Topswitch 262en DRAIN TO SOURCE waveform

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Hai ,
I designed flyback power supply 65v/3amps using Topswitch262EN . I got the output 65v stable . when i put the load 1amp it is ok but when i increase the load 2amps the output is going off that is thermal shutdown. i got the drain to source wave form .i am not understanding the wave form is it ok or not please tell me that drain to source wave form are ok or not and also tell me ic is not supporting 3amps . i will attach the waveforms and implemented board.

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Hai ,
I designed flyback power supply 65v/3amps using Topswitch262EN . I got the output 65v stable . when i put the load 1amp it is ok but when i increase the load 2amps the output is going off that is thermal shutdown. i got the drain to source wave form .i am not understanding the wave form is it ok or not please tell me that drain to source wave form are ok or not and also tell me ic is not supporting 3amps . i will attach the waveforms and implemented board.

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drain to source waveform .i am not understanding waveforms are correct or not pls explain

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in the image shows that ringing is more in mosfet drain node .please tell me how to reduce this ringing

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hai please replay me how to reduce the ringing in drain to source mosfet the above attached waveform shows the ringing . i used clamp diode p6ke200 but not reduced the ringing . transformer measurements as per the PI data sheet done .pls give me replay soon .

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Hi Kumar,

Thank you for choosing Power Integrations.

I would not recommend using a universal breadboard in doing a prototype especially for a 195W power supply. You will introduce a lot of parasitic and leakage components which is the reason for the ringing you are observing on your drain voltage waveform.

I suggest that you make a PCB layout design and fabricate a few samples for your prototype.

Do you also have a PIexpert design software file? I can help you check the design if you could provide your PIexpert file.

I agree with Mr Traveler, also the TOP-switch appears to have no heatsink? and the output diode appears to be a slow type?

Thanks for your replay . i am facing one more problem when i connected the output load 0.5 amps regulation is ok .more than 0.5amps regulation going to fail nearly 50% regulation fail. i used reference circuit from P.I 60v/3amps. and i connected control circuit (lm358) with the reference from der580 doc. for control circuit i gave 7volts dc externally from regulated power supply. with out load o/p is ok . i attached the schematic and transformer details.

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Thanks for your replay . i am facing one more problem when i connected the output load 0.5 amps regulation is ok .more than 0.5amps regulation going to fail nearly 50% regulation fail. i used reference circuit from P.I 60v/3amps. and i connected control circuit (lm358) with the reference from der580 doc. for control circuit i gave 7volts dc externally from regulated power supply. with out load o/p is ok . i attached the schematic and transformer details.

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New_WinRAR_ZIP_archive.zip398.09 KB

pls help me its so urjent for me to slove this problem

I doubt the TL431 can handle the 60V...

HI in my circuit clamp resistor is getting hot when i connect the load drain to source waveform peak is high nearly 150v peak is going .pls tell me how to slove this problem

where is your latest schematic? have you measured the leakage L of your Tx?

Thanks for your replay I am so bothered. i need to submit prototype .i am designing 60v/3amps as per the PI reference design i got stable output . but the problem is when i connect load more then 1amps drain waveform peak going high and more ringign . i have attached the schismatic and transformer details pls find the attachment . coming to transformer details which i got the values is leakage inductance 10uh, primary inductance is 139uh. pls help me

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TOPSwitch-HX_PIDesign1.pdf398.27 KB
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I am trying to implement one more design which is der580 59v/2amps . in that when i connect input voltage 51v i am getting 130v and high it is not stable isolating pls help me what is the problem. topswitch i used in this is top271eg pls confirm me can i use top271eg instead of top262en

Pls confirm me is that drain waveform is correct are not . tell me that waveform is in continuous mode or discontinuous mode .which one is more efficient

The TL431CLPM can only handle 36V MAXIMUM - your design is fatally flawed in this respect.