Hi ... thanks for posting my re-working of your circuit Roly
if I may, I'd like to provide a second version of my adaptation as the first one produced a "hung" LED // we suspect on account of an overly high voltage seen at the driver pins ...
a simple solution to bringing that voltage down simply involves including a common-base stage (BD139) to buffer the high voltage coming from the mirror input // in principle this does not change the overall operation of the circuit since the current gain is very close to unity in the new stage ...
I will say that the temperature range adjustments (as drawn in my version) and current gain adjustment in the mirror all worked like a charm ...
// ~jc
if I may, I'd like to provide a second version of my adaptation as the first one produced a "hung" LED // we suspect on account of an overly high voltage seen at the driver pins ...
a simple solution to bringing that voltage down simply involves including a common-base stage (BD139) to buffer the high voltage coming from the mirror input // in principle this does not change the overall operation of the circuit since the current gain is very close to unity in the new stage ...
I will say that the temperature range adjustments (as drawn in my version) and current gain adjustment in the mirror all worked like a charm ...
// ~jc