Different solutions have been recently proposed in numerous papers. Maximum Power Point Tracking (MPPT) has an important role in studying and implementing

Anyhow, simulations and measurements both confirm that the presented silicon-proven comparator topology is capable of reliable operation with power consumption within nW range.

An excellent correlation between simulations and the measured bench data has been observed with the supply voltage value of 0.6 V, while slightly less tight correlation has been reported for VDD = 0.4 V. The measurement results obtained from fabricated prototype chips, including static and dynamic parameters, are presented and discussed as well. So-called gm/ID low-voltage design methodology in combination with the bulk-driven design approach have been selected in the circuit topology. The comparator is intended to be employed in an on-chip energy harvester system with minimized quiescent current consumption. The comparator can handle the input voltage within rail-to-rail range and is capable of working in temperature range from −20 to 85 ☌ and with power supply voltage as low as 0.4 V. This paper presents a performance evaluation of an ultra low-voltage non-clocked voltage comparator, designed and fabricated in a standard twin-well 130 nm CMOS technology. From measurements we verify all the key merits of this design: (i) a high voltage converting efficiency (up to 97.1%) of the rectifier (ii) a minimum of 102 s charging time to charge a 1 mF supercapacitor from 0 V to 3.3 V of the buck-boost converter with impedance matching method (iii) a 10 nA to 100 μA load current range and at least 85° phase margin (PM) LDO regulator with ultra-low quiescent bias current as low as 750 pA. The chip is fabricated using 0.5 μm standard CMOS process. A buck-boost converter, as an impedance matching converter to achieve MPPT, further transfers the energy into a supercapacitor, from which a low-dropout (LDO) regulator powers an on-chip CMOS sensor with clean power supply. Firstly, a piezoelectric (PZE) transducer scavenges and transforms mechanical vibration energy into electricity, which is then converted into DC power by a rectifier and collected into a small filter capacitor. This paper presents an ultra-low quiescent current power management system that interfaces with energy harvester and thus enables self-powering, battery-less wireless sensors.

Ultra low battery tracker chip