Version 4 SHEET 1 1416 680 WIRE -160 -336 -688 -336 WIRE 128 -336 -160 -336 WIRE 736 -336 128 -336 WIRE -160 -304 -160 -336 WIRE 128 -304 128 -336 WIRE -160 -208 -160 -240 WIRE 1040 -208 832 -208 WIRE 1152 -208 1104 -208 WIRE 1200 -208 1152 -208 WIRE 1264 -208 1200 -208 WIRE -496 -176 -576 -176 WIRE 128 -176 128 -224 WIRE 128 -176 -432 -176 WIRE 736 -176 736 -336 WIRE 832 -176 832 -208 WIRE 1264 -176 1264 -208 WIRE -576 -160 -576 -176 WIRE 1152 -160 1152 -208 WIRE 96 -112 32 -112 WIRE 128 -112 128 -176 WIRE 128 -112 96 -112 WIRE 208 -112 128 -112 WIRE 336 -112 288 -112 WIRE 512 -112 400 -112 WIRE 32 -96 32 -112 WIRE -576 -64 -576 -80 WIRE 832 -48 832 -96 WIRE 1152 -48 1152 -96 WIRE 1152 -48 832 -48 WIRE 1264 -48 1264 -96 WIRE 1264 -48 1152 -48 WIRE 32 -16 32 -32 WIRE 1152 -16 1152 -48 WIRE -208 0 -320 0 WIRE -320 48 -320 0 WIRE 736 80 736 -96 WIRE -688 128 -688 -336 WIRE 128 128 128 -112 WIRE 736 144 736 80 WIRE -320 160 -320 128 WIRE -256 160 -320 160 WIRE -160 160 -256 160 WIRE -48 160 -160 160 WIRE -16 160 -48 160 WIRE -256 176 -256 160 WIRE -160 192 -160 160 WIRE 320 224 272 224 WIRE 368 224 320 224 WIRE 528 224 368 224 WIRE 656 224 608 224 WIRE 688 224 656 224 WIRE 368 240 368 224 WIRE -256 272 -256 256 WIRE -160 272 -160 256 WIRE -160 272 -256 272 WIRE -48 272 -160 272 WIRE -16 272 -48 272 WIRE -48 320 -160 320 WIRE -16 320 -48 320 WIRE 368 320 368 304 WIRE -320 336 -320 160 WIRE -160 336 -160 320 WIRE 368 368 272 368 WIRE 416 368 368 368 WIRE 528 368 416 368 WIRE 656 368 608 368 WIRE 736 368 736 240 WIRE 736 368 656 368 WIRE 368 416 368 368 WIRE 736 416 736 368 WIRE -160 432 -160 416 WIRE -48 432 -160 432 WIRE -16 432 -48 432 WIRE -160 464 -160 432 WIRE -688 576 -688 208 WIRE -320 576 -320 416 WIRE -320 576 -688 576 WIRE -160 576 -160 528 WIRE -160 576 -320 576 WIRE 128 576 128 464 WIRE 128 576 -160 576 WIRE 368 576 368 480 WIRE 368 576 128 576 WIRE 736 576 736 496 WIRE 736 576 368 576 WIRE 128 592 128 576 FLAG 128 592 0 FLAG 368 320 0 FLAG -160 -208 0 FLAG 1152 -16 0 FLAG 1200 -208 out FLAG -208 0 out FLAG 32 -16 0 FLAG 512 -112 out FLAG -576 -64 0 FLAG 656 224 gate FLAG 656 368 sense FLAG 736 80 drain FLAG 96 -112 vcc FLAG -48 320 ref FLAG -48 432 osc FLAG -48 160 fb FLAG -48 272 cp FLAG 320 224 gdrive FLAG 416 368 sensef SYMBOL res -176 320 R0 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL res -336 32 R0 SYMATTR InstName R2 SYMATTR Value 18k SYMBOL res -336 320 R0 SYMATTR InstName R3 SYMATTR Value 4.7k SYMBOL res 624 352 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R4 SYMATTR Value 1k SYMBOL cap -176 464 R0 SYMATTR InstName C1 SYMATTR Value 4.7n SYMBOL cap -176 192 R0 WINDOW 3 59 32 Left 0 SYMATTR Value 100p SYMATTR