LTspice@groups.io

Re: High-power Infrared LED model desired

John Woodgate

In message <kkf6tn+ghqn@...>, dated Sun, 14 Apr 2013, Helmut
<helmutsennewald@...> writes:

Most models from other vendors don't have Ikf at all. So the models
from OSRAM are at least as good as the models from other vendors. I
recommend to use the OSRAM models.It isn't how good the models are that is bugging me; it's the unreality
of giving the parameters to so many significant figures. I suspect that
if tolerances were added we would see:

  IKF = 392.8188163 +/-1%,

so that only a value of 393 is justified, given a range of 388.9 to
396.7.  But even if the tolerance is 0.1%, the same argument applies; to
state 10 figures is meaningless.

But it's hardly a matter of outstanding global importance.
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: High-power Infrared LED model desired

#62680

--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:

The model for the OSRAM SFH4248 is in the file
OSRAM-IR-POWERTOPLED.lib

Thanks!

I saw their SPICE models but not that one. And the "Simulation Models" link from the part's page led nowhere.

Re: High-power Infrared LED model desired

#62679

Hello John,

Most models from other vendors don't have Ikf at all.
So the models from OSRAM are at least as good as the models
from other vendors. I recommend to use the OSRAM models.

Best regards,
Helmut

Show quoted text

--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <kkf3is+3juc@...>, dated Sun, 14 Apr 2013, Helmut
<helmutsennewald@...> writes:

N=     1.570213683
+      RS=     0.762136823
+      IKF=    392.8188163Not Helmut's responsibility, but isn't it disquieting that these are
given to 10 significant figures? Doesn't inspire confidence. Can we sue
if IKF turns out to be 392.8188162?(;-)
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Things to do today: Cut a hole in reality and push a turnip through.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: THD of a sine with a small dent at crossover

#62678

Greetings,

If we make some assumptions then the math becomes easy enough that even I can do it.  First, imagine that you are taking a pure sinewave and subtracting a small signal from it to create the waveform you want.  The pure sinewave has no distortion, while the small signal looks roughly like a tiny triangle starting at 0V and reaching some maximum voltage before dropping back to 0V, symmetrically at each zero crossing.  That maximum voltage is sine(2 pi D / T), for small values of D/T this is about linear.

If we assume that your 'dent' is small enough that it does not appreciably affect the energy at the fundamental frequency (i.e. the distortion is 'small'), then the total distortion is roughly the ratio of the RMS value of small pulse divided by the RMS voltage of the fundamental.

It's simple to show that the RMS value of a triangular pulse is proportional to (D/T)^1.5 as Helmut stated in the other thread, so that should be what you observe in THD also.  The reason this disagrees with what you found has to do with the way THD is calculated by the .FOUR function.  Notice that the error log shows Fourier components up to 9th order, or 9kHz in your example.  Note also that the magnitude of the distortion components is the SAME for each one (since your signal is symmetric there will only be odd components, ignore the even ones as they are noise), it has not started to drop off by the 9th.  The calculated THD is based on only those four frequencies, it should be easy to imagine that if you calculated more components the THD would keep going up.

How many do you need?  To get an idea, look at the width of your distortion pulse, 10us in your example.  It's a good bet that the 'missing' pulse has components up to at least 100kHz.  So you may need to go past the 99th harmonic to get anything accurate.  Or, remove the fundamental and measure the RMS of what remains, much easier.

Once this is understood it's easy to see why your observation came out too low (not enough coefficients included in the measurement) and also why the observed exponent is too high (as D increases the number of important coefficients will be reduced, so the THD will not increase as fast as you observed, exponent of 1.5 instead of 2).

HTH,
  Fred

Show quoted text

--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:

Hello Echidna,

Crossover Distortion
--------------------

I calculated the formula with Fourier series and approximation.

sin(x) = x-1/3*x^3

1-x^2 = 1-2*x

THD = 100%*2*pi*sqrt(1/3*(D/T)^3)
=================================

Files > Temp > crossover_distortion.asc

You can check the distortion calculated by .FOUR with
View -> SPICE Error log

Best regards,
Helmut


--- In LTspice@..., "Echidna" <mchambin@> wrote:

Hello.
How to calculate, using maths and definitions, the THD of this signal: A sine with a small dent at the  crossovers.

S(t) = 0 for 0 < t < D where D is much smaller than T
S(t) = sin omega*t for D < t < T/2 where omega is 2*pi/T
S(t) = 0 for T/2  < t < T/2 + D
S(t) = sin omega*t for T/2 + D < t < T

Using LTspice simulations I find THD = 25*( D/T )^2
In this simulation I used a 1000 HZ SINE combined with a PULSE with values of D like 0.1u 0.2u 0.5u 1u 2u 5u 10u 20u 50u
These simulations gave me a THD that perfectly fits with 25*( D/T )^2

Here is the issue.
I was enable to prove this result with maths
(instead of simulations ).
I started computing the RMS value of the error signal (the dents at the crossovers)
With sin omega*t = omega*t ( valid for t << T )
I don' t get the 25*( D/T )^2 result, I do get a fonction of D/T, so far so good, but I don't get the right exponant. It seems my approach is wrong.

