LM334z

[StoneT]

Here's a spreadsheet that some people may find helpful. It calculates the resistors required to set the current of an LM334 CCS with and without the temperature compensating diode. I did this to avoid using the bizzarely complicated and backwards way the literature sets out
Notes:
Change the .txt extension to .xls and open with Excel. It's the only way i could attach it (Why can we not post .xls files?)
Set required current in the blue box (B3) to use
It is only of reasonable accuracy for currents of 1 mA to 10 mA. this is due to the approximation of the n ratio (Iset to Ibias).
Vf of the diode has been defaulted to 0.6V. You can normally improve on the accuracy of this from the diode's datasheets, looking at the Vf/If charts.
Diode thermal coeficient of Vf has been assumed as 2mV/K.

If anyone has any suggestions they would be most welcome.
I also have a sheet that gives you Iset for given values of R1 and R2 which may be helpful to tell how well standard values fit.

[StoneT]

Oops, minor correction.
and you can now enter the diodes tempco.

Again, change .txt for.xls

[StoneT]

I should also have said that this is experimental and has not been put to the test. If you use it and it's wrong don't blame me.
If you do have info to compare it with please tell me if it's right or wrong.

THX

[StoneT]

Final Version!

Added the other tables so you can experiment with reisistor values. These also give you the resulting TempCo for the CCS.
As before change .txt for .xls for it to work.

All feedback appreciated.

[jackinnj]

Originally posted by StoneT

Change the .txt extension to .xls and open with Excel. It's the only way i could attach it (Why can we not post .xls files?)

Probably becuz some XLS files contain macros.

(Back in the early days of Excel (pre-Windows) I used macros to develop a bond pricing system -- I had to do this as the traders I worked could either used a Monroe Bond Calculator or their fingers to determine yields.) You can put some nasty stuff in an Excel Macro.

[StoneT]

:thinks: Oh no! He's close to discovering my evil plot to gain control of audiophile computers...

But seriously, am I not supposed to post these incognito files then?

[StoneT]

OK, realy last one this time. Locked some of the wrong cells on ver. 3 so, not hearing any opposition, Here is LM334zV4.XLS
(I just noticed we can post .zip files too, which kind of means you can post anything )