Audio smps 700w (IR2153)

For the protection to reset you need to disconnect from mains and wait for the bulk capacitor to discharge.
I have waited a long time after disconnecting it, I also discharged the main cap (electrolytic) C5, C6, C7 with a lamp, the same I did with the C8 cap. But when you turn on the source it starts protected, the only thing that restores it is to move the trimmpot.
 
For the protection to reset you need to disconnect from mains and wait for the bulk capacitor to discharge.
I have downloaded C5, C6, C7, etc, etc and when I turn on the source it starts protected. The only way it is unprotected is by moving the adjustment preset or by bridging the base and emitter of the 5551.
 

Silvio

Active member
I have downloaded C5, C6, C7, etc, etc and when I turn on the source it starts protected. The only way it is unprotected is by moving the adjustment preset or by bridging the base and emitter of the 5551.
I don't know if you have included the high frequency soft start. I don't know if you have included the secondary output inductors either.
What is the output capacitance that you are using on each rail? which pin header did you build? I had 3 options
1) With current limiter, 2) Protection with schmitt trigger, and 3) Protection with high frequency soft start and scr protection
I would like to see a picture of your pcb.
What is happening is that on startup the secondary capacitors are presenting a very low impedance and triggering your overload protection.
The IR2153 does not have a soft start and has to be provided externally, especially if there is more than 2000uF on each rail on the secondary.
 
I don't know if you have included the high frequency soft start. I don't know if you have included the secondary output inductors either.
What is the output capacitance that you are using on each rail? which pin header did you build? I had 3 options
1) With current limiter, 2) Protection with schmitt trigger, and 3) Protection with high frequency soft start and scr protection
I would like to see a picture of your pcb.
What is happening is that on startup the secondary capacitors are presenting a very low impedance and triggering your overload protection.
The IR2153 does not have a soft start and has to be provided externally, especially if there is more than 2000uF on each rail on the secondary.
The PCB that I show below is based on your schematic (I saw it on PCBshare) but looking deeper is that I came to this forum and found that it was originally from you.
My smps has 940uF / 100V per rail (2 * 470uF in parallel).
Protection is SCHMITT TRIGGER.
Momentarily I removed the coil that filters the AC input and also the DC output.
sssssss.jpeg
 

Silvio

Active member
To tell you the truth although I designed the schmitt trigger version I never tried it for real on the smps.
Things you can try
1) You can remove the input thermister and put a 5watt 47R resistor instead. To help a slower start up
2) Following my schematic for schmitt trigger there is a decoupling capacitor which is coming from the sample diodes (1N4148) and has a value of 220nF, You can rise the value slowly 1uF- 4.7uF until you get a start up without tripping on the surge current, Keep to the minimum possible otherwise during a short circuit your fets will not be saved.
 
To tell you the truth although I designed the schmitt trigger version I never tried it for real on the smps.
Things you can try
1) You can remove the input thermister and put a 5watt 47R resistor instead. To help a slower start up
2) Following my schematic for schmitt trigger there is a decoupling capacitor which is coming from the sample diodes (1N4148) and has a value of 220nF, You can rise the value slowly 1uF- 4.7uF until you get a start up without tripping on the surge current, Keep to the minimum possible otherwise during a short circuit your fets will not be saved.
I have put the setting to the minimum, I do not think that the soft start will solve it since when the source is protected by protection, for some reason and no matter how much capacitors are discharged, it starts again protected.
However, if I make a bridge between the base and emitter of the 5551, the protection is removed, leaving me to have output voltage. I proceed to disconnect the source, turn it back on and it turns on without any problem.
A colleague told me to implement the following:
WhatsApp Image 2021-05-27 at 19.17.01.jpeg
Although I would not know well what values to place.
R, C y Tr

Greetings!
 

