Version 4 SHEET 1 880 1052 WIRE -576 -384 -736 -384 WIRE -480 -384 -576 -384 WIRE -160 -384 -400 -384 WIRE 64 -384 -160 -384 WIRE 80 -384 64 -384 WIRE -736 -368 -736 -384 WIRE -784 -352 -1056 -352 WIRE -1056 -320 -1056 -352 WIRE -1200 -304 -1216 -304 WIRE -1104 -304 -1200 -304 WIRE -784 -304 -800 -304 WIRE -800 -256 -800 -304 WIRE -736 -224 -736 -288 WIRE -1104 -208 -1104 -256 WIRE -1056 -208 -1056 -240 WIRE -784 -208 -928 -208 WIRE -784 -160 -800 -160 WIRE -800 -112 -800 -160 WIRE -736 -112 -736 -144 WIRE 64 48 64 -384 WIRE -160 64 -160 -384 WIRE -704 112 -736 112 WIRE -576 112 -624 112 WIRE -464 112 -512 112 WIRE -928 144 -928 -208 WIRE -736 160 -736 112 WIRE -736 160 -880 160 WIRE -736 176 -736 160 WIRE -464 192 -464 112 WIRE -464 192 -688 192 WIRE -384 192 -464 192 WIRE -160 192 -160 144 WIRE -160 192 -384 192 WIRE -640 240 -688 240 WIRE -608 240 -640 240 WIRE -928 256 -928 224 WIRE -880 256 -880 208 WIRE -160 256 -160 192 WIRE -736 304 -736 256 WIRE -640 304 -640 240 WIRE -1200 352 -1200 -304 WIRE -1200 464 -1200 432 WIRE -640 464 -640 384 WIRE -640 464 -1200 464 WIRE -160 464 -160 336 WIRE -160 464 -640 464 WIRE 64 464 64 128 WIRE 64 464 -160 464 WIRE 64 496 64 464 FLAG 64 496 0 FLAG 80 -384 OUT IOPIN 80 -384 Out FLAG -800 -112 0 FLAG -736 -112 0 FLAG -608 240 ref IOPIN -608 240 In FLAG -1216 -304 Vin IOPIN -1216 -304 In FLAG -1104 -208 0 FLAG -1056 -208 0 FLAG -880 256 0 FLAG -928 256 0 FLAG -800 -256 0 FLAG -576 -384 Vth FLAG -384 192 A FLAG -736 304 0 SYMBOL voltage -640 288 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 0 40 34 Left 0 WINDOW 3 42 62 Left 0 SYMATTR InstName V1 SYMATTR Value 2.5V SYMBOL res -176 48 R0 SYMATTR InstName Rupper SYMATTR Value 10k SYMBOL res -176 240 R0 SYMATTR InstName Rlower SYMATTR Value 10k SYMBOL e -736 -240 R0 SYMATTR InstName Hs2 SYMATTR Value 1 SYMBOL res -384 -400 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName RsOL SYMATTR Value 1 SYMBOL voltage -1200 336 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName Vin SYMATTR Value 15V SYMBOL e -1056 -336 R0 SYMATTR InstName X2 SYMATTR Value 0.05 SYMBOL res -608 96 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName Rf SYMATTR Value 100 SYMBOL cap -512 96 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName Cf SYMATTR Value 47nF SYMBOL e -928 128 M0 SYMATTR InstName E2 SYMATTR Value 10 SYMBOL e -736 -384 R0 SYMATTR InstName Hs1 SYMATTR Value 1 SYMBOL current 64 48 R0 WINDOW 123 24 116 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value2 AC 1 SYMATTR InstName I1 SYMATTR Value PULSE(0 1 10u 1u 1u 400u 802u) SYMBOL e2 -736 160 M0 SYMATTR InstName E1 SYMATTR Value 100 TEXT -1360 984 Left 0 !.tran 0 3m 10u TEXT -776 -416 Left 0 ;SUM2 TEXT -288 224 Left 0 ;Alpha = 0.5 TEXT -808 288 Left 0 ;Beta TEXT -1136 584 Left 0 ;RsCL = RsOL/(1+aHG) = RsOL/(1+T) = 1/(1+0.5*1*1000) = 1.996m TEXT -1144 -376 Left 0 ;AsOL = K = 0.05 TEXT -776 -72 Left 0 ;H = 1 TEXT -872 376 Left 0 ;G = E1*E2 = 1000 TEXT -632 -328 Left 0 ;Vth = Vout for no output load TEXT -1136 616 Left 0 ;Alpha = V(A)/V(out) = V(OUT)*Rlower/(Rlower+Rupper) TEXT -1136 552 Left 0 ;The closed loop output impedance RsCL is the output impedance as seen from Vth: dV(OUT)/dI(OUT) TEXT -632 -296 Left 0 ;RsOL is the open loop output impedance TEXT -1136 648 Left 0 ;AsOL = k = open-loop DC audio susceptibility = input ripple rejection = 50m: dV(OUT)/dV(in) TEXT -1136 680 Left 0 ;Transfer Function AsCL = AsOL/(1+aHG) = AsOL/(1+T) = 50m/(1+0.5*1*1000) = 99.8u TEXT -1360 1016 Left 0 !;TF V(OUT) Vin TEXT -336 888 Left 0 ;--- Transfer Function ---\n \nTransfer_function: 9.97964e-005 transfer\noutput_impedance_at_V(out): 0.00199593 impedance\nignore the input impedance vin TEXT -1200 480 Left 0 ;PULSE(15 500 10u 1u) TEXT -1136 704 Left 0 ;OL stands for open-loop, CL stands for close-loop, T stands for total loop gain TEXT -1360 952 Left 0 ;.IC V(OUT) = 0V TEXT -1360 920 Left 0 !;ac oct 100 10m 100k TEXT -1136 736 Left 0 ;For AC plot, Zout = Vout because Iout AC = 1 TEXT -1136 760 Left 0 ;The equivalent inductance Leq = Zout/(2*pi*f) = 100.6uH at f = 100Hz TEXT -1136 784 Left 0 ;With an 100uF output capacitor we get an LC resonant filter at f = 1/(2*pi*sqrt(Leq*C)) RECTANGLE Normal 328 1048 -1376 -512 RECTANGLE Normal -656 -48 -848 -432 RECTANGLE Normal -48 400 -320 32 RECTANGLE Normal -416 400 -1024 32