* SPICE netlist
MQ1 N002 N005 N003 N003 Si4864DY
R1 N001 N002 5m
R2 N001 N007 34K
R3 N010 N007 1.74K
R4 N010 0 2.67K
R5 N003 N008 25.1K
R6 0 N008 3.57K
R7 N003 N011 24K
C1 N014 0 .068
C2 N015 0 .068
C3 N016 0 4
V1 N012 0 3.1
V2 N001 0 PWL(0 0 10u 0 100u 12 6 12)
C4 N003 0 2000
R8 0 N003 10
MQ2 N003 N006 N004 N004 Si4864DY
V3 N006 0 PWL(0 0 4 0 4.0001 12)
R9 N005 N009 10
R10 0 N004 .05
V4 N013 0 PWL(0 3.1 1 3.1 +100u 0)
XU1 N007 N010 N014 0 N012 N013 N016 N015 N011 N008 N003 N009 N002 N001 N001 LTC4215 uvautoretry=1 ovautoretry=1 ocautoretry=0 ;pnba UV)OV)SS)GND)ON)_EN)Timer)Vcc)GPIO1)FB)Source)Gate)Sense-)Sense+)Vdd
.tran 12

* LTspice schematic (.asc)
Version 4
SHEET 1 1952 528
WIRE -576 -264 -976 -264
WIRE -288 -264 -576 -264
WIRE -176 -264 -288 -264
WIRE -160 -264 -176 -264
WIRE -64 -264 -80 -264
WIRE -32 -264 -64 -264
WIRE 160 -264 64 -264
WIRE 384 -264 160 -264
WIRE 496 -264 384 -264
WIRE 592 -264 496 -264
WIRE 704 -264 592 -264
WIRE 784 -264 704 -264
WIRE 976 -264 880 -264
WIRE -976 -248 -976 -264
WIRE -576 -248 -576 -264
WIRE 592 -248 592 -264
WIRE 704 -248 704 -264
WIRE 976 -248 976 -264
WIRE 384 -216 384 -264
WIRE 48 -200 48 -216
WIRE 864 -168 864 -216
WIRE -976 -152 -976 -168
WIRE -576 -152 -576 -168
WIRE -464 -152 -576 -152
WIRE 496 -152 496 -264
WIRE 592 -152 592 -184
WIRE 704 -152 704 -168
WIRE 976 -152 976 -168
WIRE 384 -120 384 -136
WIRE 384 -120 320 -120
WIRE -576 -104 -576 -152
WIRE -288 -104 -288 -264
WIRE -176 -104 -176 -264
WIRE -64 -104 -64 -264
WIRE 48 -104 48 -120
WIRE 160 -104 160 -264
WIRE 384 -104 384 -120
WIRE 864 -72 864 -88
WIRE -464 -40 -464 -152
WIRE -384 -40 -464 -40
WIRE 320 -40 320 -120
WIRE 320 -40 272 -40
WIRE 384 -8 384 -24
WIRE -576 24 -576 -24
WIRE -384 24 -576 24
WIRE 496 24 496 -72
WIRE 496 24 272 24
WIRE -576 40 -576 24
WIRE -384 88 -448 88
WIRE 352 88 272 88
WIRE 352 104 352 88
WIRE -576 136 -576 120
WIRE -448 168 -448 88
WIRE -304 184 -304 168
WIRE 16 184 16 168
WIRE 176 184 176 168
WIRE -144 200 -144 168
WIRE 352 200 352 184
WIRE -448 264 -448 248
WIRE -304 264 -304 248
WIRE 16 264 16 248
WIRE 176 264 176 248
FLAG -576 136 0
FLAG -144 200 0
FLAG 384 -8 0
FLAG -304 264 0
FLAG 16 264 0
FLAG 176 264 0
FLAG -448 264 0
FLAG -976 -152 0
FLAG 592 -152 0
FLAG 704 -152 0
FLAG 976 -152 0
FLAG 864 -72 0
FLAG 352 200 0
SYMBOL nmos -32 -216 R270
SYMATTR InstName Q1
SYMATTR Value Si4864DY
SYMBOL res -176 -248 R270
SYMATTR InstName R1
SYMATTR Value 5m
SYMBOL res -592 -264 R0
SYMATTR InstName R2
SYMATTR Value 34K
SYMBOL res -592 -8 M180
SYMATTR InstName R3
SYMATTR Value 1.74K
SYMBOL res -592 24 R0
SYMATTR InstName R4
SYMATTR Value 2.67K
SYMBOL res 368 -232 R0
SYMATTR InstName R5
SYMATTR Value 25.1K
SYMBOL res 368 -8 M180
SYMATTR InstName R6
SYMATTR Value 3.57K
SYMBOL res 480 -168 R0
SYMATTR InstName R7
SYMATTR Value 24K
SYMBOL cap -320 184 R0
SYMATTR InstName C1
SYMATTR Value .068
SYMBOL cap 0 184 R0
SYMATTR InstName C2
SYMATTR Value .068
SYMBOL cap 160 184 R0
SYMATTR InstName C3
SYMATTR Value 4
SYMBOL voltage -448 152 R0
SYMATTR InstName V1
SYMATTR Value 3.1
SYMBOL voltage -976 -264 R0
SYMATTR InstName V2
SYMATTR Value PWL(0 0 10u 0 100u 12 6 12)
SYMBOL cap 576 -248 R0
SYMATTR InstName C4
SYMATTR Value 2000
SYMBOL res 688 -152 M180
SYMATTR InstName R8
SYMATTR Value 10
SYMBOL nmos 784 -216 R270
SYMATTR InstName Q2
SYMATTR Value Si4864DY
SYMBOL voltage 864 -184 R0
SYMATTR InstName V3
SYMATTR Value PWL(0 0 4 0 4.0001 12)
SYMBOL res 32 -216 R0
SYMATTR InstName R9
SYMATTR Value 10
SYMBOL res 960 -152 M180
SYMATTR InstName R10
SYMATTR Value .05
SYMBOL voltage 352 88 R0
SYMATTR InstName V4
SYMATTR Value PWL(0 3.1 1 3.1 +100u 0)
SYMBOL PowerProducts\\LTC4215-1 -64 24 R0
SYMATTR InstName U1