A card with power management circuitry is provided. A card may have circuitry contained therein (e.g., a processor) that may have a maximum operating voltage. The card may include a power source (e.g., a battery) that provides power ranging in voltage from a maximum power source voltage to a minimum power source voltage. The maximum power source voltage is greater than the maximum operating voltage. Power management circuitry is provided to manage the power received from the power source such that the voltage provided to the circuitry (e.g., processor) does not exceed the maximum operating voltage.