LM25149-Q1: maximum duty cycle

Hi Shinji,

The converter will go to duty cycle based on minimum off-time, 90ns.

Afterwards, the device will skip some off-time pulses to extend the duty cycle.

Up to 15 off-time pulses can be skipped, so the FSW can be divided by 16.

The maximum duty cycle can therefore be computed as [1 - (90ns*FSW/16)].

However if there is boot capacitor discharge and boot UVLO is hit, the number of skipped pulses will reduce, so the boot cap can recharge.

Hope this helps,

-Orlando