I believe the intent was to "monitor both sides", but I agree with you - the zener voltages need to be changed accordingly.
Hi wine&dine, thank you, thought of that trick too, just wanted to make sure. What i'm not sure is: is still connected the same way the 310V and float points? Right now I'm reading the Marty Brown book (power supply cookbook), and will begin to calculate for my needs.
How about the feedback network? It's necessary to track both sides or just one of them?
Still reading...
Luigi
How about the feedback network? It's necessary to track both sides or just one of them?
Still reading...
Luigi
PCB for SMPS +/-50V
Hi folks.
Another PCB variant http://freepdfhosting.com/3bb9b920ad.pdf not tested , but I hope to be good all the best alex mm
Hi folks.
Another PCB variant
http://freepdfhosting.com/3bb9b920ad.pdf not tested , but I hope to be good all the best alex mm
Very nice! A SMPS for audio amps!
Unfortunately I don't have much understandings of a SMPS, but I'm interested in using one for a power amp.
Looking at the schematic I've the impression that one would just need to change the windings ratio on the transformer connecting the switching part to the outside world (the ETD59 core).
And as always I'm sure it's not as easy as that, so it would be great if somebody could point me to information about doing that - say I'm interested in +/- 25V rails?
By the way, what's the max output current of that SMPS?
Have fun, Hannes
PS: yes I'm scared by lethal voltages.
Unfortunately I don't have much understandings of a SMPS, but I'm interested in using one for a power amp.
Looking at the schematic I've the impression that one would just need to change the windings ratio on the transformer connecting the switching part to the outside world (the ETD59 core).
And as always I'm sure it's not as easy as that, so it would be great if somebody could point me to information about doing that - say I'm interested in +/- 25V rails?
By the way, what's the max output current of that SMPS?
Have fun, Hannes
PS: yes I'm scared by lethal voltages.
10 A peak would be nice; of course I would use a regulator after the SMPS which can handle 8A.
The reason for the low rails (+/-25V) is the balanced topology, so in fact the speaker sees +/- 50 V maximum.
Have fun, Hannes
By the way, Ljubljana is a very nice city! Been there often, especially in Krizanke.
The reason for the low rails (+/-25V) is the balanced topology, so in fact the speaker sees +/- 50 V maximum.
Have fun, Hannes
By the way, Ljubljana is a very nice city! Been there often, especially in Krizanke.
Hi
You don't need regulators, as you can make it regulated suppy..I think it can do this, probably first liniting component is too small trafo, but you should have problems with that. Other is somewhat correct winding of trafo...anything else is easy, really easy. Chech my site to get some idea what to expect or need, maybe you will find something useful
You don't need regulators, as you can make it regulated suppy..I think it can do this, probably first liniting component is too small trafo, but you should have problems with that. Other is somewhat correct winding of trafo...anything else is easy, really easy. Chech my site to get some idea what to expect or need, maybe you will find something useful
Thanks for your help!!
A regulator after the SMPS seems a good idea as I regularly hear that SMPS have a lot of noise on the output rails, especially at high frequencies. Sure a regulator would get rid of at least a part of that.
What about pcb-layout?
In general pcb-layout seems critical; however here ICs do the PWM, so my impression is that in this special case the layout is not more critical than for other circuits- true?
Have fun, Hannes
A regulator after the SMPS seems a good idea as I regularly hear that SMPS have a lot of noise on the output rails, especially at high frequencies. Sure a regulator would get rid of at least a part of that.
What about pcb-layout?
In general pcb-layout seems critical; however here ICs do the PWM, so my impression is that in this special case the layout is not more critical than for other circuits- true?
Have fun, Hannes
Hi
Regulators won't regulate noise away, only good output filter of smps will minimize it as much as possible. I had no noise problems...
As for layout goes, apart from all the safetys you should take, it is pretty straightforward, you place element as you want them then start connecting, put them in groups or something, like primary side (caps and fets are near each other, so is trafo and so on), then secondary,.. Or copy someoes design and change something if you wouldn't like
Regulators won't regulate noise away, only good output filter of smps will minimize it as much as possible. I had no noise problems...
As for layout goes, apart from all the safetys you should take, it is pretty straightforward, you place element as you want them then start connecting, put them in groups or something, like primary side (caps and fets are near each other, so is trafo and so on), then secondary,.. Or copy someoes design and change something if you wouldn't like
So far I have found layout to be critical only in swithching amps, because of sensitive input circuit and high freq./high current output...if not done right you can have problems...but I didn't have this with any smps
Re: PCB for SMPS +/-50V
Hi Alex mm
Another nice board layout...
