LM5019 want to run LM5019ISOEVAL isolated ref design in Webench

George Biner (Arrow)

Other Parts Discussed in Thread: LM5019, LM5019ISOEVAL, LM5018

Hello: I have an inquiry from my customer:

>>>>>> I have the LM5019ISOEVAL EVM. I'd like to know if webench supports running the reference design schematic (using a coupled inductor as an isolation transformer like what is done on the reference design)? I would like to use the coilcraft LPD3015 series inductor if possible (http://www.coilcraft.com/lpd3015.cfm). We need to be able to fit this circuit under 2.8mm tall. The LM5019 uses a LPD5030, which is 3.0mm tall (too tall). I would like to put the LPD3015 series inductor into the webench simulation of the LM5019 ref design, but I can't find that isolated supply reference supply in webench. Any issues with dropping the LPD3015 coupled inductor into the LM5019 ref design circuit in place of the LPD5030? >>>>>>>

EAU is 5k. Thanks. George Biner, FAE Arrow LA

over 12 years ago

0 Vijay86929 over 12 years ago

TI__Genius 11490 points

Hi George,

What is the output current you need? Some other low profile options are:

LPD3015 0.39 - 330 µH, up to 3.4 A
LPD4012 0.33 - 330 µH, up to 5.6 A
LPD5010 0.68 - 220 µH, up to 2.8 A

0 Troy Hawkins over 12 years ago in reply to Vijay86929

Ideally it would have an output of 3.3V at 30mA. The output is only driving an LED so the output voltage is not critical (as long as it is greater than 2V forward bias of the LED) and the current is just to drive the LED (<30mA). Is it sufficient to take the LM5019 reference design circuit and swap out the LPD5030 series inductor for the same inductance LPD3015 version? Ideally I would be able to model this in Webench. Is a model of the reference design circuit.

Is the LM5019 reference design circuit available in Webench to simulate?

0 George Biner (Arrow) over 12 years ago in reply to Troy Hawkins

Intellectual 705 points

Hello: can someone respond on this? thanks. G Biner, Arrow LA

0 Troy Hawkins over 12 years ago in reply to Troy Hawkins

Another question. Can I assume D2 is not necessary if the output voltage is set for a lower voltage than the VCC that LM5019 puts out? For instance if R4/R5 are adjusted such that the output is 3.3V (instead of the 10V normally created by the ref design), then the D2 is never forward biased and does not serve a purpose. Is this correct? Can this component be removed?

0 Vijay86929 over 12 years ago in reply to Troy Hawkins

TI__Genius 11490 points

The buck design circuit is availabe in webench. The isolated reference design, unfortunately, is not in webench yet.

Regards,

Vijay

0 Vijay86929 over 12 years ago in reply to Troy Hawkins

TI__Genius 11490 points

Yes, D2 can be removed. It is not essential for circuit operation.

Regards,

0 Amita JIndal over 12 years ago in reply to Vijay86929

Prodigy 80 points

Hi Vijay,

I am planning to use LM5018 for an on-board power supply design. But the transformer I want to use with it has very low primary inductance 3.8uH. Do you know what 3 secondary winding transformer would be suitable for this IC? or can you recommend another IC with lower primary inductance requirement but all the other specs same as LM5018.

Thanks.

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LM5019 want to run LM5019ISOEVAL isolated ref design in Webench