What is the best way to balance supercapacitor cells at 700mA peak charging current
TLV431+powerBJT would be my favourite as well (note the V in TLV).

However, you might find a colour of LED for which LED+powerBJT gives a voltage in your desired window with fewer components, albeit with a less sharp current knee and wider tolerance.

Another common way to get a high power low voltage shunt reference is this, again the knee is not as sharp as when using a TLV431, but your specifications on voltage tolerance seem to allow for that. It doesn't meet leakage at low voltage, but replacing R2 with series silicon diodes might work. It's still a higher component count than you want.







simulate this circuit &ndash; Schematic created using CircuitLab