Version 4 SHEET 1 1684 1876 WIRE -384 80 -400 80 WIRE -256 80 -384 80 WIRE 0 80 -32 80 WIRE 32 80 0 80 WIRE 64 80 32 80 WIRE 160 80 128 80 WIRE 272 80 240 80 WIRE 336 80 272 80 WIRE 544 80 336 80 WIRE 592 80 544 80 WIRE 336 96 336 80 WIRE -384 128 -384 80 WIRE 544 128 544 80 WIRE 32 144 32 80 WIRE -256 176 -288 176 WIRE 336 176 336 160 WIRE -160 240 -160 208 WIRE -160 240 -176 240 WIRE -384 272 -384 208 WIRE -80 272 -80 208 WIRE -80 272 -384 272 WIRE 32 272 32 208 WIRE 32 272 -80 272 WIRE 336 272 336 240 WIRE 336 272 32 272 WIRE 544 272 544 208 WIRE 544 272 336 272 WIRE -384 288 -384 272 WIRE -288 336 -288 176 WIRE -224 336 -288 336 WIRE -96 336 -160 336 WIRE -288 416 -288 336 WIRE -272 416 -288 416 WIRE -176 416 -208 416 WIRE -96 416 -96 336 WIRE -96 416 -112 416 WIRE 272 464 272 80 WIRE -96 544 -96 416 WIRE 272 544 272 528 WIRE 272 544 -96 544 WIRE -96 560 -96 544 WIRE -96 560 -160 560 WIRE 272 560 272 544 WIRE -288 576 -288 416 WIRE -288 576 -320 576 WIRE -224 576 -288 576 WIRE -48 592 -160 592 WIRE -48 624 -48 592 WIRE 272 656 272 624 WIRE -48 736 -48 704 FLAG 592 80 OUT IOPIN 592 80 Out FLAG -400 80 IN IOPIN -400 80 In FLAG -320 576 Verr IOPIN -320 576 Out FLAG 0 80 c FLAG -176 240 Duty IOPIN -176 240 Out FLAG 272 656 0 FLAG -384 288 0 FLAG -48 736 0 SYMBOL ind2 144 96 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 4 56 VBottom 0 SYMATTR InstName L1 SYMATTR Value 35µH SYMBOL res2 320 96 R0 SYMATTR InstName Resr SYMATTR Value 70m SYMBOL cap 320 176 R0 SYMATTR InstName Cout SYMATTR Value 100µF SYMBOL voltage -384 112 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 3 -86 214 Left 0 SYMATTR Value 8.24V SYMATTR InstName V4 SYMBOL res2 -208 400 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName R1 SYMATTR Value 20k SYMBOL cap -112 400 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 10nF SYMBOL cap -160 320 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C2 SYMATTR Value 470pF SYMBOL voltage -48 608 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 2.5V SYMBOL res2 64 96 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName R4 SYMATTR Value 20m SYMBOL res2 256 560 R0 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL res2 256 464 R0 SYMATTR InstName R7 SYMATTR Value 10k SYMBOL current 544 128 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I1 SYMATTR Value PULSE(0.13 0.3 1u 100u 100u 3.99m 8m) SYMBOL res2 16 144 R0 SYMATTR InstName Rdum SYMATTR Value 100k SYMBOL BUCK-CCM-DCM-CM-AC -112 128 R0 WINDOW 39 -149 -128 Left 0 SYMATTR SpiceLine L=35u Fsw=200k Ri=1 Se=100m SYMATTR InstName X2 SYMBOL Opamps\\opamp -192 512 M0 WINDOW 0 3 -20 Right 0 WINDOW 39 24 9 Right 0 WINDOW 40 79 116 Right 0 SYMATTR InstName X3 SYMATTR SpiceLine Aol=1K TEXT -440 752 Left 0 !.tran 20m TEXT -256 -24 Left 0 ;L=35u Fsw=200k Ri=1 Se=100m TEXT -464 -192 Left 0 ;Convergence problem isolated down to varicap model as a substitute for inductor current memory (page 158, starting from page 146)\nAfter fixing varicap, convergence errors isolated down to voltage oscillations crossing zero and used to divide some other expressions\nDivide by zero in expressions fixed with aditional limits on the affected expressions (see internal schematic of BUCK-CCM-DCM-CM)M\nFollowing Christhophe's advise, the whole capacitor was removed for average model used in transient simulations\nFor AC response, use BUCK-CCM-DCM-CM-AC mode; for transient response, use BUCK-CCM-DCM-CM (without resonant capacitor) TEXT 376 328 Left 0 ;Ri = (Verr max abs)/(Ic max abs) = Verr/Ic (max)\nVerr = maximum internal amplitude of ramp refference\nIc max abs = absolute maximum switch current\nRi = hypothetical resistor used as current transductor\nHere Ri = 1 in order to have the real current coefficient = 1\nRi voltage dropp is the equivalent voltage of c current (page 154) TEXT 224 -32 Left 0 ;Sometimes the model will show fast oscillations: why?\nTo avoid small fast oscillations if input voltage colud not be increased do\nnot use max Timestep and use spice integration Gear TEXT -368 240 Left 0 ;(8.24V) TEXT 376 568 Left 0 ;Recommended SPICE Settings to avoid fast oscillations:\nIntegratiion = Gear TEXT 96 704 Left 0 ;For this particular model with AC sweep option we get best transient results\nIf the transient model is employed, the missing internal capacitor must be provided\nexternally from "c" net to GND (1pF capacitor will suffice) TEXT -432 728 Left 0 ;.IC V(OUT)=5 TEXT -424 688 Left 0 !.lib opamp.sub RECTANGLE Normal -480 -224 1120 800