But when I want to open this PNG file it opens HEX editor not circ cad?🙄
THIS is not SCH file just PNG file ? in post 95?!!
THIS is not SCH file just PNG file ? in post 95?!!
luka said:
ok but THIS is PNG file and I can not open it
I go open , I secelct PNG file and it opens HEX editor
Maxbe you uploaded wrong file
The file is a Zip.Inside of this Zip file is one file named Amp SMPS.sch.After you download circad98 demo and install it, you run circad98 and open with it file Amp SMPS.sch.
There is no PNG file, because this would be a picture.
There is no PNG file, because this would be a picture.
luka said:
ok I managed to open this file: this PNG i renamed to zip and extract
Now some questions about schematics:
Why are you usin T2?
Why are you using 3T WINDNIG on the main ferit:
are not this 100V zenners enough to make 7812Working?
You are using 1uF in serises with the primary winding: If I want more than 250W : insted 1000W (using) BIGGER ferit transforamtor do I have to change this 1uF ?
And can this schematics be used for higher powers?
Thanks
Update on HalfBridge VMC
Luka
How are you? , I haven't been monitoring the forum lately.
I have tested my proto-type and I will include a snap shot of my proto PCB. I have tested this supply under most conditions that would be encountered thru use and the performance is good for a DIY I think. I used the SG3525 in voltage mode control.
I have listened to a lot ot 60's rock and roll which are noted for the the bass for the sound test. The output regulation from light loads to full load is about 500mv. The efficiency is about 78%. It is very cool with one smalll PC fan. The final PCB will be ready
next week.
I am powering my 400 watt amp with this supply and they are very happy together.
Chas1
Luka
How are you? , I haven't been monitoring the forum lately.
I have tested my proto-type and I will include a snap shot of my proto PCB. I have tested this supply under most conditions that would be encountered thru use and the performance is good for a DIY I think. I used the SG3525 in voltage mode control.
I have listened to a lot ot 60's rock and roll which are noted for the the bass for the sound test. The output regulation from light loads to full load is about 500mv. The efficiency is about 78%. It is very cool with one smalll PC fan. The final PCB will be ready
next week.
I am powering my 400 watt amp with this supply and they are very happy together.
Chas1
Attachments
medogrizli
What are your questions? do they refer to a particular schematic
or they general in nature? Are you trying to construct a supply from someone else's schematic's?do you have publications that you can refer to that can aid in construction or design.
Note: An offline supply while simple looking is very dangerous
and can injure you from high voltages, exploding parts during
test and construction so be careful. That said you can find a very good constuction article and a parts kit to build one at a-and-t labs.com. This is a fullBridge, but if you half the winding's and remove two mosfets and make some other minor changes it is a
Halfbridge.
chas1
http://www.a-and-t-labs.com
What are your questions? do they refer to a particular schematic
or they general in nature? Are you trying to construct a supply from someone else's schematic's?do you have publications that you can refer to that can aid in construction or design.
Note: An offline supply while simple looking is very dangerous
and can injure you from high voltages, exploding parts during
test and construction so be careful. That said you can find a very good constuction article and a parts kit to build one at a-and-t labs.com. This is a fullBridge, but if you half the winding's and remove two mosfets and make some other minor changes it is a
Halfbridge.
chas1
http://www.a-and-t-labs.com
chas1
Yea I haven't been here for a long time to.
That's great!!😀 You say that is your prototype, but pcb looks like from a pro.Didn't you use mc34025 in current mode?I gues that is not the full bridge.But hey it looks great, and probably performance is to.Just the thing I would need.Why is efficiency so low? Too small consumption for it to work at higher efficiency.How much power do you think it would produce if necessary?Since this is not full bridge can you post shema?
oo and Nice looking board, again!!
Yea I haven't been here for a long time to.
That's great!!😀 You say that is your prototype, but pcb looks like from a pro.Didn't you use mc34025 in current mode?I gues that is not the full bridge.But hey it looks great, and probably performance is to.Just the thing I would need.Why is efficiency so low? Too small consumption for it to work at higher efficiency.How much power do you think it would produce if necessary?Since this is not full bridge can you post shema?
oo and Nice looking board, again!!
chas1 said:
Questions about LUKAs schematics
ok I managed to open this file: this PNG i renamed to zip and extract
Now some questions about schematics:
Why are you usin T2?
