* SPICE netlist
V1 N006 0 5.236
V2 N009 0 5.236
V3 N010 0 3.536
V4 N011 0 3.536
V5 N013 0 3.236
V6 N014 0 3.236
XU13 N005 3.0V_Essential N004 0 N001 LT1017 ;pnba In+)In-)V+)V-)OUT
XU14 N005 3.0V_Essential N004 0 N002 LT1017 ;pnba In+)In-)V+)V-)OUT
XU15 N005 3.0V_Essential N004 0 N003 LT1017 ;pnba In+)In-)V+)V-)OUT
XU16 N005 3.0V_Essential N004 0 N001 LT1017 ;pnba In+)In-)V+)V-)OUT
XU17 N005 3.0V_Essential N004 0 N002 LT1017 ;pnba In+)In-)V+)V-)OUT
XU18 N005 3.0V_Essential N004 0 N003 LT1017 ;pnba In+)In-)V+)V-)OUT
V7 N004 0 7.4
R9 N004 N005 5000000
R10 N005 0 5000000
D1 N014 3.0V_Essential 1N5817
D2 N013 3.0V_Essential 1N5817
D3 N011 3.3V_Essential 1N5817
D4 N010 3.3V_Essential 1N5817
D5 N009 5V_Essential 1N5817
D6 N006 5V_Essential 1N5817
R28 0 N003 2Mega
R29 0 N002 2Mega
R30 0 N001 2Mega
R1 3.0V_Essential 0 10k
R2 3.3V_Essential 0 10k
R3 5V_Essential 0 10k
XU1 N008 N003 5V_Essential 0 N007 LT1017 ;pnba In+)In-)V+)V-)OUT
XU2 N008 N002 3.3V_Essential 0 N012 LT1017 ;pnba In+)In-)V+)V-)OUT
XU3 N008 N001 3.0V_Essential 0 N015 LT1017 ;pnba In+)In-)V+)V-)OUT
R4 3.0V_Essential N008 2Mega
R5 N008 0 1Mega
R6 N007 0 1Mega
R7 N012 0 2Mega
R8 N015 0 1.5Mega
.dc V7 7.4 6

* LTspice schematic (.asc)
Version 4
SHEET 1 1472 1600
WIRE 32 -800 -256 -800
WIRE 320 -800 32 -800
WIRE 48 -784 -240 -784
WIRE 256 -784 48 -784
WIRE 64 -768 -224 -768
WIRE 208 -768 64 -768
WIRE -320 -688 -624 -688
WIRE -144 -688 -320 -688
WIRE -80 -688 -144 -688
WIRE -320 -672 -320 -688
WIRE -80 -672 -80 -688
WIRE -624 -656 -624 -688
WIRE -512 -656 -624 -656
WIRE -352 -656 -368 -656
WIRE -112 -656 -128 -656
WIRE -512 -640 -512 -656
WIRE -256 -640 -256 -800
WIRE -256 -640 -288 -640
WIRE 32 -640 32 -800
WIRE 32 -640 -48 -640
WIRE -352 -624 -384 -624
WIRE -112 -624 -176 -624
WIRE -304 -608 -320 -608
WIRE -64 -608 -80 -608
WIRE -144 -592 -144 -688
WIRE -144 -592 -320 -592
WIRE -80 -592 -144 -592
WIRE -320 -576 -320 -592
WIRE -80 -576 -80 -592
WIRE -624 -560 -624 -656
WIRE -368 -560 -368 -656
WIRE -352 -560 -368 -560
WIRE -128 -560 -128 -656
WIRE -112 -560 -128 -560
WIRE -240 -544 -240 -784
WIRE -240 -544 -288 -544
WIRE 48 -544 48 -784
WIRE 48 -544 -48 -544
WIRE -512 -528 -512 -560
WIRE -384 -528 -384 -624
WIRE -384 -528 -512 -528
WIRE -352 -528 -384 -528
WIRE -176 -528 -176 -624
WIRE -112 -528 -176 -528
WIRE -512 -512 -512 -528
WIRE -304 -512 -320 -512
WIRE -64 -512 -80 -512
WIRE -144 -496 -144 -592
WIRE -144 -496 -320 -496
WIRE -80 -496 -144 -496
WIRE -320 -480 -320 -496
WIRE -80 -480 -80 -496
WIRE 736 -480 384 -480
WIRE -368 -464 -368 -560
WIRE -352 -464 -368 -464
WIRE -128 -464 -128 -560
WIRE -112 -464 -128 -464
WIRE 704 -464 464 -464
WIRE -224 -448 -224 -768
