Audio smps 700w (IR2153)

Silvio

Active member
hi sir i have made this from your design there might be small changes based on my parts available, i had it with 50vdc rails using most parts from ATX psu. i do not expect high efficiency due to the parts i made and this is just for fun. i am powering my 2x100W amplifier. but i have some situation every time i shut it down/turn off the SMPS cannot be turned on again immediately and the protect led will turn on. the result was i cannot use it back again for several minutes (10-20minutes) just to discharge the caps before it will turn on again. by the way it was 2x680uf in main and 2x100k1w resistors,

thank you
sam View attachment 7017

Show me the schematics of your new setup and I can see what you have changed maybe I can help you solve the problem.
 

MicrosiM

Administrator
Staff member
@ xuantunt

Turning a DIY product into a commercial product without permission?

Your account is disabled now, you wont be able to join again.

Thanks Silvio
 

rinchz

New member

Silvio

Active member
hi sir i am sorry for taking so long for replying you. i have found the schema it was from maxente but i know you can give me some advice View attachment 7023
i have a problem on posting multiple files for now, i do not know maybe my membership category... View attachment 7024
i was trying to learn upload multiple files,
View attachment 7025
here was the board i made for the mentioned SMPS earlier that has a problem.
thank you

Please post schematic so that I can follow what is there on the pcb.
 

Silvio

Active member
Hello rinchz, From what I see from your schematic it seems that you have a totally different setup from mine. The soft start is kind of different having a resistor in the middle of the half bridge and then shunted by a relay after a few seconds. This also works good.

Secondly I see that the gate resistors seem a bit too small for the IRF840 these should be 22 ohms otherwise you will load the IR2153. If you change the gate resistors to 22 ohms then put a small diode such as 1n4148 across the resistor with the anode pointing at the gate. (See my schematic)

The bootstrap capacitor should be between 0.5uF- 1uf. (yours is 10uf) Use a good quality one. A film capacitor is better

Put a 47K resistor across each bulk capacitor(680uf) so that it helps divide the voltage properly and also discharge the capacitors when the smps is turned off. With this value it should take no more than 0.5 to 1 min to discharge the capacitors.

Your overload protection is built up with a current transformer and a shmitt trigger. It seems to me that the shmitt trigger is working prematurely. This could be for two reasons. 1) the soft start resistor is not large enough (try a larger value like 47 ohms) 2) it could be you need more decoupling along the lines feeding the shmidtt trigger. Try a 470nf (0.5uf) across the 22 ohm resistor to help smooth out the spikes generated from the current trafo.

Some questions for you.

1) Did you try to load the smps while it is working?
2) How much did you load it?
3) Did you check the voltage arriving at pin 1 of the IR2153 while the smps is working? Is it 15v?
4) 33Khz seems a good frequency but keep in mind that usually ATX smps works at around 20Khz. Due to this the transformer may not give you enough power. The copper wire used in them usually 0.8mm and this is not suitable for a higher frequency than 25Khz
5) Are your 2 transformers alike? Are they taken out from the same type of atx power supply? It could be that they may be using different frequencies and the windings tend to be different from one another. IF not you may experience different voltage drop on load between the two rails.

Lastly be aware of your probes sliding and touching something else while testing. Solder up some loops on the copper side so that you can hook your probes to them. Take some time and be careful its better safe than sorry.

Good luck
 

rinchz

New member
Hello rinchz, From what I see from your schematic it seems that you have a totally different setup from mine. The soft start is kind of different having a resistor in the middle of the half bridge and then shunted by a relay after a few seconds. This also works good.

Secondly I see that the gate resistors seem a bit too small for the IRF840 these should be 22 ohms otherwise you will load the IR2153. If you change the gate resistors to 22 ohms then put a small diode such as 1n4148 across the resistor with the anode pointing at the gate. (See my schematic)

The bootstrap capacitor should be between 0.5uF- 1uf. (yours is 10uf) Use a good quality one. A film capacitor is better

Put a 47K resistor across each bulk capacitor(680uf) so that it helps divide the voltage properly and also discharge the capacitors when the smps is turned off. With this value it should take no more than 0.5 to 1 min to discharge the capacitors.

Your overload protection is built up with a current transformer and a shmitt trigger. It seems to me that the shmitt trigger is working prematurely. This could be for two reasons. 1) the soft start resistor is not large enough (try a larger value like 47 ohms) 2) it could be you need more decoupling along the lines feeding the shmidtt trigger. Try a 470nf (0.5uf) across the 22 ohm resistor to help smooth out the spikes generated from the current trafo.

Some questions for you.

1) Did you try to load the smps while it is working?
2) How much did you load it?
3) Did you check the voltage arriving at pin 1 of the IR2153 while the smps is working? Is it 15v?
4) 33Khz seems a good frequency but keep in mind that usually ATX smps works at around 20Khz. Due to this the transformer may not give you enough power. The copper wire used in them usually 0.8mm and this is not suitable for a higher frequency than 25Khz
5) Are your 2 transformers alike? Are they taken out from the same type of atx power supply? It could be that they may be using different frequencies and the windings tend to be different from one another. IF not you may experience different voltage drop on load between the two rails.

