LM2586: Transformer for LM2586

Jacopo Agostini

Intellectual 390 points

Part Number: LM2586

Hi,

I want to generate from a 24V input, a dual power supply, +-15V, with a maximum current of 0,2A on both output.

I have to use a flyback design so I choosed the LM2586 as controller for the transformer.

My question is: have you some advice about the transformer to use in this case for the flyback design?

I have found the transformer VPH4-0140-R from Coiltronics. Could it be the right one?

Thanks

Jacopo

over 7 years ago

0 Zack Liu over 7 years ago

TI__Mastermind 34231 points

Hi Jacopo,

What's the input voltage range? The peak current of transformer VPH4-0140-R is not big enough.
Please take a look at this transformer: www.coilcraft.com/.../lm258x.pdf

0 Jacopo Agostini over 7 years ago in reply to Zack Liu

Intellectual 390 points

Hi,

the input voltage is a fixed 24V.

Could I choose another transformer with an higher current limit like VPH5-0155-R?

In the coilcraft magnetics there is for example Q4343-BL that seems to be suitable for the applcation.

In particular I don't understand how I could find the maximum inductor current: is it like (N2/N1)*(Iout/(1-D)) + Iripple/2 ?

Regards
Jacopo

0 Zack Liu over 7 years ago in reply to Jacopo Agostini

TI__Mastermind 34231 points

Hi Jacopo,

You can use either Q4343-BL or Q4438-BL.
Because it would probably work at DCM, you cannot use this equation. I'd like to recommend you use a tool: www.ti.com/.../powerstage-designer

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LM2586: Transformer for LM2586