Introduction to Electrical Power and Power Electronics

329Power Electronics Devices

The switching times come from the device vendor data sheet, whereas the switch-

ing frequency is set by the design engineer, and the switching power loss depends

on both.

Example 12.6

In the circuit below, the power electronics switch is operating at 1000-Hz switch-

ing frequency with a 60% duty ratio. The switch has on-state voltage drop of 1 V,

off-state leakage current of 1.5 mA in reverse bias, switch-on time of 1.2 μs, and

switch-off time of 1.5 μs. Determine the average power loss in the switch.

48 Vdc

10 Ω

Power

electronics

switch

I

Solution:

We use formulas developed in Section 12.6. One cycle takes 1/1000 = 0.00 ...