Multi output regulation of flyback smps

cross regulation flyback

How can I regulate the all outputs of flyback smps.

I dont want to use linear regulator for seperated all outputs.

flyback cross regulation

i did not get you clearly
but you regulate the input of flyback and generate the multi output from flyback
you can even isolate the o/p from i/p
can you be more clear

bye
som

multi-output smps

bunalmis said:

How can I regulate the all outputs of flyback smps.

I dont want to use linear regulator for seperated all outputs.

Click to expand...

U can use without using linear regulator, simply put filter at output and then take feedback.. that will be sufficent...

flyback multi sortie

som_raparty is right the only way I know to do this is pre-regulate the Flybacks input.
Is there any reason you don’t want to use LDO’s at the o/p’s of your additional windings this is the most common method, and easier then cascading two SMP’s.

sivakumar_tumma said:

U can use without using linear regulator, simply put filter at output and then take feedback.. that will be sufficent...

Click to expand...

Can you explain this,I never heard of it. Take FB to where any controller only has one error amp for feedback.

flyback cross-regulation problem forum

I know the problem but I cannot solve !
It's here : I want some ( about four ) regulated voltages : +5V,-5V, +12V, -12V . It's OK when all output have not load. When one output have load, others outputs increase absolute value of voltage.
Why? I don' know why !

flyback multi output

This effect is called cross-regulation.
Normally only one output is regulated (the master) and the rest are just supposed to track. In a flyback the most you can hope for is about +/- 6% on the slaves, but more likely +/- 8%.
If better regulation than that is required, then you need to add post-regulators.

The causes for cross-regulation are: transformer leakage (less than ideal coupling), voltage drops in transformer windings and diode voltage drops which change with the load currents. All of these lead to poor cross-regulation.

Good transformer winding requires tight coupling between secondaries, but this is not easily achieved, especially if the number of secondaries is large.
Ensuring secondaries have low DC resistance is generally accomplished by using stranded wires, since you cannot just increase the diameter, given the high frequency.
To minimize rectifier drops you can use synchronous rectifiers, but that will add to the cost.