Version 4
SHEET 1 4144 2708
WIRE 2128 -480 1728 -480
WIRE 1728 -448 1728 -480
WIRE 2128 -336 2128 -480
WIRE 2128 -336 2080 -336
WIRE 2176 -336 2128 -336
WIRE 1728 -272 1728 -368
WIRE 2080 -240 2080 -272
WIRE 2080 -240 2000 -240
WIRE 2176 -240 2176 -272
WIRE 2368 -240 2176 -240
WIRE 2448 -240 2368 -240
WIRE 2608 -240 2448 -240
WIRE 2000 -224 2000 -240
WIRE 2080 -208 2080 -240
WIRE 2176 -208 2176 -240
WIRE 2368 -160 2368 -240
WIRE 2448 -160 2448 -240
WIRE 2608 -160 2608 -240
WIRE 2128 -144 2080 -144
WIRE 2176 -144 2128 -144
WIRE 1728 -96 1728 -192
WIRE 2368 -32 2368 -96
WIRE 2448 -32 2448 -96
WIRE 2608 -32 2608 -80
WIRE 1728 48 1728 -16
WIRE 2128 48 2128 -144
WIRE 2128 48 1728 48
FLAG 2000 -224 0
FLAG 2368 -32 0
FLAG 2448 -32 0
FLAG 2608 -32 0
SYMBOL voltage 1728 -288 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 326 50)
SYMBOL diode 2160 -336 R0
SYMATTR InstName D1
SYMATTR Value MUR460
SYMBOL diode 2064 -208 R0
WINDOW 0 -27 0 Left 2
WINDOW 3 125 66 Left 2
SYMATTR InstName D2
SYMATTR Value MUR460
SYMBOL diode 2096 -272 R180
WINDOW 0 24 72 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D3
SYMATTR Value MUR460
SYMBOL diode 2192 -144 R180
WINDOW 0 -33 67 Left 2
WINDOW 3 125 1 Left 2
SYMATTR InstName D4
SYMATTR Value MUR460
SYMBOL ntc_resistor 1712 -464 R0
WINDOW 123 52 120 Left 2
SYMATTR Value2 RTH=42  TAU=100
SYMATTR InstName R1
SYMATTR SpiceModel NTC_BTH
SYMATTR Value R0=5 B=3060
SYMBOL ntc_resistor 1712 -112 R0
WINDOW 123 52 120 Left 2
SYMATTR Value2 RTH=42  TAU=100
SYMATTR InstName R2
SYMATTR SpiceModel NTC_BTH
SYMATTR Value R0=5 B=3060
SYMBOL cap 2352 -160 R0
SYMATTR InstName C1
SYMATTR Value 470µ
SYMATTR SpiceLine Rser=190m
SYMBOL cap 2432 -160 R0
SYMATTR InstName C2
SYMATTR Value 470µ
SYMATTR SpiceLine Rser=190m
SYMBOL res 2592 -176 R0
SYMATTR InstName R3
SYMATTR Value 250
TEXT 1712 -984 Left 2 ;.OP
TEXT 1712 -1056 Left 2 ;.STEP TEMP  0 50 10
TEXT 1960 -1088 Left 2 !.OPTIONS TNOM={T0}
TEXT 1960 -1056 Left 2 !.PARAM TK=273.15\n.PARAM T0=25
TEXT 744 -1096 Left 2 ;Dynamic Model for the NTC Thermistor in LTSPICE      \n-------------------------------------------------------------------------------\n 7/30/2004   Helmut Sennewald\nHint: The unit Ohm can be achieved on the y-axis if V(node)/1A is plotted.\n \ndT=TEMP-T0\nTEMP = T0 + dT\nT = TEMP+TK\nT0 is 27 degree for SPICE. It can be overwritten with e.g. ".OPTIONS TNOM=25".\nTK is 273.15 degree.\nR0 is resistance at a defined temperature, mostly 25 degree for NTC-thermistors.\n \n \nExponential temperature dependence\n-----------------------------------------------------------\nThis is a very common formula used for NTC thermistors.\nB is a material constant, e.g. B=3988\nB = T1*T2/(T2-T1)*ln(R1/R2)      R1, R2 is resistance at T1, T2\nR0 is resistance at T1 .\n \nFormula:  R = R0*exp(B*( 1/(TEMP+TK) - 1/(T0+TK) ))\nT = B/( ln(R/R0)+B/(T0+TK) )\nExample:  NTC with B=3988\n.PARAM R0=10000\n.PARAM B=3988\n.PARAM TK=273.15\n.PARAM T0=25\n*R1 n1 n2 {R0*exp(B*( 1/(TEMP+TK) - 1/(TNOM+TK) ))}\nReplace resistor R1 by a voltage controlled current source B1(Bi-source)\nB1 n1 n2  I=V(n1,n2)/{R0*exp(3988*(1/(TEMP+TK)-1/(T0+TK)))}\n \nThermal model for self heating\n------------------------------------------------\nThe current through the thermistor rises the thermistor's temperature.\ndTth =  P * Rth\nRth is the thermal resistance in degree/Watt \nRth = 1/delta_th in the EPCOS datasheet\nCth = TAU/Rth is the time constant\nPtherm = V*V/Rtherm \nV is the voltage acroos the thermistor.
TEXT 736 56 Left 2 !.SUBCKT NTC_BTH 1 2  R0={R0} B={B} RTH={RTH} TAU={TAU} \n* R0 resistance at 25degree\n* B material constant\n* Rth thermal resistance in degree/Watt\n* TAU time constant \n*.PARAM R0=10000\n*.PARAM B=3988\n.PARAM TK=273.15\n.PARAM T0=25\n* Resistor model\nRP 1 2 1G\nB1 1 2  I=V(1,2)/{R0*exp(B*(1/(V(3)+TEMP+TK)-1/(T0+TK)))}\n* Thermal model\n*V(3) is dT = Tntc-TEMP\nRTH 3 0  {RTH}\nCTH 3 0 {TAU/RTH}\nBTH 0 3  I=V(1,2)*V(1,2)/{R0*exp(B*(1/(V(3)+TEMP+TK)-1/(T0+TK)))}\n.ENDS
TEXT 1712 -1024 Left 2 !.TRAN 200
TEXT 1712 -1088 Left 2 !.options TEMP=25