I need programmable current control, fading from zero to 2 milliAmps. I was hoping to use Arduino's AnalogWrite(), which uses Phase Width Modulation (PWM) to simulate analog output with a sawtooth wave on a duty-cycle; to control an LM334Z to deliver a slowly ramped low current delivery. [The application is a TransCranial Direct Current Stimulation (TDCS) micro-current delivery to the human scalp. Jumping straight to 2 milliAmps is uncomfortable]. Will PWM work? Or, do I need some sort of smoothing circuitry to soften the PMW before it is applied to the LM334Z's Rset pin to accomplish the above?
LM334Z's Rset pin to accomplish the above?
Most of that type of circuit has its operations be determined by the current In or out of that pin. So a voltage signal may not work - you will need to experiment. I have had some success with analogs dds chips and linear programmable osscillators.
So try it on your chip. Nothin to lose.