Version 4
SHEET 1 1564 772
WIRE -176 -16 -208 -16
WIRE -128 -16 -176 -16
WIRE 64 -16 32 -16
WIRE 112 -16 64 -16
WIRE 304 -16 272 -16
WIRE 352 -16 304 -16
WIRE 544 -16 496 -16
WIRE 688 -16 640 -16
WIRE 832 -16 784 -16
WIRE 976 -16 928 -16
WIRE -208 16 -208 -16
WIRE -128 16 -128 -16
WIRE 32 16 32 -16
WIRE 112 16 112 -16
WIRE 272 16 272 -16
WIRE 352 16 352 -16
WIRE 496 16 496 -16
WIRE 640 16 640 -16
WIRE 784 16 784 -16
WIRE 928 16 928 -16
WIRE -208 112 -208 96
WIRE -128 112 -128 80
WIRE -128 112 -208 112
WIRE 32 112 32 96
WIRE 112 112 112 80
WIRE 112 112 32 112
WIRE 272 112 272 96
WIRE 352 112 352 80
WIRE 352 112 272 112
WIRE 496 112 496 96
WIRE 640 112 640 96
WIRE 784 112 784 96
WIRE 928 112 928 96
WIRE -208 128 -208 112
WIRE 32 128 32 112
WIRE 272 128 272 112
WIRE 896 224 784 224
WIRE 928 224 896 224
WIRE 784 256 784 224
WIRE 928 256 928 224
WIRE 784 368 784 336
WIRE 928 368 928 320
WIRE 928 368 784 368
WIRE 784 384 784 368
FLAG -208 128 0
FLAG -176 -16 VF1
FLAG 32 128 0
FLAG 64 -16 VF2
FLAG 496 112 0
FLAG 544 -16 N
IOPIN 544 -16 Out
FLAG 640 112 0
FLAG 688 -16 Is
IOPIN 688 -16 Out
FLAG 784 112 0
FLAG 832 -16 Rs
IOPIN 832 -16 Out
FLAG 272 128 0
FLAG 304 -16 VF3
FLAG 928 112 0
FLAG 976 -16 Eg
IOPIN 976 -16 Out
FLAG 784 384 0
FLAG 896 224 VF_green
SYMBOL diode -144 16 R0
SYMATTR InstName D1
SYMATTR Value DMOD
SYMBOL current -208 96 R180
WINDOW 0 24 88 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName I1
SYMATTR Value {I1}
SYMBOL diode 96 16 R0
SYMATTR InstName D2
SYMATTR Value DMOD
SYMBOL current 32 96 R180
WINDOW 0 24 88 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName I2
SYMATTR Value {I2}
SYMBOL voltage 496 0 R0
SYMATTR InstName V1
SYMATTR Value {N}
SYMBOL voltage 640 0 R0
SYMATTR InstName V2
SYMATTR Value {Is}
SYMBOL voltage 784 0 R0
SYMATTR InstName V3
SYMATTR Value {Rs}
SYMBOL diode 336 16 R0
SYMATTR InstName D3
SYMATTR Value DMOD
SYMBOL current 272 96 R180
WINDOW 0 24 88 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName I3
SYMATTR Value {I3}
SYMBOL voltage 928 0 R0
SYMATTR InstName V4
SYMATTR Value {Eg}
SYMBOL current 784 336 M180
WINDOW 0 24 88 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName I4
SYMATTR Value 50u
SYMBOL diode 912 256 R0
SYMATTR InstName D_GREEN
SYMATTR Value LED_GREEN
TEXT -224 -424 Left 2 !.param Vf2=1.80
TEXT -224 -496 Left 2 !.param Vf1=1.71
TEXT -224 -528 Left 2 !.param I1=0.00005
TEXT -224 -456 Left 2 !.param I2=0.00055
