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    tl431 and optocoupler feedback for sg35252

    can someone help me fine tune this circuit for feedback/error correction for sg3525 pushpulll configuration. i need to get the values of the resistor right. i dont want to use a transformer in between just want to sense the voltage directly.

    thanks

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    Re: tl431 and optocoupler feedback for sg35252

    any help from anybody?



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    Re: tl431 and optocoupler feedback for sg35252

    I can help but I could not open the file you posted
    I extracted your file. is it a Tinycad file?



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    Re: tl431 and optocoupler feedback for sg35252

    thanks picgak,

    just downloaded it now and it did open. u can use proteus to open it.

    i hav converted it to pdf

    thanks



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    Re: tl431 and optocoupler feedback for sg35252

    I have opened your circuit and made a slight change in it (see fig) so what is your required voltage at the output point which I marked as V



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    Re: tl431 and optocoupler feedback for sg35252

    thanks

    ok i want to use this as a feedback mechanism for sg3525 pwm inverter. so i wish to measure the output voltage directly (230v)

    thanks for your help



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    Re: tl431 and optocoupler feedback for sg35252

    use 56k for R2 and 2.2k variable as Rv1 give 2.5v as ref to pin2 of sg3525



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    Re: tl431 and optocoupler feedback for sg35252

    Quote Originally Posted by babatundeawe View Post
    i want to use this as a feedback mechanism for sg3525 pwm inverter. so i wish to measure the output voltage directly (230v)
    TL431
    Vka - 37V (MAX)
    In this scheme, it will burn.



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    Re: tl431 and optocoupler feedback for sg35252

    Quote Originally Posted by picgak View Post
    use 56k for R2 and 2.2k variable as Rv1 give 2.5v as ref to pin2 of sg3525
    ok i will give it a try and feed you back

    thanks



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    Re: tl431 and optocoupler feedback for sg35252

    Click image for larger version. 

Name:	TL431.png 
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Size:	78.2 KB 
ID:	87256

    +V1 <= Vka_max(37V)



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    Re: tl431 and optocoupler feedback for sg35252

    @pplus

    can u tell what u mean by Vka? is the cathode voltage of tl431 or that of the optocoupler?

    thanks



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    Re: tl431 and optocoupler feedback for sg35252

    it means maximum voltage the TL431 can withstand is 37v
    so +V1 marked in above circuit should not be above 37V



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    Re: tl431 and optocoupler feedback for sg35252

    ok guys i think ihave to order for another one cos i guess this one i have appears to be damaged due to high voltage.



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