Why are you using 3T WINDNIG on the main ferit:
are not this 100V zenners enough to make 7812Working?
You are using 1uF in serises with the primary winding: If I want more than 250W : insted 1000W (using) BIGGER ferit transforamtor do I have to change this 1uF ?
And can this schematics be used for higher powers?
Thanks
Full Bridge
Luka
This is halfbridge and can be used over 600watts, I have not tested beyond that but with the parts I used should go to over 1kW.
I have the current mode supply almost finished but I have second thoughts about using current mode and will change it to voltage mode which I think is best suited for audio amp power supply because of the complex load requirements, I will use the MC33025P.
Thanks for the comments on the PCB but it is a board I designed to test fullbridge, halfbridge, pushpull and forward converter topologies that is why you don't see the input power nor the low voltage for the PWM and the PWM module is a plugin for different types of control also on the pcb I have circuits for different type compensation of feedback loops and the pcb is big enough to allow for easy testing of all circuits.
After I assemble the final pcb and all is well , I will supply all schematics and doc's so anyone who likes can construct this supply.
chas1
Luka
This is halfbridge and can be used over 600watts, I have not tested beyond that but with the parts I used should go to over 1kW.
I have the current mode supply almost finished but I have second thoughts about using current mode and will change it to voltage mode which I think is best suited for audio amp power supply because of the complex load requirements, I will use the MC33025P.
Thanks for the comments on the PCB but it is a board I designed to test fullbridge, halfbridge, pushpull and forward converter topologies that is why you don't see the input power nor the low voltage for the PWM and the PWM module is a plugin for different types of control also on the pcb I have circuits for different type compensation of feedback loops and the pcb is big enough to allow for easy testing of all circuits.
After I assemble the final pcb and all is well , I will supply all schematics and doc's so anyone who likes can construct this supply.
chas1
T2 is input filter
3 turns on main ferrite are for working supply for controler
They are not because, controler + IR must have larger amount of current,which zeners can't provide.
Yes I am using 1uF in series with primary, but I would have to use biger one.For this smps my aim is about 500w.So if you want 1kw you need bigger input caps like 2000uF+,ferrite doesn't have to bi bigger,that depends on freq.Series cap must be bigger,...
But I suggest that you go for smaller power for the first time and
1kw would be better to use full bridge
3 turns on main ferrite are for working supply for controler
They are not because, controler + IR must have larger amount of current,which zeners can't provide.
Yes I am using 1uF in series with primary, but I would have to use biger one.For this smps my aim is about 500w.So if you want 1kw you need bigger input caps like 2000uF+,ferrite doesn't have to bi bigger,that depends on freq.Series cap must be bigger,...
But I suggest that you go for smaller power for the first time and
1kw would be better to use full bridge
luka said:
irfp460 is MORE than enough for more than 2 kW HALF bridge...
Why do you suggest full bridge?
So : T2 : input filter is this necessary? What are characteristics of this input filter
they why are you using zenners: How can controller start without enough current form zenners and on the T3 are NO current because controller is not working yet : you mean zenners are enough for first cycle? and than T3 powers controller after that...
What is the raletion od capacitor in series and POWER of main ferrit?
I would agree. But I would use current mode only for current limiting if short circuit would occure.
Can't wait for your final product.
Maybe you will share pcb with me.Have so much amps,that I can't use because they are not in some sort of case.I have to sell it, don't have any use of them.
Maybe you will share pcb with me.Have so much amps,that I can't use because they are not in some sort of case.I have to sell it, don't have any use of them.
overcurrent protection
Luka
The supply does not have to be a current mode for over current protection, the supply that I posted a pix of has this feature and it works when activated.
This is the basic's , the current thru the primary is monitored with a current transformer, which feeds a bridge that outputs a voltage based on the current in the primary of the main xfmr and when it exceeds a preset value the pwm chip is disabled until the problem is corrected.
