Version 4
SHEET 1 1580 680
WIRE 112 32 64 32
WIRE 240 32 112 32
WIRE 448 32 320 32
WIRE 560 32 448 32
WIRE 752 32 624 32
WIRE 864 32 752 32
WIRE 912 32 864 32
WIRE 1168 32 1168 0
WIRE 448 80 448 32
WIRE 752 80 752 32
WIRE 912 80 912 32
WIRE 1168 80 1168 32
WIRE 64 128 64 32
WIRE 400 160 352 160
WIRE 1168 192 1168 160
WIRE 448 224 448 176
WIRE 752 224 752 144
WIRE 912 224 912 160
WIRE 64 240 64 208
FLAG 64 240 0
FLAG 448 224 0
FLAG 752 224 0
FLAG 912 224 0
FLAG 864 32 OUT
FLAG 112 32 IN
FLAG 1168 192 0
FLAG 1168 32 PWM
FLAG 352 160 PWM
SYMBOL voltage 64 112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value {Vin}
SYMBOL ind 224 48 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 5 56 VBottom 2
SYMATTR InstName L1
SYMATTR Value 20µ
SYMBOL cap 736 80 R0
SYMATTR InstName C1
SYMATTR Value 47µ
SYMATTR SpiceLine Rser=0.022
SYMBOL res 896 64 R0
SYMATTR InstName R1
SYMATTR Value 12
SYMBOL voltage 1168 64 R0
WINDOW 0 -61 16 Left 2
WINDOW 3 -154 160 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 15 0 1n 1n {D} {1/F})
SYMBOL schottky 560 48 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value MBRS360
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL nmos 400 80 R0
SYMATTR InstName M1
SYMATTR Value SUD40N04-10A
TEXT 376 312 Left 2 !.tran 0 7m 0 10n
TEXT 504 -144 Left 2 !.PARAM F = 300k
TEXT 504 -112 Left 2 !.PARAM D = (1 - Vin / Vout) * (1/F)
TEXT 504 -200 Left 2 !.PARAM Vin = 5V
TEXT 504 -176 Left 2 !.PARAM Vout = 12V