Is there a signal theory / maths guru who can give the proof that for such a signal S(t) ( with D << T ) we have  THD = 25*( D/T )^2

Re: High-power Infrared LED model desired

John Woodgate

#62677

In message <kkf3is+3juc@...>, dated Sun, 14 Apr 2013, Helmut <helmutsennewald@...> writes:

N=     1.570213683
+      RS=     0.762136823
+      IKF=    392.8188163Not Helmut's responsibility, but isn't it disquieting that these are given to 10 significant figures? Doesn't inspire confidence. Can we sue if IKF turns out to be 392.8188162?(;-)
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Things to do today: Cut a hole in reality and push a turnip through.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: High-power Infrared LED model desired

#62676

--- In LTspice@..., "nedkonz" <ned@...> wrote:

Hi folks,

I'm trying to model an infrared remote control transmitter circuit that I'm designing and haven't had much luck finding a SPICE model for the higher-power IR LEDs like I'm using.

In this case, I have the OSRAM SFH4248 940nM emitter, and their site doesn't have any models for their IR LEDs.



I've also looked in the files area here without any luck.

Could anyone point me to a model for this diode?

Thanks!

Hello,

The model for the OSRAM SFH4248 is in the file
OSRAM-IR-POWERTOPLED.lib




.MODEL SFH4248 D
+	IS=	1.50099E-15
+	N=	1.570213683
+	RS=	0.762136823
+	IKF=	392.8188163
+	IBV = 	0.00000001
+	NBV =	1
+	IBVL =	0.000000001
+	NBVL =	180
+	BV =	24
+	CJO =	1.46E-11
+	VJ =	0.56
+	M =	0.055
+	FC =	0.4
+	TT =	0.000000008
+	EG =	1.3


Best regards,
Helmut

High-power Infrared LED model desired

#62675

Hi folks,

I'm trying to model an infrared remote control transmitter circuit that I'm designing and haven't had much luck finding a SPICE model for the higher-power IR LEDs like I'm using.

In this case, I have the OSRAM SFH4248 940nM emitter, and their site doesn't have any models for their IR LEDs.

I've also looked in the files area here without any luck.

Could anyone point me to a model for this diode?

Thanks!

Re: All_Files.Htm

John Woodgate

#62674

In message <759B589F6950452C8C99FA8446748D7E@Maison3>, dated Sun, 14 Apr 2013, basier. philippe <basier.philippe@...> writes:

But you wrote that you have had the same problemYes, I did have the problem a few weeks ago, and at that time, I think, everyone (more or less) did. The problem went away after a week or two, with no explanation, as far as I know.
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: All_Files.Htm

#62673

Hello Philippe,

I am using at the moment a PC with XP. I can directly open
all_files.htm without saving it. I checked with Firefox,
IE and Chrome. All three worked as expected.

Best regards,
Helmut

Show quoted text

--- In LTspice@..., "basier.philippe" <basier.philippe@...> wrote:

Dear Helmut,
I can only dowload it and open the dowloaded file. I did it .
I can't open it from my browser (IE).
Regards,
Philippe
  ----- Original Message -----
  From: Helmut
  To: LTspice@...
  Sent: Sunday, April 14, 2013 8:21 PM
  Subject: [LTspice] Re: All_Files.Htm





  --- In LTspice@..., "Basier philippe" <basier.philippe@> wrote:
  >
  > Hello
  > How to open all_files.htm ?
  > Regards
  > Philippe
  >

  Hello Philippe,

  You should open it with any Internet browser.

  IE, Firefox, Chrome, Opera, ...

  Normally it's automatically opened by your standard browser
  when you click on it.

  Files > Tables of Contents > all_files.htm

  Best regards,
  Helmut





[Non-text portions of this message have been removed]

Re: All_Files.Htm

John Woodgate

#62672

In message <913832DA74584FFFB1B82295C5FF0858@Maison3>, dated Sun, 14 Apr 2013, basier. philippe <basier.philippe@...> writes:

I can only dowload it and open the dowloaded file. I did it .
I can't open it from my browser (IE).It should: it does on my computer. Which version of IE do you have? I have IE8 on this computer. Do you have McAfee anti-virus? I don't.
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Things to do today: Cut a hole in reality and push a turnip through it.
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: Bridge current sensor INA193 or AD8210 available?

#62671

--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:

--- In LTspice@..., "mario.haselsteiner" <mario.haselsteiner@> wrote:

Hello,

is there anywhere a model for a bridge current sensor available for downloading?

Thanks
Mario

Hello Mario,

There is an example with the AD8210 in the Files section.

Files > Lib > AD8210_test.zip

Best regards,
Helmut
Hello Mario,

I just made the missing INA193 example.

Files > Lib > INA193_test.zip

It's best practice to copy the model file and the symbol
file into the folders where you have the schematics.

