My first question here:
I want to make a simple adjustable current supply for some LEDs I have (approx 3 V and up to 3 amps). I've decided against just using a single FET to control current as it would have to dissipate as much as 9 W of heat. For such a circuit I don't mind a bit of ripple (above say 10 kHz) in the current since its driving an LED which is driving phosphors anyway (the LEDs are white).
I'm not a power engineer so I have the question:
Would the circuit below (which I pulled from my behind) work? I haven't seen anything too similar online. Aside from some ripple equal to whatever the hysteresis (divided by R1) are there any problems? Are there concerns with setting the right oscillation frequency? Should I choose component values to target a specific frequency (I was just going to go with >20 kHz in case something vibrates)?