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Sg3525 pwm problem and changeover problem

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unelco

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sir,

I have a problem my converter board and ic used osilater ic sg3525.this circut pwm regulation not properly working and change over time output volt shoot what is the problem please help me
 

For us to help you, we would need you to upload a schematic. That would help us find out where the problem lies.
 

I'm assuming you use this board to drive MOSFETs.

In that case, remove R1 and connect pin 13 and pin 15 directly (short them). Place a 100nF (104) capacitor across C7. Change R18 and R19 to somewhere around 10Ω to 22Ω. Increase the value of the softstart capacitor C6 to around 4.7µF to 22µF. Remove R115 (47kΩ) and instead place a capacitor between pin 9 (COMP) and ground. Try with capacitors between 10nF and 100nF depending on how quickly you want the output to change (speed of output voltage correction).

I'm assuming C9 is 2.2µF (microFarads) and not 2.2mF (miliFarads). Increase the value to about 10µF to 22µF.

Try these changes and post the results.

Hope this helps.
Tahmid.
 

Sir,

Tanks for your replay . I am using this circut for ups aplication and i used resister R1 100E.Gate resister value 22E.but slow start capaciter value you advice 4.7uf to 22uf this value make slow stat mains to ups on changeover time
 

Ok. Try with something like 0.47uF to 1uF max then and see. If it's for UPS, keep the softstart capacitor small and make the other changes I suggested, especially the use of the capacitor in place of R115.
 
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    unelco

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sir,


thank you your valid replay,iam try this and replay next day
 

Sir,

sorry for the delay. I am trying your suggestion and some problem i remove the 9th pin to 1st pin connect resistor(R6) and load the ups the output is vibrating and a huge noice then i try solder the 47k resister(R6) 9th pin to 1st pin and try on ups no noice and smooth running any problem using this resister.I load the 750va ups connect output load 500w it is ok (out put volt 240v no load condition,210v out put volt 500w load condition).then i am trying to load in put mains.ups change manis mode then i switch of in put mains ups is change battery mode this time out put volt shooting 300v .I want change over time volt 240v not going output shooting . please help me
 

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Change R112 to 1k. Also try with 2.2k.
Replace C8 with a small value capacitor like 0.1uF.

Try this and let me know.

Hope this helps.
Tahmid.
 

Sir,

problem is solved i change the capaciter value ups is smooth working thanks for every thing.I send a scr charger circut . I have a problem this circut charging current limiting,i used copper shunt ,shunt leangth 13".please tell what is the actual problem
 

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  • CHARGER.pdf
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