A 400nW single-inductor dual-input-tri-output DC-DC buck-boost converter with maximum power point tracking for indoor photovoltaic energy harvesting

Chew, Kok Wai; Sun, Zhuochao; Tang, Haihan; Siek, Liter

doi:10.1109/isscc.2013.6487640

Cited by 32 publications

(33 citation statements)

References 3 publications

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“…Switched inductors in [20], [22], and here may sacrifice board space for one off-chip inductor, but they also draw hundreds of microwatts with more than 60% efficiency. Although conversion efficiencies in [20], [22], and here are largely comparable, [20] does not regulate its output, and the output ripple in [22] grows substantially with load current. And without regulation, [20] must enlist a regulator to supply the load, the additional losses of which reduce efficiency.…”

Section: Contextmentioning

confidence: 99%

“…Even though the controller consumes more power at 3-30 µW (for better regulation) than [22] does at 400 nW, conversion efficiency is nevertheless 3%-5% higher. This is because the power stage is more efficient across PV and load power, and system components operate only when needed.…”

Section: Contextmentioning

confidence: 99%

“…This is because the power stage is more efficient across PV and load power, and system components operate only when needed. Plus, [22] draws battery power when PV power is sufficient to supply the load. This means, the system transfers PV energy twice, first from the cell to the battery and then from the battery to the load, so losses are greater and efficiency is lower.…”

Section: Contextmentioning

confidence: 99%

“…Unlike in [22] and [23], which also draw battery assistance, the system presented here draws assistance only when the PV cell cannot supply the load, which saves battery energy. Plus, when drawing assistance, this system still supplies PV power to the load directly, so battery assistance is lower and the savings is greater.…”

Section: Contextmentioning

confidence: 99%

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0.18-μm Light-Harvesting Battery-Assisted Charger–Supply CMOS System

Prabha

Rincón-Mora

2016

IEEE Trans. Power Electron.

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Wireless microsensors in hospitals, factories, and farms can manage and save lives and critical resources. Although tiny batteries cannot sustain them for long, harvesters can because ambient energy is abundant. Photovoltaic cells are popular in this regard because they output close to 100× more power from solar light than piezoelectric, electrostatic, and thermoelectric generators can from motion and heat. But since millimeter cells can only supply microwatts of the milliwatts that microsystems can draw, and light is not always available, battery assistance is necessary. So to supply functions and sustain operation across extended periods, the system should extract maximum ambient power, draw minimal battery assistance, and deliver as much of what it receives as possible. The 0.18-µm CMOS harvester presented here does this, draws 10-100 µW from a 3 × 3 × 1-mm 3 cell and assistance from a battery to supply a 1-mW load and recharge the battery with excess cell power. The switched-inductor charger-supply regulates 1-V within ±25 mV with 73%-86% power-conversion efficiency and keeps the cell within 1% of its maximum power point. This way, the cell outputs 100 µW/mm 2 from solar light and 1 µW/mm 2 from direct indoor light.Index Terms-Ambient light energy, harvester, CMOS photovoltaic (PV) cells, microsystem, switched-inductor converter, wireless microsensor, charger, and power supply.

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Section: Contextmentioning

confidence: 99%

Section: Contextmentioning

confidence: 99%

Section: Contextmentioning

confidence: 99%

Section: Contextmentioning

confidence: 99%

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0.18-μm Light-Harvesting Battery-Assisted Charger–Supply CMOS System

Prabha

Rincón-Mora

2016

IEEE Trans. Power Electron.

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“…They are manufactured in the nm scale CMOS technology, enabling nA or µA sleep current with [24,25] or without [26,27] implemented MPPT technique. There are also commercial ICs dedicated to indoor light harvesting which operate with low input/start-up voltage, implement MPPT technique and have low quiescent current [28].…”

Section: Introductionmentioning

confidence: 99%

Photovoltaic Energy Harvesting Wireless Sensor Node for Telemetry Applications Optimized for Low Illumination Levels

et al. 2016

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This paper reports the design of a photovoltaic energy harvesting device used as telemetry node in wireless sensor networks. The device draws power from the small solar cell, stores it into the primary energy buffer and backup supercapacitor, collects measured data from various sensors and transmits them over low power radio link at 868 MHz. Its design ensures reliable cold booting under very poor illumination conditions (down to 20 lx). The solar cell also enables indirect illumination level detection for the subcircuit that manages stored energy (day/night detector). The device is allowed to draw power from the backup supercapacitor only when it is not possible to gather enough energy from the solar cell during the sleep period. Short lasting and sudden drops of the illumination do not activate the backup power supply. A wireless sensor node design is adjusted to the proposed photovoltaic harvesting circuitry, so the overall power consumption in the sleep mode is less than 25 µW. Also, due to adaptive power consumption, proposed device topology ensures its autonomy time in the total darkness of 81 h. The device has been produced using commercially available components enabling versatile telemetric functionality by the implementation of different sensors.

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