* SPICE netlist
XU1 N016 N017 N017 N017 N019 N012 N014 N010 N006 N003 0 _RESET N007 N002 N001 N021 LTC2921 ;pnba V1)V2)V3)V4)S3)D3)S2)D2)S1)D1)Gnd)PG)Gate)Sense)Vcc)Timer
V1 N004 0 PULSE(0 5.5 10m 1m 1m 10 20)
V2 N013 0 PULSE(0 3.8 20m 1m 1m 10 20)
V3 N018 0 PULSE(0 2.8 27m 1m 1m 10 20)
MQ1 N002 N007 N003 N003 Si2316DS
R1 N002 N001 50m
C1 N007 0 .47
R2 N012 _RESET 4.7K
C2 N021 0 .22
R3 N011 N017 169K
R4 N017 0 49.9K
R5 N009 N016 243K
R6 N016 0 49.9K
R7 N001 N006 100
R8 N009 N014 100
R9 N011 N019 100
XU2 N001 N006 0 N008 N004 MP_01 MP_02 N004 LT1763-5 ;pnba OUT)Sense)GND)BYP)_SHDN)))IN
C3 N001 0 10
C4 N001 N008 .01
C5 N009 N015 .01
C6 N009 0 10
XU3 N009 N014 0 N015 N013 MP_03 MP_04 N013 LT1763-3.3 ;pnba OUT)Sense)GND)BYP)_SHDN)))IN
C7 N011 0 10
C8 N011 N020 .01
XU4 N011 N019 0 N020 N018 MP_05 MP_06 N018 LT1763-2.5 ;pnba OUT)Sense)GND)BYP)_SHDN)))IN
MQ2 N016 N022 0 0 BSS123
V4 N022 0 PULSE(0 5 2.5 100n 100n 200u 100)
Rload1 N012 0 70
C9 N003 0 10
C10 N010 0 10
C11 N012 0 10
V5 N005 0 PULSE(0 1 2 100n 100n 100u 100)
S1 0 N003 N005 0 SSHRT
MQ3 N009 N007 N010 N010 Si2316DS
MQ4 N011 N007 N012 N012 Si2316DS
Rload2 N010 0 70
Rload3 N003 0 70
.tran 4

* LTspice schematic (.asc)
Version 4
SHEET 1 3120 1344
WIRE -792 -656 -952 -656
WIRE -440 -656 -792 -656
WIRE -328 -656 -440 -656
WIRE 136 -656 -328 -656
WIRE 168 -656 136 -656
WIRE 264 -656 248 -656
WIRE 472 -656 264 -656
WIRE 824 -656 568 -656
WIRE 1096 -656 824 -656
WIRE 1224 -656 1096 -656
WIRE 1400 -656 1224 -656
WIRE -1512 -640 -1560 -640
WIRE -1272 -640 -1432 -640
WIRE -1240 -640 -1272 -640
WIRE -328 -640 -328 -656
WIRE 1096 -640 1096 -656
WIRE 1224 -640 1224 -656
WIRE 1400 -640 1400 -656
WIRE -440 -624 -440 -656
WIRE 1560 -624 1448 -624
WIRE 1560 -608 1560 -624
WIRE -728 -592 -952 -592
WIRE 552 -576 552 -608
WIRE 552 -576 408 -576
WIRE 1464 -576 1448 -576
WIRE -328 -560 -328 -576
WIRE -1272 -544 -1272 -640
WIRE -1240 -544 -1272 -544
WIRE 1096 -544 1096 -576
WIRE 1224 -544 1224 -560
WIRE 1400 -544 1400 -560
WIRE -904 -528 -952 -528
WIRE -792 -528 -792 -656
WIRE -792 -528 -840 -528
WIRE -728 -528 -728 -592
WIRE -440 -528 -440 -544
WIRE -440 -528 -728 -528
WIRE 1560 -512 1560 -528
WIRE -600 -496 -648 -496
WIRE -344 -496 -600 -496
WIRE 472 -496 -344 -496
WIRE 888 -496 568 -496
WIRE 1096 -496 888 -496
WIRE 1224 -496 1096 -496
WIRE 1096 -480 1096 -496
WIRE 1224 -480 1224 -496
WIRE -600 -464 -600 -496
WIRE -1096 -448 -1096 -480
WIRE 408 -416 408 -576
WIRE 552 -416 552 -448
WIRE 552 -416 408 -416
WIRE -600 -384 -600 -400
WIRE 1096 -384 1096 -416
WIRE 1224 -384 1224 -400