Do you mind sharing the PCB files? I am thinking about prototyping your board in the near future. The plan is to use this SMPS to power the DX HR Turbo.
Thanks!
alex mm said:Hi folks.
Another PCB variant
Hi Alex mm
Another nice board layout...
Do you mind sharing the PCB files? I am thinking about prototyping your board in the near future. The plan is to use this SMPS to power the DX HR Turbo.
Thanks!
Hi Eva,
that's exactly the problem. Finding a schematic, ideally with board layout (in my needed size
) of a proven, quiet SMPS. So one of yours would be nice.I've been looking for quite some time for such a thing, but usually it's not fully tested or it has tons of features I don't need (that I would need to strip from the board-layout) or is overkill power wise. Or uses a non-standard core so that one cannot clone it.
Or do you guys know a proven, quiet 300-400W SMPS for symmetric rails?
I would be interested to drop the usual transformer-psu and use such a thing for my power amp
Just for sake of doing something more interesting.Any links appreciated!
Have fun, Hannes
By the way, why's that SMPS-board that large? It's larger than a 300W transformer?
Why does it use 2x 470uF/400V caps? These don't exist on the schematic?
I suppose they replace the 4x 600uF/200V caps? I can't see the need for 400V parts here.
Guys, be aware that the layout is not 1:1 identical to the schematic.
Have fun, Hannes
Why does it use 2x 470uF/400V caps? These don't exist on the schematic?
I suppose they replace the 4x 600uF/200V caps? I can't see the need for 400V parts here.
Guys, be aware that the layout is not 1:1 identical to the schematic.
Have fun, Hannes
Hi Mahmood
Can you send to my email the file for the pcb layout as I cannot email you since I'm still on supervised by the moderator. and also can I use toroid transformer in the output and lastly if I want to convert to 13.6vdc as output what would be the winding in the transformer?
my email: stcboy2002@yahoo.com
thanks
Can you send to my email the file for the pcb layout as I cannot email you since I'm still on supervised by the moderator. and also can I use toroid transformer in the output and lastly if I want to convert to 13.6vdc as output what would be the winding in the transformer?
my email: stcboy2002@yahoo.com
thanks
request
hello
dear stcboy
please check your mailbox . in the zip file u can find
1: my spms main file that open with pad2pad software
2: an108 that is a smps calculations based on toroidal core
and this is good . from chas1:
calculating the volume for the transformer plus number of turns Post #5
To answer your question, you will find many methods for calculating turns and core size. I will try to explain a easy one for me. You must remeber all methods are based on Faraday's law and just rearranged so you can find the unknowns.
Faraday's law:
E= N*AE *(dt/dt) * E-8
E is the voltage across the transformer winding, N is the number of turns on the winding, Ae is area of core in cm^2, DB is flux change (gauss) and dt time for flux to change (seconds)
Now we rearrange the terms and plug in some definitions and we can get the following for finding number of primary turns.This is for halfbridge. For Forward or Fullbridge you double this number because they have to support the rectified mains not just half.
V(in) * E8 / (4 * Fs * Bmax *Ae) = NT(pri)
Now for the core volume to support the power we need:
Lets set up a design for 500watts:
The primary current will be equal to :
Ip= 3 *P(out) /V(in)
V(in) will be calculated based on 110VAC line at it highest value:
130 VAC therefore with a voltage doubler we can expect about:
2(130 * 1.4) = 370 VDC after rectifiers
therefore Ip = 1500 /370 = about 5 Amps from this we calculate the input power which is 1500/ .85 for 85% eff which is about 1750 watts.
core size = .68 * P(out) * current density / Fs * Bmax
Choose a industry standard of 500 c.m. /A for current density and we get:
AcAe = .68 * 1500 * 500E3 / 100E3(Fs) * 1200 (bmax) =4.25 cm^4
If we check the ETD49 specs we find that its AcAe is about 5.7 cm^4 which is a good choice for this design
Look what happens when we raise the Fs to 200KHz:
AcAe = .68 * 1500 *500e3 / 200e3(Fs) *1200(bmax) =2.125 cm^4
so you can see the higher the frequency the smaller the core within reason (copper loss, core temp and other things come into play)
In this case we used a Bmax of 1200 and could have used up to 1600, recalucate using 1600 and then we get 3. 18 cm^4 which means we might be able to use an ETD44 coreset now for the turns calculation:
If we use the highest voltage we expect on our transformer windings when the supply turnon:
N(pri) = 370(V(inmax)E8 / (4 * 100E3 * 2400(B(max) *2.11(Ae) =
18Turns for ETD49 and for ETD44 = 23 Turns
Now a good guess for the secondary is Ns = VS/VP I want an output of 35 volts , so that means after the rectifiers I need twice that and to help with transits and load changes I will increase that by 5% or so make it 80 volts , I expect at low line to have about 110 volts after the main rectifiers using a 110VAC input so now my secondary turns will be :
18*(80/110) = 13 turns make it 14, After you wind and test your transformer you might find you need to add or take off a winding or two. And at high line you wil need 11 turns make that 12.
