LM5022: Sepic Mode & Boost Mode

Thorsten Bursche

Part Number: LM5022

Hi, everybody,
I have a basic question about the LM5022. We want to use it for Boost and Sepic Mode. Input voltage should be 10V-28V and 24V output. Up to VIN = 24V everything is good, from 24V on the voltage increases with respect to VIN.

Many Thanks.

Greets

Thorsten

over 5 years ago

0 Richard Fu22 over 5 years ago

TI__Mastermind 31105 points

Hi Thorsten,

Can you clarify what you mean by SEPIC and Boost mode? The schematic you've shown is a boost topology. In this case, this is expected, since in a boost topology, there is a high-side path from the input to output. If your input is higher than the output regulation target, the output will rise with input minus a diode drop.

Thanks,

Richard

0 Thorsten Bursche over 5 years ago in reply to Richard Fu22

Prodigy 80 points

Hi Richard,

I would use the LM5022 as boost and sepic controller. The input voltage is between 10V and 28V and should always be 24V. Can I achieve this by changing the circuitry or do I have to use a different regulator?

Greets,

Thorsten

0 Richard Fu22 over 5 years ago in reply to Thorsten Bursche

TI__Mastermind 31105 points

Hi Thorsten,

In this case, you will need to change the circuit topology to be a SEPIC, which will boost your low input to 24V, and buck your high input to 24V as well.

I recommend looking at this thread for more information on designing a SEPIC converter.

https://e2e.ti.com/support/power-management/f/196/t/764027?LM5022-LM5155-How-to-evaluate-design-and-fine-tune-a-SEPIC-topology-

Thanks,

Richard

0 Thorsten Bursche over 5 years ago in reply to Richard Fu22

Prodigy 80 points

Hi, Richard,
thanks for your feedback. I'll look into it.
Greetings
Thorsten

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LM5022: Sepic Mode & Boost Mode