TEXT 256 -592 Left 2 !.param T0=273.15+Tmeas\n.param Vt = k*T0/q\n.param N = (Vf2-Vf1)/(Vt*ln(I2/I1))\n.param Is= I1/exp(Vf1/(N*Vt))\n.param Rs=(Vf3-ln(I3/Is)*(N*Vt))/I3
TEXT 256 -440 Left 2 !.param XTI=3\n.param T1=T0+1\n.param deltaT=T1-T0\n.param Vt_t0=Vt\n.param Vt_t1=Vt_t0*(1+(T1-T0)/T0)\n.param Vf_t0=Vf1\n.param Vf_t1=Vf_t0+Tempco*deltaT\n.param Is_t0=Is\n.param Is_t1=I1/exp(Vf_t1/(N*Vt_t1))\n.param Eg=N*Vt_t1*T0/(T1-T0)*ln(Is_t1/(Is_t0*(T1/T0)**(XTI/N)))
TEXT 744 -568 Left 2 !.param k=boltz\n.param q=echarge
TEXT 0 -112 Left 2 !.model  DMOD D(Is={Is} N={N} Rs={Rs} Eg={Eg} Tnom={Tmeas})
TEXT -248 -80 Left 2 !.OP
TEXT -224 -384 Left 2 !.param I3=0.01
TEXT -224 -352 Left 2 !.param VF3=1.96
TEXT -224 -296 Left 2 !* Tempco @I1  (50uA)\n.param Tempco=-0.002
TEXT 128 -480 Left 2 ;N and Is
TEXT 128 -360 Left 2 ;Rs
TEXT 128 -304 Left 2 ;Eg
TEXT -256 360 Left 2 !.model  LED_GREEN D(Is=8.2e-25 N=1.46 Rs=5.1 Eg=2.23 Tnom={Tmeas})
TEXT -248 -112 Left 2 !.TEMP {Tmeas}
TEXT -224 -568 Left 2 !.param Tmeas=25
TEXT -256 -1032 Left 2 ;Calculation Of Diode(LED) SPICE Parameters For DC.      V1.1\n \nN and Is: Measure Vf at low currents e.g. 50uA and 500uA\nRs: Measure Vf at high current, e.g. 10mA\nEg: Enter temperature coefficient Tempco, e.g. -0.002 V/degree for Si, green-LED\n      Typical values of Eg: Si 1.11, Sbd 0.69, Ge 0.67, In 3.0 from SCAD3-help\n \nChoose Tmeas=27deg to avoid the parameter Tnom={} in the diode model!\n \nThe blue data values in .param are measured with a green LED and \nthe active values are measured with a red LED.\n \nEnable the .step command very below to make a nice Vf(Idiode) plot.
TEXT 752 -608 Left 2 ;General constants
TEXT -256 312 Left 2 ;.step oct I4 10u 50m 50
TEXT 32 312 Left 2 ;Enable this line for Vf(Idiode) plot
TEXT 760 -352 Left 2 !.meas Vt_ param Vt\n.meas Is_ param Is\n.meas N_ param N\n.meas Rs_ param Rs
TEXT -256 264 Left 2 ;.step TEMP 25 26
TEXT -208 -624 Left 2 ;Measured Values
TEXT 760 -400 Left 2 ;Results to Logfile
TEXT 312 -624 Left 2 ;Calculation
LINE Normal 80 -592 -256 -592 1
LINE Normal 80 -224 80 -592 1
LINE Normal -256 -224 80 -224 1
LINE Normal -256 -592 -256 -224 1
LINE Normal -256 -592 -256 -592 2
LINE Normal 112 -336 112 -384
LINE Normal 96 -336 112 -336
LINE Normal 96 -384 112 -384
LINE Normal 112 -400 112 -544
LINE Normal 96 -400 112 -400
LINE Normal 96 -544 112 -544
LINE Normal 112 -272 112 -320
LINE Normal 96 -272 112 -272
LINE Normal 96 -320 112 -320