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Linear LED driver - two BC847C's seem to be useless?

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eem2am

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linear current regulator led

hello

please can you confirm that this LED driver is erroneous?

10qfhw9.jpg


https://i30.tinypic.com/10qfhw9.jpg

it runs off a 13V battery.

The LMV431 is getting feedback from just one of the emitters. This seems wrong and not useful.

https://www.national.com/ds/LM/LMV431.pdf

(page 14 details the current regulator usage of LMV431)

In practice , we find that the circuit on the PCB gives an oscillation of 2V peak to peak on the collector of the FMMT619 BJT's.

We can solve this by putting on a few 10nF caps from base to emitter of a few of the FMMT619's.

But anyway, i think it is erroneous, do you?..those two BC847C's seem to be doing nothing useful ?

Though the circuit does work - i feel it is using more components than necessary?

please could you comment?
 

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