MEMS-switch-based power management with zero-power voltage monitoring for energy accumulation architecture on dust-size wireless sensor nodes

A power management scheme using a MEMS switch is proposed as a way to accumulate charge even when the energy-harvesting device generates minute current of <;10 pA. Voltage monitoring does not consume any power at all. A node prototype powered by the MEMS switch is implemented. Test chips were fabricated using the 0.35-μm CMOS process and MEMS process. The MEMS-switch power management operation and wireless node operation with nanowatt vibration sensing are confirmed.