SPICE simulation of ultra low voltage step up converter. This DC-DC converter is ideal to manage energy from ultra low input sources as thermoelectric generators, small solar cells, where the input voltage is of the order of a few tens of mV. The harvested energy is sent to Vout, the harvested energy in excess is sent to Vstore that will supply Vout when the input is unavailable. The 2.2V LDO powers an external microprocessor. Vout2 is switched output for sensors without a shutdown capability. Typical applications are low power wireless sensors and surplus energy harvesting applications.