Version 4 SHEET 1 1832 792 WIRE 704 -240 576 -240 WIRE 816 -240 768 -240 WIRE 576 -192 576 -240 WIRE 640 -192 576 -192 WIRE 816 -192 816 -240 WIRE 816 -192 720 -192 WIRE -832 -144 -832 -176 WIRE -688 -144 -688 -176 WIRE 736 -96 736 -112 WIRE -336 -80 -496 -80 WIRE -64 -80 -240 -80 WIRE 96 -80 -64 -80 WIRE 528 -80 96 -80 WIRE 576 -80 576 -192 WIRE 576 -80 528 -80 WIRE 704 -80 576 -80 WIRE 96 -64 96 -80 WIRE 816 -64 816 -192 WIRE 816 -64 768 -64 WIRE 864 -64 816 -64 WIRE -832 -48 -832 -64 WIRE -752 -48 -832 -48 WIRE -688 -48 -688 -64 WIRE -608 -48 -688 -48 WIRE -496 -48 -496 -80 WIRE 704 -48 576 -48 WIRE -832 -32 -832 -48 WIRE -752 -32 -752 -48 WIRE -688 -32 -688 -48 WIRE -608 -32 -608 -48 WIRE 576 16 576 -48 WIRE 736 16 736 -32 WIRE 96 32 96 16 WIRE 176 32 96 32 WIRE 256 32 240 32 WIRE -496 48 -496 32 WIRE 96 48 96 32 WIRE -64 64 -64 -80 WIRE -832 80 -832 48 WIRE -688 80 -688 48 WIRE 96 144 96 128 WIRE 176 144 96 144 WIRE -240 176 -240 -80 WIRE 160 208 160 192 WIRE -336 224 -336 -80 WIRE -304 224 -336 224 WIRE -272 224 -304 224 WIRE -176 224 -192 224 WIRE 96 224 96 144 WIRE 128 224 96 224 WIRE -64 240 -64 128 WIRE -16 240 -64 240 WIRE 240 240 240 144 WIRE 240 240 192 240 WIRE 304 240 240 240 WIRE 416 240 384 240 WIRE 448 240 416 240 WIRE 576 240 576 96 WIRE 576 240 528 240 WIRE -16 256 -16 240 WIRE 128 256 96 256 WIRE 576 256 576 240 WIRE 160 288 160 272 WIRE 416 288 416 240 WIRE -640 304 -720 304 WIRE -576 304 -640 304 WIRE -496 304 -576 304 WIRE -448 304 -496 304 WIRE -288 304 -368 304 WIRE -176 304 -176 224 WIRE -176 304 -288 304 WIRE -64 320 -64 240 WIRE -720 336 -720 304 WIRE -640 336 -640 304 WIRE -576 336 -576 304 WIRE -496 336 -496 304 WIRE 96 352 96 256 WIRE 416 368 416 352 WIRE 576 368 576 336 WIRE 720 432 576 432 WIRE 816 432 784 432 WIRE 96 448 96 432 WIRE 160 448 96 448 WIRE 240 448 224 448 WIRE -720 464 -720 400 WIRE -640 464 -640 416 WIRE -640 464 -720 464 WIRE -576 464 -576 400 WIRE -576 464 -640 464 WIRE -496 464 -496 416 WIRE -496 464 -576 464 WIRE 96 464 96 448 WIRE 576 496 576 432 WIRE 608 496 576 496 WIRE 816 496 816 432 WIRE 816 496 688 496 WIRE -640 544 -640 464 WIRE 720 576 720 560 WIRE -240 592 -240 256 WIRE -64 592 -64 384 WIRE -64 592 -240 592 WIRE 96 592 96 544 WIRE 96 592 -64 592 WIRE 512 592 96 592 WIRE 576 592 576 496 WIRE 576 592 512 592 WIRE 688 592 576 592 WIRE 816 608 816 496 WIRE 816 608 752 608 WIRE 848 608 816 608 WIRE 688 624 560 624 WIRE -640 656 -640 624 WIRE 560 656 560 624 WIRE 720 688 720 640 WIRE 560 768 560 736 FLAG 864 -64 Vout1 IOPIN 864 -64 Out FLAG 560 768 0 FLAG 848 608 Vout2 IOPIN 848 608 Out FLAG -752 -32 0 FLAG -832 -176 +12V FLAG -832 80 -12V FLAG 736 -112 +12V FLAG 720 560 +12V FLAG 720 688 -12V FLAG 736 16 -12V FLAG -608 -32 0 FLAG -688 -176 +3V FLAG -688 80 -3V FLAG 160 288 -3V FLAG 160 192 +3V FLAG 416 368 0 FLAG 528 -80 Vd1 FLAG 512 592 Vd2 FLAG -16 256 0 FLAG -496 48 0 FLAG -304 224 pos FLAG -288 304 vpd FLAG 240 448 0 FLAG 256 32 0 FLAG -640 656 0 FLAG 576 368 0 SYMBOL diode -736 336 R0 SYMATTR InstName D1 SYMBOL voltage 576 0 R0 WINDOW 3 26 91 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value -2m SYMATTR InstName Vos1 SYMBOL res 624 -176 R270 WINDOW 0 35 55 VTop 0 WINDOW 3 -32 59 VTop 0 SYMATTR InstName Rv1 SYMATTR Value 2Meg SYMBOL res 592 512 R270 WINDOW 0 35 53 VTop 0 WINDOW 3 -30 44 VTop 0 SYMATTR InstName Rv2 SYMATTR Value 2Meg SYMBOL voltage 560 640 R0 WINDOW 3 14 98 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value 2m SYMATTR InstName Vos2 SYMBOL current -640 416 R180 WINDOW 0 24 88 Left 0 WINDOW 3 24 0 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I1 SYMATTR Value 2µ SYMBOL