I need to boost 3V to 20V (<1A) for use in a current source. I need a very small solution for my portable device. Most boost converters I find seem to not operate at at very low output currents.
The current source will be pulsed at 100-1000ms intervals with 1-2ms duration with amplitudes between 1-100 uA. My load is biological tissue and may range from 50-500 kOhms.
What would be the best way to generate <1mA at 20V?