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    Sticky: CF139 is a little bit better core material than...

    CF139 is a little bit better core material than N87 TDK.

    Your primary winding can be 28 turns instead of 30 turns. (input 230vac)
    Using this formula then 155v/ 28t = 5.53 volts per turn ...
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    Sticky: Primary winding 30 turns. (15T +15T) ECW 4...

    Primary winding 30 turns. (15T +15T) ECW 4 wires 0.5mm twisted together. Leave 4mm margin space at bobbin cheeks on each side.

    Secondary 10 turns. for single winding if you want double...
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    I will try to answer your questions to the best...

    I will try to answer your questions to the best of my knowledge. I am also a hobbyist just like you.

    1) As I can really see it may be controlling hysteresis in the opamp (The reaction time...
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    The topology used is Half bridge as this is a...

    The topology used is Half bridge as this is a modified ATX supply. You will find some schematics that I made during the build but I never came to make a proper one. They are all drawn in pencil. ...
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    I can give you an idea how to combine the LM317...

    I can give you an idea how to combine the LM317 to regulate the feedback for the TL494 . The switching regulator (tl494) will follow the input to the LM317 with a little more voltage (4V) This will...
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    Well getting to such small pulse width eventually...

    Well getting to such small pulse width eventually the system goes in discontinuous mode that means it start switching on and off with such a small current. It is not so easy to get to such low...
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    @FIFI-22 Have you tried to decouple the feedback...

    @FIFI-22 Have you tried to decouple the feedback rail going to pin 3? It might shunt down any oscillations. A series filter formed by a capacitor and resistor in series between the feedback line and...
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    Hi its good to know that you are progressing in...

    Hi its good to know that you are progressing in the converter. Regarding the different transformers it might be the case that some of them are designed for a different operating frequency.

    From...
  9. Hello Yokan, It does not work the way you are...

    Hello Yokan, It does not work the way you are expecting. The duty cycle of the pwm varies not only to maintain the voltage but also to maintain the current drawn at any point. If say you have 5v...
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    I just told you in the last post your minimum...

    I just told you in the last post your minimum will be 4000uF and your maximum will be around 12000uF
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    It depends on the power needed well for example...

    It depends on the power needed well for example 5v@40A = 200w 25v @ 40A = 1000w. It also depends on the ripple wanted at the output. As a rule of thumb the input capacitance will be 1uf to 3uF...
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    Sticky: Regarding the threshold voltage which the over...

    Regarding the threshold voltage which the over current protection triggers is around 2.5v. As you can see the rail voltage to the opamp is 5v, this is divided by 2 with R123 and R118. (22K) creating...
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    Sticky: Hi Ravs, I see no detail in schematic for the...

    Hi Ravs, I see no detail in schematic for the current transformer however in my version I used a ratio of 22:1. I suggest you select a green core instead and the diameter of this core may also be...
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    The compensation and feedback is all there in the...

    The compensation and feedback is all there in the schematic.

    Regards, Silvio
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    I just realized that our friend is using an...

    I just realized that our friend is using an IR2153 chip however the chip cannot be regulated. The output inductor is not really needed and maybe only a small one is necessary such as 6uH to block...
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    @ norazmi I think there is a little error...

    @ norazmi
    I think there is a little error regarding the transformer details. An ER35 has a center core diameter of 1.1cm^2 and not 1.3cm. Regarding the formula itself I guess the voltage at the...
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    As far as I can see the pulse is not right on all...

    As far as I can see the pulse is not right on all the scope shots. The pulse should show more like a square wave rather than a spike.
    The configuration of the TL494 is rather odd, to my believe...
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    Well this is up to you if you are to abandon the...

    Well this is up to you if you are to abandon the simple circuit. All i can tell you be aware of fake chips, my experiance with this is hell when i was building my first smps. If you like to know...
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    @FiFi 22 Hello fifi I had just seen your post...

    @FiFi 22

    Hello fifi I had just seen your post and I am going to try to help you solve your problem.
    A few things to consider.
    A transistor in an smps is usually switched hard in each duty cycle...
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    I read the same thing while reading Tahmid's blog...

    I read the same thing while reading Tahmid's blog way back a few years ago when I was learning about smps. This guy used 1K resistors, which I think now its a bit too much and will waste energy...
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    I guess you did not understand our friend Deltor,...

    I guess you did not understand our friend Deltor, If you intend to use a pull down resistor this is there so that any build up charge on the gates will be discharged. This will only help in the...
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    Sticky: Hello again, I made some calculations and found...

    Hello again, I made some calculations and found out that one core can give the power needed. I would rather go for full bridge at this power. I cannot read Russian and do not know exactly the...
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    Hello Steven, I was just looking at the...

    Hello Steven, I was just looking at the schematic and these are a few of my taughts.

    1) Why is the PFC voltage set so low? Usually we start at around 360 to 380vdc. Do not forget that the mains...
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    I sent you email with spreadsheet of NCP1653 pfc...

    I sent you email with spreadsheet of NCP1653 pfc chip
  25. My setup powering an 8w lamp 12v. The supply...

    My setup powering an 8w lamp 12v. The supply input was 16v
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