WIRE -224 -448 -288 -448
WIRE 64 -448 64 -768
WIRE 64 -448 -48 -448
WIRE 384 -448 384 -480
WIRE 464 -448 464 -464
WIRE 672 -448 544 -448
WIRE -384 -432 -384 -528
WIRE -352 -432 -384 -432
WIRE -176 -432 -176 -528
WIRE -112 -432 -176 -432
WIRE -304 -416 -320 -416
WIRE -64 -416 -80 -416
WIRE 672 -416 672 -448
WIRE 704 -416 704 -464
WIRE 736 -416 736 -480
WIRE -624 -384 -624 -480
WIRE -512 -384 -512 -432
WIRE -384 -384 -384 -432
WIRE -176 -384 -176 -432
WIRE -176 -384 -384 -384
WIRE 208 -368 208 -768
WIRE 208 -368 64 -368
WIRE 384 -368 208 -368
WIRE -368 -352 -368 -464
WIRE -128 -352 -128 -464
WIRE -128 -352 -368 -352
WIRE 256 -352 256 -784
WIRE 256 -352 48 -352
WIRE 464 -352 464 -368
WIRE 464 -352 256 -352
WIRE 320 -336 320 -800
WIRE 320 -336 32 -336
WIRE 544 -336 544 -368
WIRE 544 -336 320 -336
WIRE -656 -240 -688 -240
WIRE -272 -240 -576 -240
WIRE 112 -208 -288 -208
WIRE 64 -192 64 -368
WIRE 80 -192 64 -192
WIRE 272 -176 144 -176
WIRE 80 -160 16 -160
WIRE 272 -160 272 -176
WIRE -688 -128 -688 -240
WIRE -656 -128 -688 -128
WIRE -320 -128 -576 -128
WIRE 272 -64 272 -80
WIRE -688 -16 -688 -128
WIRE -656 -16 -688 -16
WIRE -384 -16 -576 -16
WIRE 112 64 -400 64
WIRE 48 80 48 -352
WIRE 80 80 48 80
WIRE -688 96 -688 -16
WIRE -656 96 -688 96
WIRE -432 96 -576 96
WIRE 272 96 144 96
WIRE 16 112 16 -160
WIRE 80 112 16 112
WIRE 272 112 272 96
WIRE -688 208 -688 96
WIRE -656 208 -688 208
WIRE -496 208 -576 208
WIRE 272 208 272 192
WIRE -688 320 -688 208
WIRE -656 320 -688 320
WIRE -544 320 -576 320
WIRE 112 320 -512 320
WIRE 32 336 32 -336
WIRE 80 336 32 336
WIRE 272 352 144 352
WIRE -688 368 -688 320
WIRE 16 368 16 112
WIRE 80 368 16 368
WIRE 272 368 272 352
WIRE -544 384 -544 320
WIRE -496 384 -496 208
WIRE -432 384 -432 96
WIRE -384 384 -384 -16
WIRE -320 384 -320 -128
WIRE -272 384 -272 -240
WIRE -544 464 -544 448
WIRE -512 464 -512 320
WIRE -512 464 -544 464
WIRE -496 464 -496 448
WIRE -496 464 -512 464
WIRE -432 464 -432 448
WIRE -400 464 -400 64
WIRE -400 464 -432 464
WIRE -384 464 -384 448
WIRE -384 464 -400 464
WIRE -320 464 -320 448
WIRE -288 464 -288 -208
WIRE -288 464 -320 464
WIRE -272 464 -272 448
WIRE -272 464 -288 464
WIRE 272 464 272 448
WIRE -496 480 -496 464
WIRE -496 480 -720 480
WIRE -128 480 -128 -352
WIRE -128 480 -496 480
WIRE -496 496 -496 480
WIRE -384 496 -384 464
WIRE -272 496 -272 464
WIRE -720 560 -720 480
WIRE -496 608 -496 576
WIRE -384 608 -384 576
WIRE -272 608 -272 576
WIRE -720 672 -720 640
WIRE 16 672 16 368
WIRE 16 672 -720 672
WIRE -720 688 -720 672
WIRE -720 800 -720 768
FLAG -688 368 0
FLAG -304 -608 0
FLAG -304 -512 0
FLAG -304 -416 0
FLAG -64 -416 0
FLAG -64 -512 0
FLAG -64 -608 0
FLAG -512 -384 0
FLAG -624 -384 0
