LM3481-Q1: Max duty cycle

Hi Alfie,

The device will work.

With dudy cycle of 0.85 in CCM mode, you will get only around 33.3V output.

You may get 40V with ducy cycle of 0.85 in DCM mode.

Best Regards,

Feng Ji

Hi Feng, customer design Vout=40V, when voltage supply start with Vin=7V, the output will rise and then decrease to 6.5V, look like the device turn off and Vout=Vin-Vdiode. but when power supply start with Vin=10V and then decrease Vin to 7V, the output voltage is 40V, it's normal.

Hi Feng, is there any excel table for calculate efficiency of LM3481? on customer case, the boost efficiency only have about 79~89% with 0-1A output current.

Hi Alfie,

Please attach the schematic.

Best Regards,

Feng Ji

Hi Alfie,

There are many factors that may affect the efficiency. You may try to use webench for efficiency reference.

Best Regards,

Feng Ji