I have tested a boost converter under different duty cycles. I know the voltage is related to the input voltage by V = Vin/(1-D) where D is the duty cycle. But for some reason, as I increase this duty cycle with my input voltage kept constant, the power efficiency of the converter goes down.
I am using a function generator to make the MOSFET switching, and a DC voltage supply for input. (something like this: http://shop.rabtron.co.za/catalog/bench-power-supply-c-46_374.html)
Can someone tell me why the power efficiency of a boost converter reduces as the duty cycle is increased?
EDIT: I put a circuit to make the question more clear. I actually did not bother to check the type of diode or MOSFET, and it seems like that would've been important…