Energy-Harvesting Power Supplies

A switch mode power supply comprising:

• a power converter circuit comprising a first transformer having a first primary winding, a first secondary winding and a first magnetic core shared therebetween;
• a transistor switch having a drain electrically connected to the first primary winding and a source electrically connected to ground;
• and
• an energy-harvesting circuit configured to harvest energy from the power converter circuit, the energy-harvesting circuit electrically connected to the transistor switch and comprising:
• a second transformer having a second primary winding, a second secondary winding and a second magnetic core shared therebetween, wherein the second primary winding is electrically connected between the drain and the source of the transistor switch;
• a coupling capacitor electrically connected between the drain and the second primary winding and configured to provide a reset mechanism for the second magnetic core in the second transformer;
• a diode having an anode and a cathode, the anode electrically connected to the second secondary winding;
• and
• a capacitor electrically connected in series with the cathode of the diode and in parallel with load circuitry.

An energy-harvesting circuit configured to harvest energy from a power converter circuit within a switch mode power supply, the energy-harvesting circuit comprising:

• means for transferring excess electromagnetic energy from a transistor switch electrically connected to the power converter circuit to a magnetically isolated clamp circuit;
• means for storing the excess electromagnetic energy in the magnetically isolated clamp circuit;
• and
• means for powering a load circuitry by referencing the stored excess electromagnetic energy to a ground.