Version 4 SHEET 1 1224 1368 WIRE -816 80 -1632 80 WIRE -608 80 -816 80 WIRE 304 176 240 176 WIRE 528 176 384 176 WIRE -1632 288 -1632 80 WIRE -1568 288 -1632 288 WIRE -1280 288 -1568 288 WIRE -1136 288 -1280 288 WIRE -1088 288 -1136 288 WIRE -944 288 -1008 288 WIRE -896 288 -944 288 WIRE 96 288 -896 288 WIRE 240 288 240 176 WIRE 240 288 96 288 WIRE 304 288 240 288 WIRE 416 288 400 288 WIRE 528 288 528 176 WIRE 528 288 496 288 WIRE 624 288 528 288 WIRE 688 288 624 288 WIRE -608 304 -608 80 WIRE -1280 336 -1280 288 WIRE -1136 336 -1136 288 WIRE -944 336 -944 288 WIRE 96 368 96 288 WIRE -816 416 -816 80 WIRE -400 416 -816 416 WIRE -192 416 -400 416 WIRE -1136 448 -1136 416 WIRE -992 448 -1136 448 WIRE -1136 480 -1136 448 WIRE -400 480 -400 416 WIRE -608 496 -608 384 WIRE -544 496 -608 496 WIRE -432 496 -544 496 WIRE 96 512 96 448 WIRE 96 512 -368 512 WIRE 144 512 96 512 WIRE 320 512 320 336 WIRE 320 512 144 512 WIRE -432 528 -512 528 WIRE 624 576 624 288 WIRE 624 576 -16 576 WIRE -1280 608 -1280 416 WIRE -1216 608 -1280 608 WIRE -1136 608 -1136 560 WIRE -1136 608 -1216 608 WIRE -1216 640 -1216 608 WIRE -512 640 -512 528 WIRE 96 640 -512 640 WIRE 528 640 528 288 WIRE 624 752 624 576 WIRE -816 784 -816 416 WIRE -992 800 -992 448 WIRE -896 800 -992 800 WIRE -848 800 -896 800 WIRE -608 816 -608 496 WIRE -608 816 -784 816 WIRE -944 832 -944 416 WIRE -896 832 -944 832 WIRE -848 832 -896 832 WIRE -192 880 -192 416 WIRE -112 896 -160 896 WIRE 96 896 96 640 WIRE 96 896 -112 896 WIRE 320 896 320 512 WIRE -608 912 -608 816 WIRE -224 912 -608 912 WIRE -1632 928 -1632 288 WIRE -112 928 -160 928 WIRE -16 928 -16 576 WIRE -16 928 -112 928 WIRE 96 992 96 896 WIRE -1632 1152 -1632 1008 WIRE -1216 1152 -1216 720 WIRE -1216 1152 -1632 1152 WIRE -816 1152 -816 848 WIRE -816 1152 -1216 1152 WIRE -400 1152 -400 544 WIRE -400 1152 -816 1152 WIRE -192 1152 -192 944 WIRE -192 1152 -400 1152 WIRE 96 1152 96 1072 WIRE 96 1152 -192 1152 WIRE 320 1152 320 960 WIRE 320 1152 96 1152 WIRE 528 1152 528 704 WIRE 528 1152 320 1152 WIRE 624 1152 624 832 WIRE 624 1152 528 1152 WIRE -1632 1184 -1632 1152 FLAG -1632 1184 0 FLAG 688 288 OUT IOPIN 688 288 Out FLAG -1568 288 SUPPLY FLAG -896 800 Ithr FLAG -896 832 Imon FLAG -896 288 Vm FLAG 144 512 M1G FLAG -544 496 U1orU2 FLAG -112 896 Vthr FLAG -112 928 Vmon SYMBOL voltage -1632 912 R0 WINDOW 123 24 132 Left 0 WINDOW 39 0 0 Left 0 WINDOW 3 40 -19 Left 0 SYMATTR InstName V1 SYMATTR Value SINE(18VDC 0.0 1KHz) SYMBOL res 608 736 R0 SYMATTR InstName Rload SYMATTR Value 1 SYMBOL voltage -1280 320 R0 WINDOW 123 24 132 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 2.5V SYMBOL res -1152 320 R0 SYMATTR InstName R1 SYMATTR Value 90.9 SYMBOL res -1152 464 R0 SYMATTR InstName R2 SYMATTR Value 2939 SYMBOL res -1232 624 R0 SYMATTR InstName R3 SYMATTR Value 5487 SYMBOL res -1104 304 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R4 SYMATTR Value 0.5 SYMBOL res -928 432 R180 WINDOW 0 36 76 Left 0 WINDOW 3 36 40 Left 0 SYMATTR InstName R5 SYMATTR Value 90.9 SYMBOL Opamps\\opamp2 -816 752 R0 SYMATTR InstName U1 SYMATTR Value LM139 SYMBOL cap 512 640 R0 SYMATTR InstName C2 SYMATTR Value 20µF SYMBOL res 400 304 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName R11 SYMATTR Value 1K SYMBOL res 80 352 R0 SYMATTR InstName R12 SYMATTR Value 100K SYMBOL cap 304 896 R0 SYMATTR InstName C3 SYMATTR Value 0.1µF SYMBOL Opamps\\opamp2 -192 848 M0 SYMATTR InstName U2 SYMATTR Value LM139 SYMBOL voltage 96 976 R0 WINDOW 123 24 132 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 1.5V SYMBOL Opamps\\opamp2 -400 448 R0 SYMATTR InstName U3 SYMATTR Value LM139 SYMBOL res -624 288 R0 SYMATTR InstName R6 SYMATTR Value 100K SYMBOL pmos 400 336 M270 WINDOW 0 97 75 VLeft 0 WINDOW 3 70 74 VLeft 0 SYMATTR InstName M1 SYMATTR Value FDS4685 SYMBOL res 288 192 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName Rfold SYMATTR Value 1800 TEXT -592 112 Left 0 !.MEASURE TRAN Output FIND V(OUT) AT=10m\n.MEASURE TRAN Ripple_Out PP V(OUT)\n.MEASURE TRAN Ripple_In PP V(SUPPLY)\n.MEASURE TRAN Gain1 PARAM (Ripple_Out / Ripple_In)\n.MEASURE TRAN Q2BE PARAM V(Q2B) - V(OUT)\n.MEASURE TRAN Vmon PARAM V(Q1E) - V(OUT) TEXT -1528 1096 Left 0 !.tran 0 0.2 0 TEXT -1528 992 Left 0 !.IC V(OUT)=0 V(M1G)=0 TEXT -1528 1016 Left 0 !.OPTIONS GMIN=1e-15 TEXT -1592 832 Left 0 ;.STEP TEMP LIST -55 25 TEXT -1528 968 Left 0 !.TEMP 25 TEXT -1528 1040 Left 0 !.LIB OPAMP.SUB TEXT -1528 1072 Left 0 !.INCLUDE LM139.5_1 TEXT -1440 152 Left 0 ;R4 (current monitoring resistor) = 0.5 Ohms.\nWant U1 to trigger at 150mA.\nV(Comp) is set to 75mV below V(SUPPLY) by V3, R1 & R2. TEXT -1056 880 Left 0 ;U1 goes low when\ncurrent through R4\nexceeds 150mA. TEXT -168 976 Left 0 ;U2 goes high when\nRload & Rfold allow\nV(OUT) > 1.50V TEXT -472 352 Left 0 ;If neither U1 nor U2 is low,\nthen M1 can be on. TEXT 8 104 Left 0 ;Provides 10mA Foldback Current when M1 is biased off.