BUCK WITH RATIO CONVERTER -- STEP CHANGE IN LOAD (buckstep.cir)
**************** OUTPUT IS V(3) ***************************
**************** CIRCUIT PARAMETERS *******************
.PARAM VS=50
.PARAM L=1MH
.PARAM RL=0.4
.PARAM C=100UF
.PARAM RESR=0.5
.PARAM R=4
.PARAM D=.4
.PROBE
.TRAN 10uS 6MS UIC
**************** CIRCUIT DESCRIPTION ************
VS 1 0 {VS}
L 2 2a {L} IC=4.5
RL 2a 3 {RL}
C 3 3a {C} IC=18.2
RESR 3a 0 {RESR}
R 3 0 {R}
XSWITCH 1 0 2 PWM
********** AVERAGED SWITCH MODEL *******
.SUBCKT PWM A P C
GAP A X VALUE {D*I(VC)}  ; controlled current source Dic
ECP X P VALUE={D*V(A,P)} ; controlled voltage source Dvap
VC X C 0                 ; to measure ic for controlled current source
.ENDS
***************STEP CHANGE IN LOAD****************
RSTEP 5 0 4
SSTEP 3 5 20 0 SMOD
VCONT 20 0 PULSE(-1 1 2MS 1NS 1NS 10MS 20MS) ; change load resistance at 2ms
.MODEL SMOD VSWITCH(RON=.001 VON=.1 VOFF=-.1)
**************************************************
.END