I'm looking into making a battery-powered USB charger and I kind of settled on a NCP1400A DC/DC converter. Bear in mind I have very little electronics knowledge. The documentation gives me suggestions on what external parts to use and I'm stuck on the inductor. I need to calculate Ipk (peak inductor current) but I need to know the value of Ton first. I assume it's referring to "on time". The doc doesn't mention "on time" and I have no idea how to calculate "on time". Can someone give me a clue?