Flyback Regulator Transformers

I have always tried to keep away from components such as inductors and transformers... the whole aspect of make it yourself puts me off.

Anyhow, I am building a Flyback Regulator to power some simple electronics in my car. Input voltages (9-16) Output should be fixed to 12V.

I want to use the LM2587-12T Flyback Regulator (Figure 9 in the datasheet)... This however requires an external transformer with a 1:1 turns ratio and 22uH inductance.

How do I make this? or please tell me it can be bought.

Thanks
StudentSA

Digi-Key - 513-1033-1-ND (Manufacturer - CTX33-2P-R)

https://www.electro-tech-online.com/custompdfs/2010/05/38084bfd-81fb-4278-b044-dd8c9988c924.pdf

I guess it would work fine if the inductance is not exactly 22µH. Does datasheet say anything about that?

OK… how much power do you need? BTW- in a flyback the “transformer” is not a transformer, it’s a coupled inductor. If you are building fig 4 or fig 9 from the datasheet, on page 16 it lists part numbers. If you want to wind it yourself, you will need a gapped core. The output power will determine how big of a core you will need.

Grossel said:

I guess it would work fine if the inductance is not exactly 22µH. Does datasheet say anything about that?

Click to expand...

in general the number should be considered a minimum, within reason. increasing to much will limit power and decreasing to much will increase ripple and potentially saturate the inductor.

Im designing for 1A maximum...

I only have RS Components as a supplier, they have inductors with 3 windings on each side of the core, these come in 21.6uH per coil I think
https://www.electro-tech-online.com/custompdfs/2010/05/0900766b80649d7c.pdf

However would it work if I bought a 10.9uH per coil
https://www.electro-tech-online.com/custompdfs/2010/05/0900766b80649931.pdf
and if I joined in series coil 1 and 2 for example?

Sorry please remember I new with inductors and transformers

StudentSA said:

Im designing for 1A maximum...

I only have RS Components as a supplier, they have inductors with 3 windings on each side of the core, these come in 21.6uH per coil I think
https://www.electro-tech-online.com/custompdfs/2010/05/0900766b80649d7c-1.pdf

However would it work if I bought a 10.9uH per coil
https://www.electro-tech-online.com/custompdfs/2010/05/0900766b80649931-1.pdf
and if I joined in series coil 1 and 2 for example?

Sorry please remember I new with inductors and transformers

Click to expand...

sorry i goofed. those are actually not enough unless you are running continuous instead of discontinuous. you need to be able to support the peak current with out saturating. other than than that you just parallel the windings.