Hi there,
I'm working on a POL supply for a board which needs to be able to take a wide range input, 18 -60 V, and create a 5 and 15 volt rail. I'm thinking about using the LM5119 but I'd like to do some efficiency calculations first to determine the power dissipation of the regulator with the parts I've selected. I realise that the workbench calculator will do all this for you but I'd like to have a better understanding of where the numbers come from. So I have a couple of questions.
1) There is an internal regulator that uses Vin to create the bias rails for the gate drivers and to create a 0.8 V reference. How can I determine how much power these will draw from Vin at different frequencies and supply voltages?
2) I assume most of the logic will require fairly little power, at least that's what I gathered from the data sheet. So is the only other major component of the IC that will draw a substantial amount of power the gate driver? If so, how can I go about figuring out how much power they are using? If not, what other componenets whould I take into account?
I'm really just curious about how to go about figuring out how much power the actual IC will dissipate. After that I can figure out how much power the MOSFET's and inductors will use.
Anyway, it's my first kick at the can, so if anyone can help me here or point me in the way of some relevant documents or websites that would be greatly appreciated.
Thanks!
Graham