FLAG 672 -416 0
FLAG 704 -416 0
FLAG 736 -416 0
FLAG -496 608 0
FLAG -384 608 0
FLAG -272 608 0
FLAG -272 496 5V_Essential
FLAG -384 496 3.3V_Essential
FLAG -496 496 3.0V_Essential
FLAG -720 800 0
FLAG 112 -144 0
FLAG 112 128 0
FLAG 112 384 0
FLAG 272 -64 0
FLAG 272 208 0
FLAG 272 464 0
SYMBOL voltage -560 -240 R90
SYMATTR InstName V1
SYMATTR Value 5.236
SYMBOL voltage -560 -128 R90
SYMATTR InstName V2
SYMATTR Value 5.236
SYMBOL voltage -560 -16 R90
SYMATTR InstName V3
SYMATTR Value 3.536
SYMBOL voltage -560 96 R90
SYMATTR InstName V4
SYMATTR Value 3.536
SYMBOL voltage -560 208 R90
SYMATTR InstName V5
SYMATTR Value 3.236
SYMBOL voltage -560 320 R90
SYMATTR InstName V6
SYMATTR Value 3.236
SYMBOL Comparators\\LT1017 -320 -640 R0
SYMATTR InstName U13
SYMBOL Comparators\\LT1017 -320 -544 R0
SYMATTR InstName U14
SYMBOL Comparators\\LT1017 -320 -448 R0
SYMATTR InstName U15
SYMBOL Comparators\\LT1017 -80 -640 R0
SYMATTR InstName U16
SYMBOL Comparators\\LT1017 -80 -544 R0
SYMATTR InstName U17
SYMBOL Comparators\\LT1017 -80 -448 R0
SYMATTR InstName U18
SYMBOL voltage -624 -576 R0
SYMATTR InstName V7
SYMATTR Value 7.4
SYMBOL res -528 -656 R0
SYMATTR InstName R9
SYMATTR Value 5000000
SYMBOL res -528 -528 R0
SYMATTR InstName R10
SYMATTR Value 5000000
SYMBOL schottky -560 384 R0
SYMATTR InstName D1
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky -512 384 R0
SYMATTR InstName D2
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky -448 384 R0
SYMATTR InstName D3
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky -400 384 R0
SYMATTR InstName D4
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky -336 384 R0
SYMATTR InstName D5
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky -288 384 R0
SYMATTR InstName D6
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 368 -464 R0
SYMATTR InstName R28
SYMATTR Value 2Mega
SYMBOL res 448 -464 R0
SYMATTR InstName R29
SYMATTR Value 2Mega
SYMBOL res 528 -464 R0
SYMATTR InstName R30
SYMATTR Value 2Mega
SYMBOL res -512 480 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res -400 480 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL res -288 480 R0
SYMATTR InstName R3
SYMATTR Value 10k
SYMBOL Comparators\\LT1017 112 -176 R0
SYMATTR InstName U1
SYMBOL Comparators\\LT1017 112 96 R0
SYMATTR InstName U2
SYMBOL Comparators\\LT1017 112 352 R0
SYMATTR InstName U3
SYMBOL res -736 544 R0
SYMATTR InstName R4
SYMATTR Value 2Mega
SYMBOL res -736 672 R0
SYMATTR InstName R5
SYMATTR Value 1Mega
SYMBOL res 256 -176 R0
SYMATTR InstName R6
SYMATTR Value 1Mega
SYMBOL res 256 96 R0
SYMATTR InstName R7
SYMATTR Value 2Mega
SYMBOL res 256 352 R0
SYMATTR InstName R8
SYMATTR Value 1.5Mega