A novel charge based computation system is proposed for ultra low power applications based on energy harvesting. An integrated exponential charge pump that accepts an input voltage of around 150mV and provides an unregulated output voltage of more than 1.5V serves as the power supply. To track with the unregulated voltage supply, a supply side charge-based computation methodology is proposed. Charge based control strategy is further derived to efficiently use the harvested energy and to increase the number of computations during a certain time interval. The suggested system and control strategy are demonstrated in a test chip fabricated using a 0.35/spl mu/m technology.