Back side power supply for electronic devices

A semiconductor device comprising:

• a first semiconductor die comprising a plurality of transistors, wherein the first semiconductor die is arranged over a package substrate or a circuit board;
• a second semiconductor die comprising power supply circuitry configured to generate a supply voltage for the plurality of transistors of the first semiconductor die;
• and
• a heat spreader structure arranged over the second semiconductor die,
• wherein a first power supply routing for a reference voltage or a power supply voltage extends from the heat spreader structure to the first semiconductor die and the second semiconductor die, and a second power supply routing for a reference voltage or a power supply voltage extends from the package substrate or the circuit board to the second semiconductor die through a path that is physically separate from the heat spreader structure.