An 88% efficiency MPPT for PV energy harvesting system with novel switch width modulation for output power 100nW to 0.3mW

Abstract

This paper presents a novel three-dimensional maximum power point tracking (3D-MPPT) system for ultra-low power (ULP) solar energy harvesting systems (EHS) for internet of things (IoT) smart nodes. The proposed 3D-MPPT utilizes a gate-source voltage (V gs ) dependent switch width modulation (SWM) technique for improving power efficiency (PE) at standby ( 300μA) load scenarios, and eliminating the gate driver and conduction loss trade-off for a reconfigurable switched capacitor charge pump (SCCP). The proposed SWM technique modulates the SC transistors size in proportion to the load condition, input voltage and V gs applied. The tested chip, fabricated in 65-nm CMOS technology, can harvest from 0.35 V and provides a regulated output voltage at 1 V with peak efficiency of 88% at 200 μW and PE > 60% at 100 nW.