A MOSFET rated for 15 A, carries a periodic current as shown in figure. The ON state resistance of the MOSFET is 0.15 Ω. The average ON state loss in the MOSFET is

• A. 15 W
• B. 33.8 W
• C. 7.5 W
• D. 3.8 W

Answer: (C)

Ip = 10 A
Ton = π
T = 2π

Iavg = Ip*√(Ton/T)
Iavg = 10*√(1/2)
= 7.07 A
The average ON state loss in MOSFET, P = Iavg²*R
P = 7.07²*0.15
P = 7.5 W