1. Diode Switching Losses
Vin
Switching Power Pole
Switching Device
Iout

2. t Io Switching Device Behavior with Practical Diode:
Switch Turns “On”, Diode Turns “Off”
Switch Voltage (vDS)
Switch Current
Diode Current
Diode Voltage (rev)
vFM
Vin Io
IRRM
Vsat
IRRM t
-vFM ta
td(on) tb
tfv
tri
trr

3. DUON t Pd trr td(on) tc,on (Vin+ VFM )IRRM (Vin+ VFM )Io VFM Io
Switching Loss
On-State Diode Loss
VFM Io
On-State Switch Loss
Vsat Io
trr t
td(on)
tc,on

4. t Switching Device Behavior with Practical Diode:
Switch Turns “Off”, Diode Turns “On”
Switch Voltage (vDS)
Switch Current
Diode Current
Diode Voltage (rev)
Vin
vFM
Vsat Io
Vsat t
-vFM
td(off)
trv
tfi

5. DUOFF t Pd td(on) trv tfi tc,off (Vin+ VFM )Io Vsat Io VFM Io
Switching Loss
On-State Diode Loss
On-State Switch Loss
Vsat Io
VFM Io t
td(on)
trv
tfi
tc,off

6. Frequency Dependency: fs
Switching Loss
Frequency Dependency: fs
On-State Losses
Switch:
Diode:

7. Example 2.2 (…kinda) Vin = 40 v Io = 5 A fs = 200 kHz d = 0.3
tri = 15 ns
tfv = 15 ns
tc,on = 30 ns
trv = 20 ns
tfi = 15 ns
tc,off = 35 nS
VFM = 0.8 v
RDS,on = 25 mW
trr = 20 ns
IRRM = 2 A