LM51231-Q1: LM51231-Q1

Nicola Giandomenico

Prodigy 10 points

Part Number: LM51231-Q1

Tool/software:

Dear Design support team,

I would like to know if it's possible to use the lm51231 as a negative output voltage.

In my design, I need to have a positive and a negative programmable output using the Vtrk input.

Thank you very much for your feedback.

Best Regards

4 months ago

0 Nicola Giandomenico 4 months ago

Prodigy 10 points

0 Nicola Giandomenico 4 months ago

Prodigy 10 points

Is this schematics correct ?

0 Moritz 4 months ago in reply to Nicola Giandomenico

TI__Genius 15575 points

Hi Nicola,

Thanks for reaching out.

It is possible to refer the IC to a negative voltage and boost from a negative input to a more negative output.

Please refer to this appnote: https://www.ti.com/lit/an/slvaf68/slvaf68.pdf

Best regards

Moritz

0 Nicola Giandomenico 4 months ago in reply to Moritz

Prodigy 10 points

Dear Moritz

Thank you very much for your answer.

Anyway, the LM51231 is a buck-boost converter. So do you have an application note for that kind of converter or have I correctly applied the modification showed in the annexed picture ?

Thabk you very much for your feed-back

Best Regards

0 Moritz 4 months ago in reply to Nicola Giandomenico

TI__Genius 15575 points

Hi Nicola,

LM51231 is a synchronous boost controller, it cannot do buck operation.

The schematic you attached is not correct. To make negative- to negative boost possible with using a boost controller, the ground level is floating and switching, like in the appnote i attached. In theory this could be done with LM51231 also. However, the use of ATRK would be difficult then, because it has to be referred to the switching GND.

I recommend to use a buck- controller instead for creating a negative to negative boost.

Please refer to the attached PDF and this appnote: https://www.ti.com/lit/an/slyt516/slyt516.pdf

Negative In to Negative Out power supplies.pdf

Best regards

Moritz

+1 Nicola Giandomenico 4 months ago in reply to Moritz

Prodigy 10 points

Hi Moritz, thank you for your answer. It helps me a lot.

Best Regards

Power management

Power management forum

LM51231-Q1: LM51231-Q1