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LM5155-Q1: Maximum boost ratio as Sepic topo

Part Number: LM5155-Q1
Other Parts Discussed in Thread: LM5155

Hello team,

I need to check what is the highest boost ratio when use LM5155 as Sepic topo.

In the datasheet, when RT=220k, 

if Dmax=90% (min), the boost ratio is 9,

if Dmax=93% (typical), the boost ratio is 13.3,

if Dmax=94% (max), the boost ratio is 24.

The boost ratio range greatly under different Dmax value, so they want to confirm is it safe to continues work under boost ratio=24 when power is about 15-20W, and what is the recommended maximum boost ratio?


  • Hi Daniel,

    Generally, we should try to avoid working close to max duty cycle. Very high duty cycle will lead to low efficiency.

    Can you share more information about your application? Such as Vin, Vout, Iout.

    Best Regards,