So there is your transformer calculations regardless of how you do it the frequency along with the Amount of flux will determine the output power and the core size along with the size of the winding area and wire size.
All this is more or less what I have found in appnotes,books and other articles plus a little experience mixed in. It is up to the designer or DIY to verify this thru research and reading as this forum is full of material covering this subject and I will not get in a contest with which is right or wrong, however if you find an error or have a question I will try to help if I can and I will correct the errors you find ... just remeber a transformer is just that and the law and priciples for their design is basic and well documented its just when you lump them into a design at high frequency that a lot of care must be taken for them to provide proper results.
thank u chas1
chek this page for toroid core data table :
http://coremaster.com/2000_core.htm
hello
dear stcboy
please check your mailbox . in the zip file u can find
1: my spms main file that open with pad2pad software
2: an108 that is a smps calculations based on toroidal core
and this is good . from chas1:
calculating the volume for the transformer plus number of turns Post #5
To answer your question, you will find many methods for calculating turns and core size. I will try to explain a easy one for me. You must remeber all methods are based on Faraday's law and just rearranged so you can find the unknowns.
Faraday's law:
E= N*AE *(dt/dt) * E-8
E is the voltage across the transformer winding, N is the number of turns on the winding, Ae is area of core in cm^2, DB is flux change (gauss) and dt time for flux to change (seconds)
Now we rearrange the terms and plug in some definitions and we can get the following for finding number of primary turns.This is for halfbridge. For Forward or Fullbridge you double this number because they have to support the rectified mains not just half.
V(in) * E8 / (4 * Fs * Bmax *Ae) = NT(pri)
Now for the core volume to support the power we need:
Lets set up a design for 500watts:
The primary current will be equal to :
Ip= 3 *P(out) /V(in)
V(in) will be calculated based on 110VAC line at it highest value:
130 VAC therefore with a voltage doubler we can expect about:
2(130 * 1.4) = 370 VDC after rectifiers
therefore Ip = 1500 /370 = about 5 Amps from this we calculate the input power which is 1500/ .85 for 85% eff which is about 1750 watts.
core size = .68 * P(out) * current density / Fs * Bmax
Choose a industry standard of 500 c.m. /A for current density and we get:
AcAe = .68 * 1500 * 500E3 / 100E3(Fs) * 1200 (bmax) =4.25 cm^4
If we check the ETD49 specs we find that its AcAe is about 5.7 cm^4 which is a good choice for this design
Look what happens when we raise the Fs to 200KHz:
AcAe = .68 * 1500 *500e3 / 200e3(Fs) *1200(bmax) =2.125 cm^4
so you can see the higher the frequency the smaller the core within reason (copper loss, core temp and other things come into play)
In this case we used a Bmax of 1200 and could have used up to 1600, recalucate using 1600 and then we get 3. 18 cm^4 which means we might be able to use an ETD44 coreset now for the turns calculation:
If we use the highest voltage we expect on our transformer windings when the supply turnon:
N(pri) = 370(V(inmax)E8 / (4 * 100E3 * 2400(B(max) *2.11(Ae) =
18Turns for ETD49 and for ETD44 = 23 Turns
Now a good guess for the secondary is Ns = VS/VP I want an output of 35 volts , so that means after the rectifiers I need twice that and to help with transits and load changes I will increase that by 5% or so make it 80 volts , I expect at low line to have about 110 volts after the main rectifiers using a 110VAC input so now my secondary turns will be :
18*(80/110) = 13 turns make it 14, After you wind and test your transformer you might find you need to add or take off a winding or two. And at high line you wil need 11 turns make that 12.
So there is your transformer calculations regardless of how you do it the frequency along with the Amount of flux will determine the output power and the core size along with the size of the winding area and wire size.
All this is more or less what I have found in appnotes,books and other articles plus a little experience mixed in. It is up to the designer or DIY to verify this thru research and reading as this forum is full of material covering this subject and I will not get in a contest with which is right or wrong, however if you find an error or have a question I will try to help if I can and I will correct the errors you find ... just remeber a transformer is just that and the law and priciples for their design is basic and well documented its just when you lump them into a design at high frequency that a lot of care must be taken for them to provide proper results.
thank u chas1
chek this page for toroid core data table :
http://coremaster.com/2000_core.htm
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