* SPICE netlist
V1 N001 0 12
R1 N001 N004 100
V2 N006 0 PULSE(5 0 1n 5n 5n 4u)
R2 N001 N002 .1
XU1 N002 N006 N009 N012 0 N013 N010 N007 N001 N004 LT6109-2 ;pnba SenseLo)EN/_RST)OutC2)OutC1)V-)INC1)INC2)OutA)V+)SenseHi
MQ1 N003 N005 N002 N002 IRF9640
I1 N003 0 PWL(20u 0 40u 500m)
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 10
D1 N005 N001 BZX84C6V2L
D2 0 N003 1N914
MQ2 N011 N012 0 0 2N7002
.tran 60u

* LTspice schematic (.asc)
Version 4
SHEET 1 1360 640
WIRE 88 -320 -88 -320
WIRE 152 -320 88 -320
WIRE 280 -320 232 -320
WIRE 328 -320 280 -320
WIRE 376 -320 328 -320
WIRE 520 -320 472 -320
WIRE 680 -320 520 -320
WIRE 88 -304 88 -320
WIRE 520 -304 520 -320
WIRE 680 -304 680 -320
WIRE 328 -288 328 -320
WIRE 88 -208 88 -224
WIRE 520 -208 520 -240
WIRE 680 -208 680 -224
WIRE 328 -192 328 -224
WIRE -584 -160 -680 -160
WIRE -408 -160 -584 -160
WIRE -88 -160 -88 -320
WIRE -88 -160 -408 -160
WIRE -72 -160 -88 -160
WIRE 280 -160 280 -320
WIRE 280 -160 248 -160
WIRE -680 -144 -680 -160
WIRE -584 -144 -584 -160
WIRE -408 -144 -408 -160
WIRE -680 -48 -680 -64
WIRE -584 -48 -584 -80
WIRE -408 -48 -408 -64
WIRE -408 -48 -584 -48
WIRE -264 -48 -280 -48
WIRE -72 -48 -184 -48
WIRE 280 -48 248 -48
WIRE 280 -32 280 -48
WIRE -584 16 -584 -48
WIRE -408 16 -584 16
WIRE -408 32 -408 16
WIRE -200 64 -296 64
WIRE -168 64 -200 64
WIRE -72 64 -88 64
WIRE 280 64 280 48
WIRE 280 64 248 64
WIRE -296 80 -296 64
WIRE -200 80 -200 64
WIRE 280 80 280 64
WIRE -408 144 -408 112
WIRE -296 176 -296 160
WIRE -200 176 -200 160
WIRE -72 176 -200 176
WIRE 280 176 280 160
WIRE 280 176 248 176
WIRE 280 192 280 176
WIRE -200 224 -200 176
WIRE -200 224 -360 224
WIRE 88 240 88 224
WIRE -408 256 -408 240
WIRE 280 288 280 272
WIRE -584 320 -584 16
WIRE 392 320 392 -272
WIRE 392 320 -584 320
FLAG 88 240 0
FLAG -680 -48 0
FLAG -280 -48 0
FLAG 680 -208 0
FLAG 280 288 0
FLAG -408 256 0
FLAG -296 176 0
FLAG 520 -208 0
FLAG 328 -192 0
SYMBOL voltage -680 -160 R0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL res 72 -320 R0
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL voltage -168 -48 R90
SYMATTR InstName V2
SYMATTR Value PULSE(5 0 1n 5n 5n 4u)
SYMBOL res 136 -304 R270
SYMATTR InstName R2
SYMATTR Value .1
SYMBOL LT6109-2 88 0 R0
SYMATTR InstName U1
SYMBOL pmos 472 -272 M270
SYMATTR InstName Q1
SYMATTR Value IRF9640
SYMBOL current 680 -304 R0
SYMATTR InstName I1
SYMATTR Value PWL(20u 0 40u 500m)
SYMBOL res 264 -48 R0
SYMATTR InstName R3
SYMATTR Value 6.04K
SYMBOL res 264 64 R0
SYMATTR InstName R4
SYMATTR Value 2.37K
SYMBOL res 264 176 R0
SYMATTR InstName R5
SYMATTR Value 1.6K
SYMBOL res -424 -160 R0
SYMATTR InstName R6
SYMATTR Value 1K
SYMBOL voltage -296 64 R0
SYMATTR InstName V3
SYMATTR Value 3.3
SYMBOL res -216 64 R0
SYMATTR InstName R7
SYMATTR Value 10K
SYMBOL res -184 80 R270
SYMATTR InstName R8
SYMATTR Value 10K
SYMBOL res -424 16 R0
SYMATTR InstName R9
SYMATTR Value 1K
SYMBOL cap 312 -288 R0
SYMATTR InstName C1
SYMATTR Value 10
SYMBOL zener -600 -80 M180
SYMATTR InstName D1
SYMATTR Value BZX84C6V2L
SYMBOL diode 504 -240 M180
SYMATTR InstName D2
SYMATTR Value 1N914
SYMBOL nmos -360 144 M0
SYMATTR InstName Q2
SYMATTR Value 2N7002