Opamps\\LT1464 736 -128 R0 SYMATTR InstName U1 SYMBOL Opamps\\LT1464 720 544 R0 SYMATTR InstName U2 SYMBOL voltage -832 -160 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 12 SYMBOL voltage -832 -48 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 12 SYMBOL cap 240 128 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 1µ SYMBOL voltage -688 -160 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 12 SYMBOL voltage -688 -48 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 12 SYMBOL res 400 224 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName Roc1 SYMATTR Value 100k SYMBOL cap 400 352 M180 WINDOW 0 24 64 Left 0 WINDOW 3 24 8 Left 0 SYMATTR InstName Coc1 SYMATTR Value 1µ SYMBOL cap 704 -224 R270 WINDOW 0 24 -15 VTop 0 WINDOW 3 51 68 VBottom 0 SYMATTR InstName C3 SYMATTR Value 10p SYMBOL cap 720 448 R270 WINDOW 0 40 31 VTop 0 WINDOW 3 3 35 VBottom 0 SYMATTR InstName C4 SYMATTR Value 10p SYMBOL cap -560 400 R180 WINDOW 0 -2 55 Right 0 WINDOW 3 2 8 Right 0 SYMATTR InstName C5 SYMATTR Value 50p SYMBOL res -480 432 R180 WINDOW 0 -1 32 Right 0 WINDOW 3 -11 -3 Right 0 SYMATTR InstName Rparallel SYMATTR Value 1Meg SYMBOL Opamps\\LTC2055 160 240 R0 SYMATTR InstName U4 SYMBOL cap -48 128 R180 WINDOW 0 -2 55 Right 0 WINDOW 3 2 8 Right 0 SYMATTR InstName C6 SYMATTR Value 25p SYMBOL cap -48 384 R180 WINDOW 0 -2 55 Right 0 WINDOW 3 2 8 Right 0 SYMATTR InstName C7 SYMATTR Value 25p SYMBOL res -464 320 R270 WINDOW 0 69 27 VTop 0 WINDOW 3 64 31 VBottom 0 SYMATTR InstName Rserial SYMATTR Value 100 SYMBOL potentiometer_vc -256 160 R0 SYMATTR InstName PSD SYMATTR Description Resistor Potentiometer with voltage control input SYMBOL voltage -496 -64 R0 WINDOW 3 -76 -44 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value PULSE(0.1 0.9 100u 1u 1u 5m 10m) SYMATTR InstName V7 SYMBOL res 80 32 R0 SYMATTR InstName R1b SYMATTR Value 100k SYMBOL res 80 448 R0 SYMATTR InstName R2b SYMATTR Value 100k SYMBOL res 80 336 R0 SYMATTR InstName R2 SYMATTR Value 100k SYMBOL cap 160 464 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C2b SYMATTR Value .01µ SYMBOL cap 176 48 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName C1b SYMATTR Value .01µ SYMBOL voltage -640 528 R0 SYMATTR InstName VBIAS SYMATTR Value 0 SYMBOL res 80 -80 R0 SYMATTR InstName R1 SYMATTR Value 100k SYMBOL res 560 240 R0 SYMATTR InstName Roc3 SYMATTR Value 1k SYMBOL res 432 256 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 0 56 VBottom 0 SYMATTR InstName Roc2 SYMATTR Value 100k TEXT -752 408 VLeft 0 ;Iphoto TEXT -328 344 Right 0 ;Iphoto + Ios TEXT -72 -96 Right 0 ;Iphoto1 TEXT -72 576 Right 0 ;Iphoto2 TEXT -464 776 Left 0 !.tran 20m TEXT -464 744 Left 0 !.op TEXT -464 680 Left 0 !.include potentiometer_vc.sub TEXT -464 712 Left 0 !.options plotwinsize=0; data compression off TEXT -440 -32 Left 0 ;control \nvoltage\n0..1V TEXT -600 592 Left 0 ;optional extenal Vbias TEXT -680 224 Left 0 ;PSD Model TEXT -576 -376 Left 0 ;PSD (Position Sensitive Device)\n(Voltage controlled potentiometer used for the PSD model)\nUse reasonable rise/fall times for the position change.\nU4 compensates for any offset voltage of U1 and U2.\nThe loop filter attenuates the noise of U4. TEXT 0 -144 Left 0 ;Maybe there is some noise striking back \nfrom U4. R1b,C1b, R2b,C2b can filter it. TEXT 408 168 Left 0 ;loop filter LINE Normal -384 192 -736 192 LINE Normal -384 128 -384 192 LINE Normal -112 128 -384 128 LINE Normal -112 384 -112 128 LINE Normal -304 384 -112 384 LINE Normal -304 496 -304 384 LINE Normal -800 496 -304 496 LINE Normal -800 192 -800 496 LINE Normal -736 192 -800 192 RECTANGLE Normal 656 400 288 144