Hello everybody, I'm working on a T.E.N.S. unit that has a maximum output voltage of 30Vpp (constant), my current system can generate different waveforms such as rectified sine wave, square wave, biphasic square wave, etc. Taking into consideration that the output voltage is "fixed" I want to regulate the output current from 0 up to 150 mA. The problem is that I dont have any idea about how to solve it, since I want to digitally control. I thinking in using a V to I converter but I don't really sure if it is going to work with huge Rload (human skin >~1Mohm). So any idea is highly appreciated. Thanks in advance.