A fully-integrated, high-conversion-ratio and dual-output voltage boost converter with MPPT for low-voltage energy harvesting

This paper proposes a fully-integrated high-conversion-ratio dual-output voltage boost converter (VBC) with maximum power point tracking (MPPT) circuits for low-voltage energy harvesting. The VBC consists of two voltage generators that generate V_OUT1 and V_OUT2. V_OUT1 and V_OUT2 are three and nine times higher than the harvester´s output Vin, respectively. V_OUT1 is used as a supply voltage for on-chip application circuits while V_OUT2 is used as the charging voltage for a Li-ion battery. The VBC achieves a high voltage conversion ratio (max. × 9) and a high power conversion efficiency with a small number of charge pumps (CPs). The MPPT circuits control the operating frequencies of the CPs to extract maximum power at each output. The measurement results demonstrated that the circuit converted a 0.59-V input to a 1.41-V output with 75.8% efficiency when the output powers of V_OUT1 and V_OUT2 were 396 and 0 μW, respectively, and a 0.62-V input to a 4.54-V output with 49.1% efficiency when the output powers were 0 and 114 μW, respectively.