Lastly be aware of your probes sliding and touching something else while testing. Solder up some loops on the copper side so that you can hook your probes to them. Take some time and be careful its better safe than sorry.

Good luck

thank you for the reply sir and for reminding me for safety that is my foremost concern also. i've been doing electronic hobby for more than 10years and i am working relative to electrical. i will do it as soon as i can get home...

i will do it as soon as i can get home...
 

rinchz

New member
hello sir silvio,
i had a little time though, heres what i did

the gate resistors changed to 22R with 4148 in parallel
bootstrap was changed to 470nF Mylar
100K on 680uF was not changed to 47K
softstart resistor was not changed but 470nF was added across 22R
Q...
1. yes +/- 50VDC
2. 2x100watt amp
3. 14.9V
4,5. ATX Cores are identical both were rewound using 0.5mm wires 20 turns half primary +same as the other half at the end

the main problem of premature triggering of pro was now solved. i can turn On and Off the SMPS even the music was playing.
i didn't have the time to test the max current/power from the SMPS. i'll give update next time.
by the way thanks for the safety reminders i used 30A 6mA GFCI as mains and 1k5AVR in testing SMPS while i do not have time to wind a 1:1 trafo

thank you sir...
rinchz,
 

quadtech

New member
Hi Rinchz, very interesting. Maybe you can create a new thread.
This looks low cost audio SMPS with easily available parts.

Pl post all the details with pictures and the detail of ATX secondary windings also.
 

rinchz

New member
Hi Rinchz, very interesting. Maybe you can create a new thread.
This looks low cost audio SMPS with easily available parts.

Pl post all the details with pictures and the detail of ATX secondary windings also.

that was already there in the other thread uploaded by maxente i just cant find it right now, i have a little time, were about to leave for work i will post that link soon...
 

Davidson

New member
Good day sir
Thanks for your good works..Please am new here. My question is this
I saw your input large bulk capacitor is just one instead of two.Rather you replaced the two bulk input divider capacitor with snall CBB polypropylene capacitors. Yes I know that that voltage will be halfed but will the little caps stand a full power load of 700w?
I will be glad if you can post your answer for me in my email davidokem08@gmail.com. Am still studying the use of this diysmps interface
Thanks
 

Silvio

Active member
@Davidson

Regarding the CBB caps yes they are enough and can pass all the current needed. I could also have use 0.47uF if I wanted. You will find out while you read on.

What would you say if you saw 2.5Kw smps for a pro amp and this capacitor value is 0.47uF.
Just to let you know in my setup of the 700w smps these are doing two purposes. 1) they divide the voltage of the bus and 2) they serve also as a DC blocking capacitor.

In this configuration the reflected value of these two capacitors will be doubled. To make it more clear for you the value of these capacitors is 1uF each but the reflected value is 2uF as seen by the half bridge. This way each capacitor works at 50% duty cycle and will surely last more. Here these capacitors take a lot of beating and it is important that they will be of good quality and low ESR, also the voltage rating will be double of what passes in them. In this case I used 400v rating cbb caps.

If it had to be with two electrolytic capacitors to make the half bridge and only one blocking capacitor especially in high power smps I often see these being 600v rated, however in small and medium rated smps 400v will be adequate.

Regards Silvio
 

Silvio

Active member
Hi steven
I am not sure what he used exactly but make sure that the voltage rating of these mosfets be 600v or more. There are a lot of high voltage spikes in this area of the smps. The fact that he used two in parallel is due to the mosfets be of adequate current handling. 4kw at 400v is 10A and at lower voltage this will be higher. Mosfets cannot work at there peak current and here I guess working at 25% current rating will make a good choice. My guess he used 2 mosfets of 20A rating.

I hope this helps Regards Silvio
 

stewin

Member
Hi steven
I am not sure what he used exactly but make sure that the voltage rating of these mosfets be 600v or more. There are a lot of high voltage spikes in this area of the smps. The fact that he used two in parallel is due to the mosfets be of adequate current handling. 4kw at 400v is 10A and at lower voltage this will be higher. Mosfets cannot work at there peak current and here I guess working at 25% current rating will make a good choice. My guess he used 2 mosfets of 20A rating.

I hope this helps Regards Silvio

hi Silvio thanks for the reply .

Will a irfp 460 lc work it has 20amps ?
 

Silvio

Active member
@ Stewin,

IRFP460 may work here as the voltage rating (500v) though is rather close to the peak operating voltage. A mosfet rated at 600v will be a better choice. Do not forget that here spikes are generated and 500v may be easily exceeded. It is worth a try but see that you fit an adequate snubber to suppress as much as possible. The type of core is also important here as some cores may generate spikes more than others. (my experience). Make a coupling loop on the PFC inductor and check with the oscilloscope. You can easily make out the voltage according to the turns ratio between the PFC inductor and the coupling loop.

Good luck and God bless you.
 
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