An LED package containing integrated circuitry for matching a power source voltage to the LED operating voltage, LEDs containing such integrated circuitry, systems containing such packages, and methods for matching the source and operating voltages are described. The integrated circuitry typically contains a power converter and a constant current circuit. The LED package may also contain other active or passive components such as pin-outs for integrated or external components, a transformer and rectifier, or a rectifier circuit. External components can include control systems for regulating the LED current level or the properties of light emitted by the LED. Integrating the power supply and current control components into the LED can provide for fabrication of relatively small LEDs using fewer and less device-specific components.