Other Parts Discussed in Thread: BQ24640, LM5022
I am curious if controlling the SHDN pin of the LM2842 can allow it to be used as a constant-current source. I'm thinking in particular of an LED driver (where the voltage target would be set above the LED Vf and SHDN would be used to set the LED current), or a supercap charger, where the voltage target would be the target cap voltage (2.7V, for example) and SHDN would set a maximum current so that the empty cap does not effectively short out the supply.
The difference between these two is that the LED case would never actually use the voltage regulation but would always operate in a current-limited mode. For the supercap charger you would eventually hit the target voltage and the current would drop below the maximum (as set by SHDN) as you approached the target voltage.
It looks like the SHDN pin will allow you do this but I want to make sure I'm not overlooking anything. The fact that the relationship between SHDN and current might not be accurate or linear is not a major concern, at least not at the moment.
I would be interested if you had any other parts to recommend as well, perhaps something that is explicitly designed for these roles? I have looked at dedicated supercap chargers like the BQ24640 but one major issue with that is that I need a higher Vin max, and the 42V for the LM2842 would work well.
