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275Conduction and Switching Losses

and above that, the curr

ent increases significantly. Either way, the switching

losses increase as we move away from D  0.5. Therefore, in general, we

must first examine the input range of our application, and see which of its ends

is furthest from D  0.5. For example, if in our application, the input range

corresponds to a duty cycle range of 0.6 to 0.8, we need to do the switching loss

calculation at D  0.8, that is, at V

INMIN

. However, if the duty cycle range is say,

0.2 to 0.7, we need to do the calculation at D  0.2, that is, at V

INMAX

.

8.13 How Switching Losses Vary ...