title: A 66pW Discontinuous Switch-Capacitor Energy Harvester for Self-Sustaining Sensor Applications.
abstract: We present a discontinuous harvesting approach for switch capacitor DC-DC converters that enables ultra-low power energy harvesting. By slowly accumulating charge on an input capacitor and then transferring it to a battery in burst-mode, switching and leakage losses in the DC-DC converter can be optimally traded-off with the loss due to non-ideal MPPT operation. The harvester uses a 15pW mode controller, an automatic conversion ratio modulator, and a moving sum charge pump for low startup energy upon a mode switch. In 180nm CMOS, the harvester achieves >40% end-to-end efficiency from 113pW to 1.5μW with 66pW minimum input power, marking a >10× improvement over prior ultra-low power harvesters.
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wu
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Yao
authors.initials: Y
authors.lastname: Shi
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Supreet
authors.initials: S
authors.lastname: Jeloka
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Kaiyuan
authors.initials: K
authors.lastname: Yang
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Inhee
authors.initials: I
authors.lastname: Lee
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: Dennis
authors.initials: D
authors.lastname: Sylvester
authors.affiliation: University of Michigan, Ann Arbor, MI.
authors.forename: David
authors.initials: D
authors.lastname: Blaauw