Silvio

Active member
From what you are telling me
Do you have discharge resistors on the high voltage DC line?
You can also try reducing the value of the 4.7K resistor (2.2K) at the base of 2n5401.
Try also enlarge the 100nF capacitor at the base of 2n5551 (1uF)
 
From what you are telling me
Do you have discharge resistors on the high voltage DC line?
You can also try reducing the value of the 4.7K resistor (2.2K) at the base of 2n5401.
Try also enlarge the 100nF capacitor at the base of 2n5551 (1uF)
I have 150K resistors to discharge C6 and C7.
I have lowered the value of the R of 4K7 associated to the Vr1 (for one of 3K) without obtaining different results, I replaced 4K7.
I will change those two values that you just indicated and notice that it happens.

PS: my Vr1 is 5K (is there a problem with that?)
 

Silvio

Active member
PS: my Vr1 is 5K (is there a problem with that?)

No there should not be a problem with that
Try to use a lower value like I said 2k2 resistor
 
PS: my Vr1 is 5K (is there a problem with that?)

No there should not be a problem with that
Try to use a lower value like I said 2k2 resistor
I changed the R from 4k7 to one of 2k2 (C is still 100nF) the protection once activated does not not even if you turn off the power supply and reconnect it
 
Change also the capacitor it is important to minimize the sensitivity
I have also changed the value of C from 100nF to 1uF, in addition to the R that he had told me of 2K2.
Unfortunately, the source still does not reset by itself, nor by disconnecting from the electrical network.
 

Silvio

Active member
The V2 file with high frequency soft start and SCP with scr and current transformer works 100% This is the version I have now. You can see it on youtube.
About the current transformer it is 80-0-80 turns with 0.16mm wire. About the 1.5 turn coupling loop it is simply passed in the middle of the core and crossed on the bottom. I will show you a picture later how to do it.

You can also make a push button switch on your current pin header and solder two wires across the base emitter of the 2n5401 to reset it. If you this modification you can put the original value of the capacitors and resistors.
 
Last edited:
The V2 file with high frequency soft start and SCP with scr and current transformer works 100% This is the version I have now. You can see it on youtube.
About the current transformer it is 80-0-80 turns with 0.16mm wire. About the 1.5 turn coupling loop it is simply passed in the middle of the core and crossed on the bottom. I will show you a picture later how to do it.

You can also make a push button switch on your current pin header and solder two wires across the base emitter of the 2n5401 to reset it. If you this modification you can put the original value of the capacitors and resistors.
I will be trying different things for the protection that I have at the moment. But I'll be waiting for the CT80 to be published sometime, at the moment I only have 0.45mm / 0.7mm / 1mm wires.
I really liked this compact source with EE42 I got 800W continuous and it has 12V outputs for coolers, mp3 / bluetooth module and + -12V for some preamp. It only remains that the protection stage looks good (for me).
Greetings!
 

Silvio

Active member
A picture of a center tapped current transformer. Note the 1.5 turn coupling loop in the bottom.

Current trafo.JPG
 
A picture of a center tapped current transformer. Note the 1.5 turn coupling loop in the bottom.

View attachment 7395
Silvio, good afternoon.
I was thinking of redesigning the mini IC PCB so I can keep my power PCB. So I have the following question:
The RC-CC set on the V2 smps takes from the center of C6-C7, but your mini oscillator PCB has that RC-CC set connected to pin # 6 of the IC.
Is the same???
Is it okay to take from one end or the other of the primary winding?
Greetings!
IvanElectric
 

Silvio

Active member
Just to let you understand more the schematic. Pin 6 is VS, that is the centre between the 2 mosfets. Here the direction of current flow changes polarity every half cycle.
As more current is drawn by the mosfets a ripple is generated the more current the larger the amplitude of the ripple. We are now sensing this AC ripple but blocking any DC path with the small capacitor.
Now this ripple is rectified and sampled so that when a certain voltage is reached it will trigger the protection. In the V2 an SCR. this scr will pull the supply pin to ground hence switching off the smps.

It is now important to add again the 200R resistor and remove the diode at the start up section. The scr when trggers stays on until the smps is disconnected. If left on without this resistor it will eventually burn the transistors in the startup circuit due to excessive curent.
 
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