WEBENCH® Tools/LM5005: Problems designing LM5005 as inverting Buck Boost

Hi, Marion,

The device can support this function, but Webench doesn't support simulation for this application. You can refer to the Webench schematic, and your board should work fine.

Hi Neal,

thank you for your reply. Is there another way to simulate this device?

The customer would need help tweaking the output capacitor to 33uH and wants to see how the device behaves.

Can you help?

Kind regards,

Marion

Neal, do you mind checking both designs for the following topics:

1. Design 29: what happens, if we put the output cap to 33uH

2. Design 23: if there is a different inductor than 87uH possible.

WBDesign29_LM5005_P12V_33uH_5x10uF.pdf

WBDesign23_LM5005_N12V.pdf

Neal, do you mind checking both designs for the following topics:

1. Design 29: what happens, if we put the output cap to 33uH

2. Design 23: if there is a different inductor than 87uH possible.

0434.WBDesign29_LM5005_P12V_33uH_5x10uF.pdf

0243.WBDesign23_LM5005_N12V.pdf

Hi, 

The webench can simulate the Buck configuration, like Design 29. I think increase output cap is fine. You can use Webench to simulate it.

For negative buck boost configuration, the webench can't change the inductance. If you want to simulate it, you can use Spice or TINA.

You can export Webench model to TINA, to get the IC model. Then you can configure it as buck boost.

https://www.ti.com/lit/mo/slvmay6a/slvmay6a.pdf

You can find the spice model here:

Hi Neal,

thank you for your answer.

I will check if it is possible for the customer to simulate it this way.

Kind regards,

Marion

Hello Neal,

since we have tried a lot with Webench already, the customer is not willing to try another simulation tool.

Can you help us find the right passives values for their requirements urgently?

I will write you privately as well.

Kind regards,

Marion