Hi all,
I'm looking for a way to make a circuit that will limit the output current between around 20 and 500mA (200mA will do if it really can't be done). It could be controlled either with a serial interface, a pwm signal, digital parallel signal, analog signal, etc, as long as it's controllable with a microcontroller.
Usually I would use a LM317 with a rheostat, but I want to get rid of the rheostat. I looked into using digital potentiometers, but the maximum continuous current is always around 5mA or less, which is way too little.
I also looked into using a resistor ladder, but I think it's a bit of a bulky solution for something that should be possible otherwise.
The circuit should be able to work at different output voltages between 2 and 5 volts, though it would be acceptable if the components had to be calculated for a fixed voltage or if the system had to be recalibrated for each voltage...