Version 4
SHEET 1 2692 936
WIRE -80 -16 -128 -16
WIRE 128 -16 -80 -16
WIRE 800 -16 224 -16
WIRE 912 -16 800 -16
WIRE 1456 -16 1008 -16
WIRE 800 16 800 -16
WIRE 800 144 800 96
WIRE 928 144 928 32
WIRE 928 144 800 144
WIRE 928 176 928 144
WIRE 1152 176 928 176
WIRE -128 224 -128 -16
WIRE 1312 224 1248 224
WIRE 1376 224 1312 224
WIRE 1456 224 1456 -16
WIRE 1152 240 1152 176
WIRE 1376 240 1376 224
WIRE 928 256 928 176
WIRE 1248 256 1248 224
WIRE 1248 256 1200 256
WIRE 208 288 208 32
WIRE 1248 304 1200 304
WIRE 1248 336 1248 304
WIRE 1376 336 1376 320
WIRE 1376 336 1248 336
WIRE 1376 352 1376 336
WIRE 928 400 928 320
WIRE 432 464 400 464
WIRE 496 464 432 464
WIRE 544 464 496 464
WIRE 1456 464 1456 304
WIRE 1520 464 1456 464
WIRE 1648 464 1520 464
WIRE 1728 464 1648 464
WIRE 1808 464 1728 464
WIRE 544 480 544 464
WIRE 400 496 400 464
WIRE 496 496 496 464
WIRE 1456 496 1456 464
WIRE 928 512 928 464
WIRE 1648 560 1648 464
WIRE 1728 560 1728 464
WIRE 1808 576 1808 464
WIRE 400 592 400 576
WIRE 496 592 496 544
WIRE 496 592 400 592
WIRE 544 592 544 560
WIRE 736 592 544 592
WIRE 784 592 736 592
WIRE 880 592 784 592
WIRE 1328 592 1280 592
WIRE 1456 592 1456 576
WIRE 1456 592 1328 592
WIRE 736 608 736 592
WIRE 1456 608 1456 592
WIRE 1152 656 1152 320
WIRE 1392 656 1152 656
WIRE -128 752 -128 304
WIRE 208 752 208 368
WIRE 208 752 -128 752
WIRE 736 752 736 688
WIRE 736 752 208 752
WIRE 928 752 928 608
WIRE 928 752 736 752
WIRE 1456 752 1456 704
WIRE 1456 752 928 752
WIRE 1648 752 1648 624
WIRE 1648 752 1456 752
WIRE 1728 752 1728 640
WIRE 1728 752 1648 752
WIRE 1808 752 1808 640
WIRE 1808 752 1728 752
WIRE 1904 752 1808 752
WIRE -128 768 -128 752
WIRE 736 768 736 752
FLAG 736 768 0
FLAG 1376 352 0
FLAG 784 592 Port
FLAG -80 -16 VBat
FLAG 1520 464 VCC
FLAG 432 464 VCC
FLAG 1312 224 Switch
FLAG 1328 592 Read
SYMBOL sw 1152 336 R180
SYMATTR InstName S1
SYMATTR Value Switch
SYMBOL voltage 1376 224 R0
WINDOW 3 -383 392 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 2 5m 10u 10u 1m 20m 2)
SYMATTR InstName V1
SYMBOL voltage -128 208 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 9
SYMBOL res 1440 208 R0
SYMATTR InstName R1
SYMATTR Value 50
SYMBOL res 720 592 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL sw 544 576 M180
SYMATTR InstName S2
SYMATTR Value Switch
SYMBOL voltage 400 480 R0
WINDOW 3 -59 135 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR Value PULSE(0 2 6m 10u 10u 60m 100m 1)
SYMATTR InstName V3
SYMBOL zener 1664 624 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D3
SYMATTR Value 1N750
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1712 544 R0
SYMATTR InstName R5
SYMATTR Value 90
SYMBOL cap 1792 576 R0
SYMATTR InstName C1
SYMATTR Value 10µ
SYMBOL pmos 1008 32 M270
SYMATTR InstName M1
SYMATTR Value FDS4685
SYMBOL nmos 880 512 R0
SYMATTR InstName M2
SYMATTR Value BSS123
SYMBOL res 784 0 R0
SYMATTR InstName R3
SYMATTR Value 1Meg
SYMBOL pmos 128 32 R270
SYMATTR InstName M3
SYMATTR Value FDS4685
SYMBOL res 192 272 R0
SYMATTR InstName R6
SYMATTR Value 1Meg
SYMBOL npn 1392 608 R0
SYMATTR InstName Q1
SYMATTR Value BC547B
SYMBOL res 1440 480 R0
SYMATTR InstName R2
SYMATTR Value 50k
SYMBOL diode 912 400 R0
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL diode 912 256 R0
SYMATTR InstName D2
SYMATTR Value 1N4148
TEXT 1856 600 Left 2 ;Load
TEXT -160 792 Left 2 !.tran 100m uic
TEXT 112 784 Left 2 !.model Switch SW(Vt=1 Ron=1m Roff=100G)
TEXT 520 392 Left 2 ;Controller\nPort Pin
TEXT -64 256 Left 2 ;Battery
TEXT 1584 400 Left 2 ;5V\n"Regulator"
TEXT 1640 -16 Left 2 ;Notes:\nSecond Version with less components.\nTo keep the switch readable, D1 and D2 have been added\nand the switch goes to GND through Q1.\nR2 is the pullup of a Portpin.\nCan use a changeover switch to provide input.\nV1 simulates the Key as it is pressed by the user.\nV3 simulates the portpin that tries to keep the cirquit 'on'.\nBattery voltage must be high enough to turn on the switch M1.\nM3 is for reverse polarity protection.