WIRE -504 -336 -568 -336
WIRE -120 -336 -504 -336
WIRE 472 -336 -120 -336
WIRE 728 -336 568 -336
WIRE 968 -336 728 -336
WIRE 1096 -336 968 -336
WIRE 1224 -336 1096 -336
WIRE 1224 -320 1224 -336
WIRE -504 -304 -504 -336
WIRE 1096 -304 1096 -336
WIRE -792 -288 -952 -288
WIRE -648 -288 -648 -496
WIRE -648 -288 -792 -288
WIRE -344 -288 -344 -496
WIRE -120 -288 -120 -336
WIRE -1512 -272 -1560 -272
WIRE -1272 -272 -1432 -272
WIRE -1240 -272 -1272 -272
WIRE -648 -256 -648 -288
WIRE 408 -256 408 -416
WIRE 552 -256 552 -288
WIRE 552 -256 408 -256
WIRE -728 -224 -952 -224
WIRE -504 -224 -504 -240
WIRE 1096 -208 1096 -240
WIRE 1224 -208 1224 -240
WIRE 136 -192 136 -656
WIRE 264 -192 264 -656
WIRE -1272 -176 -1272 -272
WIRE -1240 -176 -1272 -176
WIRE -904 -160 -952 -160
WIRE -792 -160 -792 -288
WIRE -792 -160 -840 -160
WIRE -728 -160 -728 -224
WIRE -648 -160 -648 -176
WIRE -648 -160 -728 -160
WIRE 728 -160 728 -336
WIRE -344 -96 -344 -208
WIRE -232 -96 -344 -96
WIRE 56 -96 -232 -96
WIRE 408 -96 408 -256
WIRE 408 -96 344 -96
WIRE -1096 -80 -1096 -112
WIRE 408 -64 408 -96
WIRE -120 -16 -120 -208
WIRE -8 -16 -120 -16
WIRE 56 -16 -8 -16
WIRE -344 0 -344 -96
WIRE -120 0 -120 -16
WIRE 408 16 408 0
WIRE -792 64 -952 64
WIRE -568 64 -568 -336
WIRE -568 64 -792 64
WIRE -8 64 -8 -16
WIRE 56 64 -8 64
WIRE -1512 80 -1560 80
WIRE -1272 80 -1432 80
WIRE -1240 80 -1272 80
WIRE -568 80 -568 64
WIRE -344 112 -344 80
WIRE -120 112 -120 80
WIRE -728 128 -952 128
WIRE -8 144 -8 64
WIRE 56 144 -8 144
WIRE 520 144 344 144
WIRE 728 144 728 -80
WIRE 728 144 520 144
WIRE -1272 176 -1272 80
WIRE -1240 176 -1272 176
WIRE -904 192 -952 192
WIRE -792 192 -792 64
WIRE -792 192 -840 192
WIRE -728 192 -728 128
WIRE -568 192 -568 160
WIRE -568 192 -728 192
WIRE -440 224 -440 -528
WIRE 56 224 -440 224
WIRE 824 224 824 -656
WIRE 824 224 344 224
WIRE -1096 272 -1096 240
WIRE -648 304 -648 -160
WIRE 56 304 -648 304
WIRE 888 304 888 -496
WIRE 888 304 344 304
WIRE -568 384 -568 192
WIRE 56 384 -568 384
WIRE 968 384 968 -336
WIRE 968 384 344 384
WIRE -232 464 -232 -96
WIRE 264 496 264 480
WIRE 136 528 136 480
WIRE -280 544 -696 544
WIRE -696 576 -696 544
WIRE -232 576 -232 560
WIRE 264 576 264 560
WIRE -696 672 -696 656
FLAG 1224 -544 0
FLAG 1400 -544 0
FLAG 1560 -512 0
FLAG 1464 -576 0
FLAG -1560 -272 0
FLAG -1560 80 0
FLAG 1224 -384 0
FLAG 1224 -208 0
FLAG -1560 -640 0
FLAG 408 16 0
FLAG 264 576 0
FLAG 136 528 0
FLAG -120 112 0
FLAG -344 112 0
FLAG -328 -560 0
FLAG -1096 -448 0
FLAG -1096 -80 0
FLAG -600 -384 0
FLAG -504 -224 0
FLAG -1096 272 0
FLAG 520 144 _RESET
