Design and optimization of a Vibrational MEMS-Based Energy Harvester

Analysis and Design of a Self-Powered VEH System Based on ULP Comparator

“…It must be pointed out that the comparison between harvester circuits is problematic since several factors must be considered, such as MEMS type, harvester area, bandwidth, and operating acceleration. Among the types of harvester circuits, we can find switching that can be electronic, usually implementing a comparator [10,13,15,16], or mechanical using a MEMS to generate the intermittent signal that charges the load capacitor [14]. The mechanical structure has lower power consumption since it does not necessarily need current to operate although the implementation becomes more complicated.…”

“…Therefore, the inversion of the MOS devices used is limited to a weak inversion (subthreshold). This design strategy has been previously implemented in [10][11][12], showing promising results for ultra-low power applications. The bulk-driven input stage effectively eliminates the threshold voltage problem of the MOS devices and allows rail-to-rail operation [10].…”

“…This design strategy has been previously implemented in [10][11][12], showing promising results for ultra-low power applications. The bulk-driven input stage effectively eliminates the threshold voltage problem of the MOS devices and allows rail-to-rail operation [10]. Devices Mi1 and Mi2 act as constant current sources whose amount of static current is being modulated by the input voltage according to the body effect phenomenon.…”

“…This voltage-to-current conversion occurs linearly, since the transconductance is almost perfectly constant over the entire specified voltage range. In addition, there is no internal bias reference in the circuit, which simplifies the design procedure and reduces the total current consumption [10]. Fig.…”