As I said I will post pcb along with the schematics when finished, also the halfbridge can be designed for more than a kW, one of the limiting factors were low price mosfet's that could handle 12 amps before has been overcome by the new IGBT's.
I hate to say this but if you need more power you might want to consider a two switch forward converter for simplicity before a fullbridge.
chas1
Luka
The supply does not have to be a current mode for over current protection, the supply that I posted a pix of has this feature and it works when activated.
This is the basic's , the current thru the primary is monitored with a current transformer, which feeds a bridge that outputs a voltage based on the current in the primary of the main xfmr and when it exceeds a preset value the pwm chip is disabled until the problem is corrected.
As I said I will post pcb along with the schematics when finished, also the halfbridge can be designed for more than a kW, one of the limiting factors were low price mosfet's that could handle 12 amps before has been overcome by the new IGBT's.
I hate to say this but if you need more power you might want to consider a two switch forward converter for simplicity before a fullbridge.
chas1
Does not? Hmm that is great news to me.
If you don't mind telling me how did you winded your trafo?
Is it 24pri and 10sec, or do you have lower sec turns?
If you don't mind telling me how did you winded your trafo?
Is it 24pri and 10sec, or do you have lower sec turns?
Transformer design
Luka
To expand the answer about current limiting since you have Brown's book refer to page 184 , you will see a diode bridge consisting of 1n914's with a 62 ohm burden resistor across the secondary. The output of this bridge is connected thru a voltage divider to the fault pin of the MC34067(pin 10), if this pin exceeds the value of your current limit it will create a fault and shutdown the PWM chip. Take a look at page 185 for explaination of calculating the values. In the case of the SG3525 this would be the shutdown signal(also pin 10). these pins can be used to monitor all your faults (temp, over voltage, currrent and others)with the right support circuit. with some thought you can tie in a circuit to monitor dc in your speakers and shut down the supply until you fix the problem. You can or tie a lot of faults to these pins.Be careful you could pick up a lot of noise on this pin and it would cause all kinds of problems (SG3525!!!!)
I refer to this circuit because it is ZVS controller which is voltage mode control.
Using current mode is regulating the supply using load currrent and voltage mode is regulating the supply using load volatge, current mode requires two loops and voltage mode requires one loop to regulate the supply. Current mode is faster???
For my transfomer I have wound four, the one shown in photo has 22 turns in the primary and a center tap 14 turn secondary. 22 - 7 - 0 - 7. I used Brown's method to calculate turns. The transformer also has four faraday shields.
This was only to test my design since I only have a 400watt amp
the other transformers are wound for an +/- 70 volt rails.
chas1
Luka
To expand the answer about current limiting since you have Brown's book refer to page 184 , you will see a diode bridge consisting of 1n914's with a 62 ohm burden resistor across the secondary. The output of this bridge is connected thru a voltage divider to the fault pin of the MC34067(pin 10), if this pin exceeds the value of your current limit it will create a fault and shutdown the PWM chip. Take a look at page 185 for explaination of calculating the values. In the case of the SG3525 this would be the shutdown signal(also pin 10). these pins can be used to monitor all your faults (temp, over voltage, currrent and others)with the right support circuit. with some thought you can tie in a circuit to monitor dc in your speakers and shut down the supply until you fix the problem. You can or tie a lot of faults to these pins.Be careful you could pick up a lot of noise on this pin and it would cause all kinds of problems (SG3525!!!!)
I refer to this circuit because it is ZVS controller which is voltage mode control.
Using current mode is regulating the supply using load currrent and voltage mode is regulating the supply using load volatge, current mode requires two loops and voltage mode requires one loop to regulate the supply. Current mode is faster???
For my transfomer I have wound four, the one shown in photo has 22 turns in the primary and a center tap 14 turn secondary. 22 - 7 - 0 - 7. I used Brown's method to calculate turns. The transformer also has four faraday shields.