InstName C2 SYMBOL res -272 160 R0 SYMATTR InstName R5 SYMATTR Value 150k SYMBOL res 720 400 R0 SYMATTR InstName R6 SYMATTR Value 1 SYMBOL cap 352 416 R0 SYMATTR InstName C3 SYMATTR Value 470p SYMBOL res 624 208 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R7 SYMATTR Value 22 SYMBOL schottky 384 304 R180 WINDOW 0 -29 63 Left 0 WINDOW 3 -75 7 Left 0 SYMATTR InstName D1 SYMATTR Value 1N5819 SYMATTR Description Diode SYMATTR Type diode SYMBOL res 112 -320 R0 SYMATTR InstName R8 SYMATTR Value 22k SYMBOL cap -176 -304 R0 WINDOW 39 39 36 Left 0 SYMATTR SpiceLine Rser=0.1 SYMATTR InstName C4 SYMATTR Value 220µ SYMBOL ind2 720 -192 R0 WINDOW 0 -36 29 Left 0 WINDOW 3 -44 82 Left 0 SYMATTR InstName L1 SYMATTR Value 1m SYMATTR Type ind SYMBOL ind2 848 -80 R180 WINDOW 0 -32 80 Left 0 WINDOW 3 -36 25 Left 0 SYMATTR InstName L2 SYMATTR Value 70µ SYMATTR Type ind SYMBOL schottky 1040 -192 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D4 SYMATTR Value MBR735 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1136 -160 R0 WINDOW 39 24 92 Left 0 SYMATTR SpiceLine Rser=10m SYMATTR InstName C7 SYMATTR Value 2200µ SYMBOL voltage -688 112 R0 WINDOW 123 0 0 Left 0 WINDOW 39 24 132 Left 0 SYMATTR SpiceLine Rser=1 SYMATTR InstName V1 SYMATTR Value 180 SYMBOL res 1248 -192 R0 SYMATTR InstName R9 SYMATTR Value 20 SYMBOL res 192 -96 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R10 SYMATTR Value 220 SYMBOL cap 16 -96 R0 SYMATTR InstName C5 SYMATTR Value 47µ SYMBOL diode 400 -128 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName D2 SYMBOL voltage -576 -176 R0 SYMATTR InstName V2 SYMATTR Value 8 SYMBOL diode -496 -160 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D3 SYMBOL nmos 688 144 R0 SYMATTR InstName M1 SYMATTR Value IRF840 SYMATTR Prefix X SYMBOL uc1843 128 288 R0 SYMATTR InstName U1 TEXT -664 -408 Left 0 !.tran 0 30m 0 1u startup TEXT -664 -440 Left 0 !.lib uc1843_lt.lib TEXT 768 -248 Left 0 !K L1 L2 1 TEXT 136 64 Left 0 ;Uth: 8V on, 6V off TEXT -584 -248 Left 0 ;quick start simulation TEXT -152 0 Left 0 ;feedback TEXT -664 -560 Left 0 ;This circuit has been posted sometime ago with an UC3842?.\nSo don't ask me whether it's correctly designed. TEXT 416 -136 Left 0 ;self power TEXT -664 -472 Left 0 !.lib irf_mosfet.lib TEXT 1152 -264 Left 0 ;Vnom = 12V TEXT -376 -408 Left 0 ;The simulation runs three times faster with trtol=7 and reltol=0.01 . TEXT -376 -472 Left 0 !.options reltol=0.01\n.options trtol=7 LINE Normal 128 -16 128 -16 2 LINE Normal -512 -336 -512 -336 2 LINE Normal -512 -336 -512 -336 2 LINE Normal -512 -336 -512 -336 2 RECTANGLE Normal 912 -16 656 -272 RECTANGLE Normal -352 -32 -624 -288 RECTANGLE Normal 793 -88 777 -184