A thermoelectric power supply converts thermal energy into a high power output with voltages in the Volt-range for powering a microelectronic device and comprises an in-plane thermoelectric generator, a cross-plane thermoelectric generator, an initial energy management assembly, a voltage converter and a final energy management assembly. The in-plane thermoelectric generator produces a high thermoelectric voltage at low power output. The initial energy management assembly rectifies and limits the thermoelectric voltage and stores and releases power to the voltage converter. The cross-plane thermoelectric generator generates a high power output at low thermoelectric voltage. Once activated by the in-plane thermoelectric generator, the voltage converter multiplies the low thermoelectric voltage output of the cross-plane thermoelectric generator. After multiplying the relatively low voltage provided by the cross-plane thermoelectric generator, the voltage converter supplies electrical energy to the final energy management assembly which rectifies and limits the voltage and stores and releases energy to an external power receiver such as the microelectronic device.