SWITCHING LOSSES MODEL WITH ON/OFF SNUBBERS
* SWLOSSES.CIR
.PARAM T={0.00003}
Vb  3 0 PULSE(0A 5V 0s 2us 2us {T/3} {T}) ;Transistor base drive
Vd  1 0 DC 10V
Ld  1 5 0.5H IC=10A
D   5 1 DMOD
L1  5 2 0.5uH 
X1  2 3 0 XNPN
D1  2 4 DMOD
C1  4 3 5uF
R1  0 4 5ohm
.SUBCKT    XNPN       1       3       2   ; Home made NPN
*          name   collector  base  emitter
S1    1  6  5  2 SMOD
D1    6  2 DMOD
Rb    3  4 15ohm
Vb    4  2 DC 0V
RT    2  5 2ohm
CT    5  2 1uF
F1    2  5 POLY(1) Vb 0 50
.MODEL SMOD VSWITCH(Ron=0.10 Roff=100 Von=4V )
.MODEL DMOD D(Rs=0.01,Cjo=10e-09)
.ENDS XNPN
.MODEL DMOD D(Rs=0.01,Cjo=10e-09)
.TRAN 5us 0.1ms  UIC
.PROBE
.END