Does anyone know if it's possible to connect the feedback pin of a DC-DC boost converter chip like Texas Instruments' LM2733 in a different manner than the one described in the datasheet, namely on the collector of the output side of a standard BJT current mirror, like so :
In which case
With Vfb=1.23V for this specific chip.
This would allow minimizing losses in Q2 by setting Vce a little bit above 0.7V, without having to know the exact voltage of the LED string at a given current.
However I'm way out of my depth here, so I'm wondering :
- Is this worth trying?
- Is there a risk that the chip will go berserk due to the nonlinearity of Vce as a function of the voltage across the load?
- Where should the forward compensation capacitor be connected? What should its value be?
Thank you very much.