An ultra low power maximum voltage detector for piezoelectric and electrostatic energy harvesters

This paper presents an integrated circuit for mechanical energy harvesting applications which detects the electromechanical converter´s maximum voltage in a very low power way. This circuit has been designed in AMS 0.35μm CMOS technology and its functionality and its efficiency have been validated with different kinds of converters (piezoelectric and electrostatic) at various mechanical frequencies (from 1 to 200 Hz). The experimental results have shown a power consumption of 150 nW under 3V with a delay of detection lower than 50μs. This circuit appears to be a relevant solution for all Application-Specific Integrated Circuits (ASIC) in which the harvesting methods are based on Synchronized Switch Harvesting techniques (SSH).