Custom LED and TIP31CG for LTSpice.

Thread Starter

EEENg

Joined Apr 4, 2024
15
Hey guys, im pretty new to LTSPice and would like to include a custom LED and custom BJT.

The LED I'm completely lost, for reference I would like the "High intensity white" LED XQEAWT-H0-0000-00000HDE7 from https://downloads.cree-led.com/files/ds/x/XLamp-XQE.pdf into my circuit. I've found a useful txt file which I've tried to edit the parameters of the LEDs.

With the help of our trusty ChatGPT, it came up with
.MODEL DLED3 D (IS=93.1P RS=42M N=3.25 BV=1.2 IBV=10U CJO=2.97P VJ=.75 M=.333 TT=4.32U)

But I need it to reflect this.
1712250032782.png

As for the BJT, I would like a TIP31CG. I've found a useful model for the TIP31C, but I believe they're arent the same.

The model that is already there is

*.model TIP31C ako:NSC_4F NPN() ; case TO-220
.MODEL TIP31C NPN(Is=2.447p Xti=3 Eg=1.11 Vaf=100 Bf=208.2 Ise=70.69p
+ Ne=1.565 Ikf=.9743 Nk=.6134 Xtb=1.5 Br=12.59 Isc=11.68n
+ Nc=1.835 Ikr=3.86 Rc=.4685 Cjc=142p Mjc=.4353 Vjc=.75 Fc=.5
+ Cje=188.5p Mje=.4878 Vje=.75 Tr=194.2n Tf=19.85n Itf=164.1
+ Xtf=5.945 Vtf=10 Rb=.1)
*$

and I need it to be in accordance to this datasheet https://au.mouser.com/datasheet/2/308/1/TIP31A_D-2320157.pdf.

Currently the simulation is giving something stupidly small and unrealistic, any help would be greatly appreciated :).

Cheers.
 

ericgibbs

Joined Jan 29, 2010
19,003
Currently the simulation is giving something stupidly small and unrealistic, any help would be greatly appreciated
Hi EEE,
Welcome to AAC.
Please post your LTS asc file so that we can see the problem.
E
 

eetech00

Joined Jun 8, 2013
4,006
Hey guys, im pretty new to LTSPice and would like to include a custom LED and custom BJT.

The LED I'm completely lost, for reference I would like the "High intensity white" LED XQEAWT-H0-0000-00000HDE7 from https://downloads.cree-led.com/files/ds/x/XLamp-XQE.pdf into my circuit. I've found a useful txt file which I've tried to edit the parameters of the LEDs.

With the help of our trusty ChatGPT, it came up with
.MODEL DLED3 D (IS=93.1P RS=42M N=3.25 BV=1.2 IBV=10U CJO=2.97P VJ=.75 M=.333 TT=4.32U)
ChatGPT is not very good at spice modeling.
:(

Use these params for the XQ-E LED:

.MODEL XQEPCA D
+ IS=1.06795E-13
+ N=4.02995
+ RS=0.27786
+ XTI=52.51487
+ EG=2.5000
 

Thread Starter

EEENg

Joined Apr 4, 2024
15
'The G if for lead free. SPICE does not care.
The TIP31, 31a, 31b, 31c is for the max voltage. If you are using the part under 40V it will not matter.

Perfect thank you, my application is well under 40v. So using any of the TIP31 will be fine?
 

Thread Starter

EEENg

Joined Apr 4, 2024
15
ChatGPT is not very good at spice modeling.
:(

Use these params for the XQ-E LED:

.MODEL XQEPCA D
+ IS=1.06795E-13
+ N=4.02995
+ RS=0.27786
+ XTI=52.51487
+ EG=2.5000

Thank you so much,this should be what I need. But somehow I'm still not getting the values I'm trying to achieve
 

Thread Starter

EEENg

Joined Apr 4, 2024
15
Can't help you if we don't know what values you expect under what conditions.
Well with the dual BJT the current going through the LEDs should be 1A. The rest should just be according to the data sheet. But the1A would be my main goal.
 
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