* SPICE netlist
V1 N001 0 PWL(0 0 4u 12)
R1 N001 N004 100
R2 N001 N002 .1
MQ1 N003 N005 N002 N002 IRF9640
R3 N007 N010 6.04K
R4 N010 N013 2.37K
R5 N013 0 1.6K
R6 N001 N005 1K
V3 N008 0 3.3
R7 N008 N012 10K
R8 N008 N009 10K
R9 N005 N011 1K
C1 N002 0 .1
D1 N005 N001 BZX84C6V2L
MQ2 N011 N012 0 0 2N7002
XU1 N002 N006 N009 N012 0 N013 N010 N007 N001 N004 LT6119-2 ;pnba SenseLo)LE)OutC2)OutC1)V-)INC1)INC2)OutA)V+)SenseHi
R10 N001 N006 24.9K
C2 N006 0 100n
I1 N003 0 PWL(0 0 515u 0 535u 500m) load
.tran 0 540u 500u

* LTspice schematic (.asc)
Version 4
SHEET 1 1440 640
WIRE 256 -320 80 -320
WIRE 320 -320 256 -320
WIRE 448 -320 400 -320
WIRE 496 -320 448 -320
WIRE 544 -320 496 -320
WIRE 720 -320 640 -320
WIRE 256 -304 256 -320
WIRE 720 -304 720 -320
WIRE 496 -288 496 -320
WIRE 256 -208 256 -224
WIRE 720 -208 720 -224
WIRE 496 -192 496 -224
WIRE -448 -160 -720 -160
WIRE -272 -160 -448 -160
WIRE -112 -160 -272 -160
WIRE 80 -160 80 -320
WIRE 80 -160 -112 -160
WIRE 96 -160 80 -160
WIRE 448 -160 448 -320
WIRE 448 -160 416 -160
WIRE -720 -144 -720 -160
WIRE -448 -144 -448 -160
WIRE -272 -144 -272 -160
WIRE -112 -144 -112 -160
WIRE -720 -48 -720 -64
WIRE -448 -48 -448 -80
WIRE -272 -48 -272 -64
WIRE -272 -48 -448 -48
WIRE -112 -48 -112 -64
WIRE 96 -48 -112 -48
WIRE 448 -48 416 -48
WIRE 448 -32 448 -48
WIRE -448 16 -448 -48
WIRE -272 16 -448 16
WIRE -272 32 -272 16
WIRE -112 32 -112 16
WIRE -64 64 -160 64
WIRE 0 64 -64 64
WIRE 96 64 80 64
WIRE 448 64 448 48
WIRE 448 64 416 64
WIRE -160 80 -160 64
WIRE -64 80 -64 64
WIRE 448 80 448 64
WIRE -272 144 -272 112
WIRE -160 176 -160 160
WIRE -64 176 -64 160
WIRE 96 176 -64 176
WIRE 448 176 448 160
WIRE 448 176 416 176
WIRE 448 192 448 176
WIRE -64 224 -64 176
WIRE -64 224 -224 224
WIRE 256 240 256 224
WIRE -272 256 -272 240
WIRE 448 288 448 272
WIRE -448 320 -448 16
WIRE 560 320 560 -272
WIRE 560 320 -448 320
FLAG 256 240 0
FLAG -720 -48 0
FLAG 720 -208 0
FLAG 448 288 0
FLAG -272 256 0
FLAG -160 176 0
FLAG 496 -192 0
FLAG -112 32 0
SYMBOL voltage -720 -160 R0
SYMATTR InstName V1
SYMATTR Value PWL(0 0 4u 12)
SYMBOL res 240 -320 R0
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL res 304 -304 R270
SYMATTR InstName R2
SYMATTR Value .1
SYMBOL pmos 640 -272 M270
SYMATTR InstName Q1
SYMATTR Value IRF9640
SYMBOL res 432 -48 R0
SYMATTR InstName R3
SYMATTR Value 6.04K
SYMBOL res 432 64 R0
SYMATTR InstName R4
SYMATTR Value 2.37K
SYMBOL res 432 176 R0
SYMATTR InstName R5
SYMATTR Value 1.6K
SYMBOL res -288 -160 R0
SYMATTR InstName R6
SYMATTR Value 1K
SYMBOL voltage -160 64 R0
SYMATTR InstName V3
SYMATTR Value 3.3
SYMBOL res -80 64 R0
SYMATTR InstName R7
SYMATTR Value 10K
SYMBOL res -16 80 R270
SYMATTR InstName R8
SYMATTR Value 10K
SYMBOL res -288 16 R0
SYMATTR InstName R9
SYMATTR Value 1K
SYMBOL cap 480 -288 R0
SYMATTR InstName C1
SYMATTR Value .1
SYMBOL zener -464 -80 M180
SYMATTR InstName D1
SYMATTR Value BZX84C6V2L
SYMBOL nmos -224 144 M0
SYMATTR InstName Q2
SYMATTR Value 2N7002
SYMBOL LT6119-2 256 0 R0
SYMATTR InstName U1
SYMBOL res -128 -160 R0
SYMATTR InstName R10
SYMATTR Value 24.9K
SYMBOL cap -128 -48 R0
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL current 720 -304 R0
SYMATTR SpiceLine load
SYMATTR InstName I1
SYMATTR Value PWL(0 0 515u 0 535u 500m)