* SPICE netlist
Q2 N006 N006 N009 0 2N3904
D1 0 N009 BZX84C6V2L
R1 VCC N006 4.7k
R2 VCC N001 0.47
R3 N008 N010 {R_SET}
V1 VCC 0 {VCC}
Q3 DB N006 N007 0 2N3904
R4 N007 0 4.7k
Q4 PC PB PE 0 TIP42C
Q5 N004 DB PB 0 2N3906
Q7 N003 N003 N002 0 2N3906
Q6 N003 N003 DB 0 2N3904
R7 VCC VT 145
R13 VT N002 145
RT VCC VT {300*exp(beta*(1/(TEMP+273.15)-1/(25+273.15)))}
Q1 0 0 N004 0 TIP42C
S1 N005 PC V_SW 0 LDSW
V2 V_SW 0 PULSE(0 1 50n 1n 1n 300n 20000n 10)
D2 PC PB BAT54SHY
L1 N005 N008 {L_SET}
L2 N001 PE 4.7n
L3 N010 0 {L_SET/2048}
.tran 0.5u
;.step temp 0 50 2
.param R_SET 3.25k
;.step param VCC 18 25 1
.param VCC=20
;.step param R_SET 100 350 5
.param beta=3468
;.step param beta 3100 4000 100
.step param R_SET 15 30 2
.temp 25
.step param L_SET list 2u 3u 4u

* LTspice schematic (.asc)
Version 4
SHEET 1 1616 1424
WIRE -632 -712 -808 -712
WIRE -472 -712 -632 -712
WIRE -136 -712 -472 -712
WIRE 584 -712 -136 -712
WIRE 584 -664 584 -712
WIRE -136 -600 -136 -712
WIRE -136 -600 -328 -600
WIRE 584 -568 584 -584
WIRE -328 -536 -328 -600
WIRE -136 -536 -136 -600
WIRE 584 -456 584 -488
WIRE -328 -408 -328 -456
WIRE -184 -408 -328 -408
WIRE -136 -408 -136 -456
WIRE -136 -408 -184 -408
WIRE 584 -392 584 -456
WIRE -136 -344 -136 -408
WIRE 520 -344 296 -344
WIRE 584 -248 584 -296
WIRE -136 -216 -136 -264
WIRE 296 -184 296 -344
WIRE 296 -184 104 -184
WIRE 472 -184 296 -184
WIRE 584 -184 584 -248
WIRE 584 -184 536 -184
WIRE -200 -168 -296 -168
WIRE -296 -88 -296 -168
WIRE -136 -88 -136 -120
WIRE -136 -88 -296 -88
WIRE -136 -56 -136 -88
WIRE -296 -8 -296 -88
WIRE -200 -8 -296 -8
WIRE 104 88 104 -184
WIRE 696 88 632 88
WIRE 808 88 696 88
WIRE 584 120 584 -184
WIRE 808 120 808 88
WIRE -472 136 -472 -712
WIRE -136 136 -136 40
WIRE -104 136 -136 136
WIRE 40 136 -104 136
WIRE 632 136 632 88
WIRE -808 168 -808 -712
WIRE 104 216 104 184
WIRE 632 232 632 184
WIRE 680 232 632 232
WIRE 808 232 808 200
WIRE 808 232 680 232
WIRE 216 264 168 264
WIRE 584 264 584 200
WIRE -472 280 -472 216
WIRE -264 280 -472 280
WIRE 680 280 680 232
WIRE -472 312 -472 280
WIRE -136 312 -136 136
WIRE -264 360 -264 280
WIRE -264 360 -408 360
WIRE -200 360 -264 360
WIRE 104 392 104 312
WIRE 216 392 216 264
WIRE 216 392 104 392
WIRE -136 424 -136 408
WIRE 584 424 584 344
WIRE -472 488 -472 408
WIRE 584 584 584 504
WIRE -808 680 -808 248
WIRE -536 680 -808 680
WIRE -472 680 -472 552
WIRE -472 680 -536 680
WIRE -136 680 -136 504
WIRE -136 680 -472 680
WIRE 104 680 104 392
WIRE 104 680 -136 680
WIRE 584 680 584 664
WIRE 584 680 104 680
WIRE -536 712 -536 680
FLAG -536 712 0
FLAG 584 -456 PE
FLAG 584 -248 PC
FLAG -184 -408 VT
FLAG -632 -712 VCC
FLAG 104 -184 PB
FLAG -104 136 DB
FLAG 680 280 0
FLAG 696 88 V_SW
SYMBOL npn -408 312 M0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL zener -456 552 R180
SYMATTR InstName D1
SYMATTR Value BZX84C6V2L
SYMBOL res -488 120 R0
SYMATTR InstName R1
SYMATTR Value 4.7k
SYMBOL res 568 -680 R0
SYMATTR InstName R2
SYMATTR Value 0.47
SYMBOL res 568 408 R0
SYMATTR InstName R3
SYMATTR Value {R_SET}
SYMBOL voltage -808 152 R0
SYMATTR InstName V1
SYMATTR Value {VCC}
SYMBOL npn -200 312 R0
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL res -152 408 R0
SYMATTR InstName R4
SYMATTR Value 4.7k
SYMBOL pnp 520 -296 M180
SYMATTR InstName Q4
SYMATTR Value TIP42C
SYMBOL pnp 40 184 M180
SYMATTR InstName Q5
SYMATTR Value 2N3906
SYMBOL pnp -200 -120 M180
SYMATTR InstName Q7
SYMATTR Value 2N3906
SYMBOL npn -200 -56 R0
SYMATTR InstName Q6
SYMATTR Value 2N3904
SYMBOL res -152 -552 R0
SYMATTR InstName R7
SYMATTR Value 145
SYMBOL res -152 -360 R0
SYMATTR InstName R13
SYMATTR Value 145
SYMBOL res -344 -552 R0
SYMATTR Value {300*exp(beta*(1/(TEMP+273.15)-1/(25+273.15)))}
SYMATTR InstName RT
SYMBOL pnp 168 312 R180
SYMATTR InstName Q1
SYMATTR Value TIP42C
SYMBOL sw 584 216 R180
SYMATTR InstName S1
SYMATTR Value LDSW
SYMBOL voltage 808 104 R0
SYMATTR Value PULSE(0 1 50n 1n 1n 300n 20000n 10)
SYMATTR InstName V2
SYMBOL schottky 536 -200 R90
SYMATTR InstName D2
SYMATTR Value BAT54SHY
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL ind 568 248 R0
SYMATTR InstName L1
SYMATTR Value {L_SET}
SYMBOL ind 568 -584 R0
SYMATTR InstName L2
SYMATTR Value 4.7n
SYMBOL ind 568 568 R0
SYMATTR InstName L3
SYMATTR Value {L_SET/2048}