to all of the posts in this thread and I have read every single one,
The answer is NO do not use the original schematic! Use the newer one posted in this forums thread.


Glen

 

[audioguru2]

So is it good to make the power supply by the original scheme and parts or not?

1) It does not give 3A at 30V.
2) It has many of its parts overloaded and operating at voltages higher than the max allowed voltage for them.
3) It is not accurate and is not reliable.

 

[seba_031]

Can anyone here, who has made this circuit and it's working properly, send me the part list and PCB layout to my e-mail. And please if it's possible on the one-sided board. Thanks

 

[shoaibasghar]

hello!
i am also thinking about making it as my project for this semester. what i want to know is should i use the info provided in the .rar file by redwire on the first page of this discussion(all the info was updated on 30 dec 09). And does any one have single side PCB layout? If not then could anyone give some tip about making double sided  pcb and how to print redwires circuit from EAGLE(i don't know how to use that software)
also i dont know how you solder things on double PCB. and redwires design (the picture of the finalized circuit) looks on single sided PCB. is it so?

 

[GrahamG]

shoaibasghar - i am busy making the PSU myself. My suggestion, if you have not got the facility to make DSPCB, is to route the board in Eagle on the copper side only and to use top layer tracks as "jumpers". This works well. They must be straight however.

 

[shoaibasghar]

shoaibasghar - i am busy making the PSU myself. My suggestion, if you have not got the facility to make DSPCB, is to route the board in Eagle on the copper side only and to use top layer tracks as "jumpers". This works well. They must be straight however.

u mean to say that i should make only one sided board and connect the upper sides by wires instead?
if so will normal jumper wires do or i have to use thick ones. and which schematics etc are you using? one on first page by redwire?

 

[GrahamG]

u mean to say that i should make only one sided board and connect the upper sides by wires instead?

Exactly.That is how i do it all the time for making prototypes. You just have to remember to keep the top layer "jumpers" straight else you will be soldering in some weird looking wires. If you have to go around a corner then use top-straight, bottom-angled and the top-straight again.

Also remember to make the vias for the top layer with at least a 0.8mm hole size and 1.6mm diameter else you will destroy the via when you drill it.....

if so will normal jumper wires do or i have to use thick ones.

normal UTP core is what I use. Only need heavy duty wire for high current tracks.

and which schematics etc are you using? one on first page by redwire?

I have down loaded the latest, the one with all the RED text. I havn't got much further other than to redo the schematic in Eagle, busy now with routing tracks from the netlist

 

[vacana]

i planning to make a voltmeter and ammeter for this power supply, i will step down the output voltage from the power supply and step up the voltage from the shunt resistor using two opamps configured as differential amplifier.

is the -1.3v from the power supply enough for the meter opamps?

i will use tle2141 for the meter.

 

[Holt]

I have just finished a double sidet pcb using the scematics from redwire, i have modifiet it a little, making the routes and soldering points a little wider to make it a bit more DIY friently, i used the laser print transfer metod from this link http://www.riccibitti.com/pcb/pcb.htm its a bit of a PITA to solder ic-sockets and some of the other components without "eyelet"connector pipes. i have the scematics on a PDF file (front, back and components) but i dont know how to upload them to the site

Holt

 

[GrahamG]

I can' help you here as there seems to be no facility. Perhaps as we are all novice users you cannot do this.

 

[redwire]

GrahamG and Holt

Look below the message block and you will find

>Additional Options...

   
Click on that and you can attach certain files.  Sometimes it will reject certain  formats but if you zip them it is usually not a problem.

 

[Holt]

Thanks redwire, here we go, not quite professional, but i am new to eagle

EDIT: be aware that one of the LED connections are a via point, if you dont mount both LEDs you should solder a piece of wire in the via point

PS-6.pdf

PS-6_bund.pdf

PS-6_top.pdf

 

[GrahamG]

redwire - thanks for the tip. I saw the additional options but didn't open it. I was looking in the icons above the message box.

You presumably have built this PSU. When I eventually get around to routing the PCB and buying the TXs are there any points to look out for ?

I noted in the list of components that some of the specifications are short - i.e. diode bridge should be rated at the full load current and the output driver transistor will probably have to be mounted on a heatsink as the base current to the output TR's will be high (hfe low on these output TR's).

 

[Holt]

When I eventually get around to routing the PCB and buying the TXs are there any points to look out for ?

You should be aware of the footprints of some of the capacitors and the trimpots, i am using an offprint bridge rectifier, because i am going for the 5A version, and i had an 35A rectifier, perhaps a little overkill, but i had it.
i havent finished the psu yet, but should be able to do a test in a couple of days, i am mounting Q2 offprint aswell, i have made the cabinet of aluminium, so i will just mount it at the bottom plate

Holt

 

[GrahamG]

Holt - many thanks for your response. Points are noted. Keep me posted on your developments.

As I said I have not even got around to routing the PCB but I have managed to do the schematic in Eagle 5.0. At least that is a start.

 

[Holt]

Well- i have made a small test, and it seems to work, the only thing not working is RV1 who has no effect at all, not that it matters, the voltage is 0 when turned down, but no adjustment possibel. i have measuret the voltage on pin 1 and pin 5 on U2, and it dosent vary when adjusting RV1.
It seems that the voltage is occilating a bit, but it can be my voltmeter playing tricks on me.
I will put it all together in the cabinet and make some more tests

Holt

 

[audioguru2]

I don't know which opamp you used for U2 and I don't know which schematic you used.
My latest schematic shows the input offset adjustment used for the MC34071 and the TLE2141 opamps:

View attachment 40859

 

[redwire]

GrahamG.    I built the original, and at the least 2 revisions.  I didn't build cases for each but I did temporarily test them with a load.      For the 5A version, I would definately mount the rectifier to the case for maximum heat disipation.  The PCB will work fine just use wires to connect to the holes.  For the on board rectifier, I found some nice heat sinks from some old computer power supplies .  With a small cut along the bottom of the heat sink, it fits nicely on the pcb and works fine for 3A (still gets pretty warm). 

The main thing is to insure your diodes are oriented in the correct direction.  Also a large number of builders connect the BCE terminals on the transistors incorrectly.   

I think the easiest thing would be to convert the double sided Eagle  board to a single.  There will probably be a few jumper wires but it would be easier than ensuring that all vias are found and connected.    That can be done in the autorouting routine.  Of course wire sizes would need to be re-adjusted  but there are only a few that require thicker traces. 

I think most builders have noticed that RV1 does not have much affect.  I believe that C7 bleeds some voltage and the change from a negative -5.6 to -1.3 negative rail may have an effect.      I think you will find that if you have at least some small load the power supply will drop to zero when turned completely down. 

 

[GrahamG]

redwire - thanks fo ryour feedback.

That can be done in the autorouting routine.

I prefer not to auto-route on Eagle as I dont like the way it places tracks. A double sided is fine for me as I just use jumpers for the top layer, adjusting the via diameter for current.

The main thing is to insure your diodes are oriented in the correct direction.  Also a large number of builders connect the BCE terminals on the transistors incorrectly.

 

Noted on your heatsinks and wire sizes, and diode and ECB orientation. I am an electronic engineer and know about this. Overlooked very easily!

I have not checked the circuit out but I hear what you say about RV1. What was it "supposed" to adjust ?

 

[Holt]

I don't know which opamp you used for U2 and I don't know which schematic you used.
My latest schematic shows the input offset adjustment used for the MC34071 and the TLE2141 opamps:

I use the TLE2141, R10 = 1Kohm, trimpot = 5Kohm

Holt