flyback converter current

my flyback converter I input 3 ,2 A and I output 1 ,5 A,
what cause it???

i using flyback converter conduction continous mode..with f 20 khz..

please help??

Missing all important details about your flyback converter…

1.

If it's a flyback type then you have a transformer in the output stage.

It must be a step-down transformer, right?

With a diode in series? That will create a fraction of a volt drop.

2.

A transformer only conveys AC to the secondary.

So when you say continuous conduction mode, do you mean the transformer primary receives AC with a continual DC component?

Then this is inefficient use of the transformer. Only the AC component will transfer any power.

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Edit: Reading an article I see there is such a thing as using continuous mode in a flyback converter. Unexpected.

I was going to mention that your transformer might be saturating, but I suppose you selected one which can handle the currents you are sending through it, at your stated frequency of 20 kHz.

Dear Pol
Hi
How much is your input voltage and of course out put voltage before your filter ?
Best Wishes
Goldsmith

i have done the flyback converter,,
but i dont know how to make the current limiter, any one can help me???

please......

Hi pol
It is simple . but it depends on that what topology you have used for ? e.g current mode or voltage mode ? and also it depends on what driver IC you have used ? if you tell me more informations i can help you as well .
Best Wishes
Goldsmith

Post #2 still holds.

i using the flyback topology,
i use ic sg3524,
now i use voltage mode....

help me please...

Hi pol
Well it has a pin that called i sense . if you read it's datasheet it gave you the manner for current limiting as well . but if you need variable current you will need an opamp and then a reference voltage that can be variable .
Good luck
Goldsmith

how to make the current limiter depends on datasheet i'm confused,???

Hi pol
What i have told ? i have told that there is two pin that called isense . did you see that ? an important think is how to read a datasheet carefully . no problem ! see below , please :

Good luck
Goldsmith

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Pol , of course there are many other manners available for this aim . but it depends on you ! for example if your IC had not any pin for current limiting do you know what you could do ? it is simple ! breaking the voltage feedback pin !!