This was only to test my design since I only have a 400watt amp
the other transformers are wound for an +/- 70 volt rails.
chas1
Medogrizli,
Fullbridge has one cap for entire rectified main AC voltage.In fullbridge you drive entire voltage (300V+) in one direction on main trafo and then in opposite direction. In halfbridge main voltage is divided among two caps in series,voltage is half that big (150v+) as in fullbridge, with which you drive main trafo at any given time.Since power is equal to voltage times current,this means that you will need to supply main trafo with two time as big current as in fullbridge to get the same power.Any low freq.(100 or 120 Hz) voltage ripple on primary side will transfer to secondery if it is not small enought. To get rid of that you will need big cap bank (3000 or 4000uF for 150v+,that is 6000uF or 8000uF total for entire main voltage for let say 2kw halfbridge) on primary side.So there is some practical limit for where to use halfbridge.There is no point to build 2kw halfbridge since the cost of the elements would be many times bigger as in fullbridge.And there is also primary current that is reather big for that power. You would need big trafo only to put all of the cupper wire inside of it.
As for the zeners,I have change that part of the circuit.Why? Zeners in my opinion (and my test) don't supply enough current for controler to start.And even if they would the power dissipation for that time would be too much for zenners to handle.
What is the relation of capacitor in series with main trafo?
There is relation.You can find it in Abraham Pressman - Switching power supply design (2nd ed.).
Cb=Iprimary-peak x (Ton/2)/dV where dV is voltage on this cap.You chose it and chese it 16v max or less.
A tolerable droop in the primary voltage pulse is about
10 percent or about 14 V. For 150 W and Vdc of 272 V, Ipft is, from Eq.
3.1, Ipk = 3.13 x 150w/272v = 1.73 A. Then from Eq. 3.4, Cb = 1.73 x
0.8 x 5 x 10-6/14= 0.49uF. The capacitor must, of course, be a nonpolarized
type.
Fullbridge has one cap for entire rectified main AC voltage.In fullbridge you drive entire voltage (300V+) in one direction on main trafo and then in opposite direction. In halfbridge main voltage is divided among two caps in series,voltage is half that big (150v+) as in fullbridge, with which you drive main trafo at any given time.Since power is equal to voltage times current,this means that you will need to supply main trafo with two time as big current as in fullbridge to get the same power.Any low freq.(100 or 120 Hz) voltage ripple on primary side will transfer to secondery if it is not small enought. To get rid of that you will need big cap bank (3000 or 4000uF for 150v+,that is 6000uF or 8000uF total for entire main voltage for let say 2kw halfbridge) on primary side.So there is some practical limit for where to use halfbridge.There is no point to build 2kw halfbridge since the cost of the elements would be many times bigger as in fullbridge.And there is also primary current that is reather big for that power. You would need big trafo only to put all of the cupper wire inside of it.
As for the zeners,I have change that part of the circuit.Why? Zeners in my opinion (and my test) don't supply enough current for controler to start.And even if they would the power dissipation for that time would be too much for zenners to handle.
What is the relation of capacitor in series with main trafo?
There is relation.You can find it in Abraham Pressman - Switching power supply design (2nd ed.).
Cb=Iprimary-peak x (Ton/2)/dV where dV is voltage on this cap.You chose it and chese it 16v max or less.
A tolerable droop in the primary voltage pulse is about
10 percent or about 14 V. For 150 W and Vdc of 272 V, Ipft is, from Eq.
3.1, Ipk = 3.13 x 150w/272v = 1.73 A. Then from Eq. 3.4, Cb = 1.73 x
0.8 x 5 x 10-6/14= 0.49uF. The capacitor must, of course, be a nonpolarized
type.
What do you use instead of the zeners for start up?
A problem (which you may have already discovered) with the zeners is that if the mains voltage changes a little the current through them will change a lot. If the mains is low it won't start and if it's high they will fry... 10% change in mains voltage will change the voltage remaining after the zeners with 30V...
A problem (which you may have already discovered) with the zeners is that if the mains voltage changes a little the current through them will change a lot. If the mains is low it won't start and if it's high they will fry... 10% change in mains voltage will change the voltage remaining after the zeners with 30V...