A power management and computation methodology is proposed for ultra-low power energy harvesting applications. 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 cater with the fluctuated energy source and unregulated power supply, a supply side charge-based computation methodology is proposed, of which the computation activity tracks with the fluctuation of the available energy. The idea is demonstrated in a test chip fabricated using a 0.35 mum technology