The major obstacle in the commercialization of vibration energy harvesters in wearables has been that, simply put, piezoelectric harvesters’ output voltages are too high and electromagnetic harvesters’ output voltages are too low. This has motivated Creathadh Energies inventions. The issue with piezoelectric harvester’s output voltages is that for this application they typically range between 5-10V and can go significantly higher. This means they are not suitable for low voltage CMOS circuits. For example, a 1.8V 180nm CMOS process will likely have a significant ESD event when hit with ~10V. For example, piezoelectric harvesters built for shoes typically have output voltages over 10V and as high as 100V. CMOS technologies such as 180nm, 130nm, or 90nm are mature, accessible, inexpensive and can be designed for very low-power applications (<1 µW). These technologies are part of what is driving the low-power wearables revolution. However, they typically have maximum voltage limits of, at most, ~3V.

In contrast to piezoelectric harvesters, a typical electromagnetic harvester output is often under 0.4V, and these outputs were not be able to overcome the diode drops of a CMOS-based half or full-wave rectifier to just start-up and turn on a CMOS circuit. That is, not until Creathadh’s technology was invented, which allowed start-up at a record low voltage.