Best regards,
Helmut

Re: All_Files.Htm

#62670

But you wrote that you have had the same problem
Philippe

Show quoted text

----- Original Message ----- 
  From: John Woodgate 
  To: LTspice@... 
  Sent: Sunday, April 14, 2013 8:50 PM
  Subject: Re: [LTspice] Re: All_Files.Htm


    
  In message <kket93+h2gb@...>, dated Sun, 14 Apr 2013, sawreyrw 
  <sawreyrw@...> writes:

  >
  >It doesn't work for me either. You need to download it to your C 
  >drive, and then you will be able to open it with your browser.

  This suggests (not very strongly though) that a browser or anti-virus 
  security setting is stopping it being opened directly. The other 
  explanation is, of course, the Principle of Universal Perversity.
  -- 
  OOO - Own Opinions Only. See www.jmwa.demon.co.uk
  They took me to a specialist burns unit - and made me learn 'To a haggis'.

  John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: All_Files.Htm

#62668

Rick,
Yes ,
I did it. But it's not handy think about updates oh all_files.
I don't use my drve C: for dowloading ot installations. Even LTspice IV !
Thanks
Philippe

Show quoted text

----- Original Message ----- 
  From: sawreyrw 
  To: LTspice@... 
  Sent: Sunday, April 14, 2013 8:41 PM
  Subject: [LTspice] Re: All_Files.Htm


    


  --- In LTspice@..., "Basier philippe" <basier.philippe@...> wrote:
  >
  > Hello
  > How to open all_files.htm ?
  > Regards
  > Philippe
  >

  Philippe,

  It doesn't work for me either. You need to download it to your C drive, and then you will be able to open it with your browser.

  Rick

Re: All_Files.Htm

John Woodgate

#62669

In message <kket93+h2gb@...>, dated Sun, 14 Apr 2013, sawreyrw <sawreyrw@...> writes:


It doesn't work for me either.  You need to download it to your C drive, and then you will be able to open it with your browser.This suggests (not very strongly though) that a browser or anti-virus security setting is stopping it being opened directly. The other explanation is, of course, the Principle of Universal Perversity.
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: All_Files.Htm

#62667

Dear Helmut,
I can only dowload it and open the dowloaded file. I did it .
I can't open it from my browser (IE).
Regards,
Philippe

Show quoted text

----- Original Message ----- 
  From: Helmut 
  To: LTspice@... 
  Sent: Sunday, April 14, 2013 8:21 PM
  Subject: [LTspice] Re: All_Files.Htm


    


  --- In LTspice@..., "Basier philippe" <basier.philippe@...> wrote:
  >
  > Hello
  > How to open all_files.htm ?
  > Regards
  > Philippe
  >

  Hello Philippe,

  You should open it with any Internet browser.

  IE, Firefox, Chrome, Opera, ...

  Normally it's automatically opened by your standard browser
  when you click on it.

  Files > Tables of Contents > all_files.htm

  Best regards,
  Helmut

Re: All_Files.Htm

#62665

--- In LTspice@..., "Basier philippe" <basier.philippe@...> wrote:

Hello
How to open all_files.htm ?
Regards
Philippe
Philippe,

It doesn't work for me either.  You need to download it to your C drive, and then you will be able to open it with your browser.

Rick

Re: All_Files.Htm

#62666

Hello John,
I can only dowload it and open the dowloaded file. I did it .
I can't open it from my browser (IE).
Regards

Show quoted text

----- Original Message ----- 
  From: John Woodgate 
  To: LTspice@... 
  Sent: Sunday, April 14, 2013 8:18 PM
  Subject: Re: [LTspice] All_Files.Htm


    
  In message <kker0j+82e6@...>, dated Sun, 14 Apr 2013, Basier 
  philippe <basier.philippe@...> writes:

  >How to open all_files.htm ?

  Has it gone wrong again? It should open in any browser.

  I just tried it and it opens OK. But it is a very large HTML file, so it 
  may take time to download, or be corrupted during download.
  -- 
  OOO - Own Opinions Only. See www.jmwa.demon.co.uk
  They took me to a specialist burns unit - and made me learn 'To a haggis'.

  John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Re: Bridge current sensor INA193 or AD8210 available?

#62664

--- In LTspice@..., "mario.haselsteiner" <mario.haselsteiner@...> wrote:

Hello,

is there anywhere a model for a bridge current sensor available for downloading?

Thanks
Mario

Hello Mario,

There is an example with the AD8210 in the Files section.

Files > Lib > AD8210_test.zip

Best regards,
Helmut

Re: All_Files.Htm

#62662

--- In LTspice@..., "Basier philippe" <basier.philippe@...> wrote:

Hello
How to open all_files.htm ?
Regards
Philippe

Hello Philippe,

You should open it with any Internet browser.

IE, Firefox, Chrome, Opera, ...

Normally it's automatically opened by your standard browser
when you click on it.

Files > Tables of Contents > all_files.htm

Best regards,
Helmut

Re: All_Files.Htm

John Woodgate

#62663

In message <kker0j+82e6@...>, dated Sun, 14 Apr 2013, Basier philippe <basier.philippe@...> writes:

How to open all_files.htm ?Has it gone wrong again? It should open in any browser.

I just tried it and it opens OK. But it is a very large HTML file, so it may take time to download, or be corrupted during download.
-- 
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
They took me to a specialist burns unit - and made me learn 'To a haggis'.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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