**Part Number:**LM5156

**Other Parts Discussed in Thread:**LM5155, , LM555

Hi,

I'm trying to design a boost converter to have 300VDC in the output from 12VDC (regulated) in the input, so I was thinking on using the switching controller LM5155/LM5156. For this purpose, I used the Excel file for the calculations and to reach this voltage, the duty cycle must be 96% which is out of the range for the calculations in the Excel but apparently is the upper limit for the LM5155/LM5156 from their datasheets.

My question is, could be working fine the LM5155/LM5156 at a 96% duty cycle? I did the calculations for a duty cycle of 95% and the voltage in the output would be 238V instead of 300V, which could be acceptable but not ideal.

Thank you and regards.