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Thread: sg3525/ir2110 half bridge

  1. #11
    @ Yoosef

    10 Years ago with my first attempt to build a SMPS, I built that circuit, and it worked fine, it was my first regulated SMPS.

    But I never completed a regulated SMPS, at least in the last year.

    But now I am moving to the new LLC SMPS topology.

    ======

    @ Silvio

    I had my ETD39 working fine with 20 Turns at primary. what core temperature you have in idle with your ETD39? at 28 Turns in primary?

    Maybe there is a reason?
    www.diysmps.com & www.Micro-Audio.com

  2. #12
    Quote Originally Posted by MicrosiM View Post
    @ Yoosef

    10 Years ago with my first attempt to build a SMPS, I built that circuit, and it worked fine, it was my first regulated SMPS.

    But I never completed a regulated SMPS, at least in the last year.

    But now I am moving to the new LLC SMPS topology.

    ======

    @ Silvio

    I had my ETD39 working fine with 20 Turns at primary. what core temperature you have in idle with your ETD39? at 28 Turns in primary?

    Maybe there is a reason?
    designing a good feedback is very complicated.
    for a good feedback we need to calculate poles/zeros/bode plots/phase margin/gain margin/transient response and other parameters.
    so i should use this present feedback.
    why you move to LLC SMPS ?
    i think for smps below 500 watt half bridge is the best choice.isn't that?

  3. #13
    .... Silvio's Avatar
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    @ MicrosiM

    Running at 2000 guass at 80Khz is rather a bit rough I guess. According to Excellent IT for ETD 39 it gives 25 turns for PC40 Material at 80Khz Max guass calculated at 1600

    My SMPS ETD39 Epcos N87

    Idle temperature at 30 turns primary and 240vac input was around 40 deg celcius after 30min operation at ambient temp 25 deg no cooling fan. My switching frequency was 65Khz.

    @ Yoosef
    I think that feedback arrangement is worth giving a try. If you have a better idea we will be happy to see your outcome
    Last edited by Silvio; 02-11-2019 at 08:37 PM.

  4. #14
    Quote Originally Posted by Silvio View Post
    @ MicrosiM

    Running at 2000 guass at 80Khz is rather a bit rough I guess. According to Excellent IT for ETD 39 it gives 25 turns for PC40 Material at 80Khz Max guass calculated at 1600

    My SMPS ETD39 Epcos N87

    Idle temperature at 30 turns primary and 240vac input was around 40 deg celcius after 30min operation at ambient temp 25 deg no cooling fan. My switching frequency was 65Khz.

    @ Yoosef
    I think that feedback arrangement is worth giving a try. If you have a better idea we will be happy to see your outcome
    best working temp for a pc40 core is about 90 deg because at this temp core losses is minimum
    so 60-80 deg is normal for ferrite core.
    in my smps with 19 turns in transformer primary core temp is about 50-55 deg without load at 27 deg ambient temp
    yeah i will try that feedback as soon as i purchase parts.

  5. #15
    Quote Originally Posted by yoosefheidar View Post
    best working temp for a pc40 core is about 90 deg because at this temp core losses is minimum
    so 60-80 deg is normal for ferrite core.
    in my smps with 19 turns in transformer primary core temp is about 50-55 deg without load at 27 deg ambient temp
    yeah i will try that feedback as soon as i purchase parts.
    Thats one very good reason why you get 50-55C in idle.
    www.diysmps.com & www.Micro-Audio.com

  6. #16
    Quote Originally Posted by Silvio View Post
    @ MicrosiM

    Running at 2000 guass at 80Khz is rather a bit rough I guess. According to Excellent IT for ETD 39 it gives 25 turns for PC40 Material at 80Khz Max guass calculated at 1600

    My SMPS ETD39 Epcos N87

    Idle temperature at 30 turns primary and 240vac input was around 40 deg celcius after 30min operation at ambient temp 25 deg no cooling fan. My switching frequency was 65Khz.

    @ Yoosef
    I think that feedback arrangement is worth giving a try. If you have a better idea we will be happy to see your outcome
    hi Silvio
    i use that feedback in my smps, but transformer sound become worse!(voltage changes become better and vary beetwen 92 to 94)
    listen to transformer sound in this link:
    https://vocaroo.com/i/s1mE8HRtrKuB
    Last edited by yoosefheidar; 02-12-2019 at 06:00 PM.

  7. #17
    .... Silvio's Avatar
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    So true such ticking sound. Did you try to put a minimum load? say 10 watts or a little more. It could be the case that the pulse width is very narrow. Take a shot across the trafo primary with the scope and see what it looks like. with and without load. Do you have a snubber across the primary or switching transistors. I also found out that the output diode will need a snubber when an output inductor is used, this causes a spike and reflects back in the primary winding

    In my case I found a balance between voltage drop from the inductor and regulation at load. My output inductor was 15uH the best compromise. The output capacitor was 4000uf per rail. The output 1000w
    Last edited by Silvio; 02-12-2019 at 06:47 PM.

  8. #18
    Quote Originally Posted by Silvio View Post
    So true such ticking sound. Did you try to put a minimum load? say 10 watts or a little more. It could be the case that the pulse width is very narrow. Take a shot across the trafo primary with the scope and see what it looks like. with and without load. Do you have a snubber across the primary or switching transistors. I also found out that the output diode will need a snubber when an output inductor is used, this causes a spike and reflects back in the primary winding

    In my case I found a balance between voltage drop from the inductor and regulation at load. My output inductor was 15uH the best compromise. The output capacitor was 4000uf per rail. The output 1000w
    i have two 5K resistor in output.it is about 0/5 watt.i didn't try smps with a load to check trafo sound.
    unfortunately i dont't have a scope and just use MATLAB for seeing wave forms.
    now duty cycle is about 35% and i don't think pulse width is narrow.
    i have a snubber in primary an one in secondary.but in secondary i have a resistor in series with capacitor beetwen positive and negative rail(center not included)

    so you think this sound is totally normal?is there any way to remove this sound in idle?whit my previous feedback i never had this sound just two ticking per second and not so loud.

  9. #19
    .... Silvio's Avatar
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    If output capacitor charges to full regulated voltage it will definitely have a narrow pulse due to it trying to keep the output regulated voltage. 5k resistor does not impose so much load for the pwm to keep the pulse width not so narrow, Why not try a lamp and load the output a bit to see if the ticking sound stops

  10. #20
    Quote Originally Posted by Silvio View Post
    If output capacitor charges to full regulated voltage it will definitely have a narrow pulse due to it trying to keep the output regulated voltage. 5k resistor does not impose so much load for the pwm to keep the pulse width not so narrow, Why not try a lamp and load the output a bit to see if the ticking sound stops
    i will try this to see what is result.
    why without feedback trafo don't have that sound at all?

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