Using a Supercapacitor to Power Wireless Nodes from a Low Power Source such as a 3V Button Battery

Portable and remote data gathering systems often need to be powered from small long life batteries and are required to transmit data sporadically. GPRS RF transmitters typically operate at a minimum voltage of 3.2 Volts and draw pulsed currents in the order of 1 to 2 Amps. Zigbee typically requires 10 - 100 mA transmit current from a 3 V battery. These peak load powers are too great to be supplied by small long life batteries such as a CR2032, even though the battery can supply the average system power. This paper offers a solution using a single cell supercapacitor to supply the peak loads with low cost circuitry. A single cell supercapacitor cannot operate at 3 V, but does not require a balancing circuit and is lower cost and half the size of a dual cell supercapacitor required for 3 V operation.