FLAG -232 576 0
FLAG -696 672 0
FLAG 1096 -544 0
FLAG 1096 -384 0
FLAG 1096 -208 0
SYMBOL LTC2921 200 144 R0
SYMATTR InstName U1
SYMBOL voltage -1416 -640 R90
SYMATTR InstName V1
SYMATTR Value PULSE(0 5.5 10m 1m 1m 10 20)
SYMBOL voltage -1416 -272 R90
SYMATTR InstName V2
SYMATTR Value PULSE(0 3.8 20m 1m 1m 10 20)
SYMBOL voltage -1416 80 R90
SYMATTR InstName V3
SYMATTR Value PULSE(0 2.8 27m 1m 1m 10 20)
SYMBOL nmos 472 -608 R270
SYMATTR InstName Q1
SYMATTR Value Si2316DS
SYMBOL res 264 -672 R90
SYMATTR InstName R1
SYMATTR Value 50m
SYMBOL cap 392 -64 R0
SYMATTR InstName C1
SYMATTR Value .47
SYMBOL res 712 -176 R0
SYMATTR InstName R2
SYMATTR Value 4.7K
SYMBOL cap 248 496 R0
SYMATTR InstName C2
SYMATTR Value .22
SYMBOL res -136 -304 R0
SYMATTR InstName R3
SYMATTR Value 169K
SYMBOL res -136 -16 R0
SYMATTR InstName R4
SYMATTR Value 49.9K
SYMBOL res -360 -304 R0
SYMATTR InstName R5
SYMATTR Value 243K
SYMBOL res -360 -16 R0
SYMATTR InstName R6
SYMATTR Value 49.9K
SYMBOL res -456 -640 R0
SYMATTR InstName R7
SYMATTR Value 100
SYMBOL res -664 -272 R0
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res -584 64 R0
SYMATTR InstName R9
SYMATTR Value 100
SYMBOL PowerProducts\\LT1763-5 -1096 -592 R0
SYMATTR InstName U2
SYMBOL cap -344 -640 R0
SYMATTR InstName C3
SYMATTR Value 10
SYMBOL cap -840 -544 R90
SYMATTR InstName C4
SYMATTR Value .01
SYMBOL cap -840 -176 R90
SYMATTR InstName C5
SYMATTR Value .01
SYMBOL cap -616 -464 R0
SYMATTR InstName C6
SYMATTR Value 10
SYMBOL PowerProducts\\LT1763-3.3 -1096 -224 R0
SYMATTR InstName U3
SYMBOL cap -520 -304 R0
SYMATTR InstName C7
SYMATTR Value 10
SYMBOL cap -840 176 R90
SYMATTR InstName C8
SYMATTR Value .01
SYMBOL PowerProducts\\LT1763-2.5 -1096 128 R0
SYMATTR InstName U4
SYMBOL nmos -280 464 R0
SYMATTR InstName Q2
SYMATTR Value BSS123
SYMBOL voltage -696 560 R0
SYMATTR InstName V4
SYMATTR Value PULSE(0 5 2.5 100n 100n 200u 100)
SYMBOL res 1208 -336 R0
SYMATTR InstName Rload1
SYMATTR Value 70
SYMBOL cap 1080 -640 R0
SYMATTR InstName C9
SYMATTR Value 10
SYMBOL cap 1080 -480 R0
SYMATTR InstName C10
SYMATTR Value 10
SYMBOL cap 1080 -304 R0
SYMATTR InstName C11
SYMATTR Value 10
SYMBOL voltage 1560 -624 R0
SYMATTR InstName V5
SYMATTR Value PULSE(0 1 2 100n 100n 100u 100)
SYMBOL sw 1400 -544 R180
SYMATTR InstName S1
SYMATTR Value SSHRT
SYMBOL nmos 472 -448 R270
SYMATTR InstName Q3
SYMATTR Value Si2316DS
SYMBOL nmos 472 -288 R270
SYMATTR InstName Q4
SYMATTR Value Si2316DS
SYMBOL res 1208 -496 R0
SYMATTR InstName Rload2
SYMATTR Value 70
SYMBOL res 1208 -656 R0
SYMATTR InstName Rload3
SYMATTR Value 70