Switched-capacitor boost converter design and modeling for indoor optical energy harvesting with integrated photodiodes

Abstract

Abstract-Integrated photovoltaic energy harvesting from indoor lighting is appropriate for ultra-low duty cycle applications. Indoor illumination may flicker due to AC mains rectification or pulse-width-modulated dimming, causing ripple on the output voltage. Switched-capacitor DC/DC conversion can increase harvester output voltage and reduce this ripple. We present a switched-capacitor boost converter design, a model that matches measured output voltage within 10% for 500 Hz to 5 MHz switching frequencies, and compare the converter to a series photodiode configuration. The distortion caused by supply ripple on a passive filter delta-sigma modulator is modeled and verified with measurements from a 180nm test chip.

Pespectives of TFET devices in ultra-low power charge pumps for thermo-electric energy sources

“…The interest in power supply circuits able to harvest energy from the surrounding environment for powering embedded systems has been increasing over the last years [1][2][3][4]. Some applications placed in areas of difficult access or severe environmental locations can benefit from the energy harvesting (EH) field, where the constant replacement of batteries is undesired, e.g.…”

“…the biomedical implants or the remote forestall fire sensors. However, some energy harvesting sources such as micro-photovoltaic cells (PV) [1,2] and thermo-electric generators (TEG) [3,4] are characterized by extremely low output voltage and power values, thus preventing their immediate usage. This way, power converters are often required to produce acceptable voltage values to supply the electronic circuit.…”

Novel charge pump converter with Tunnel FET devices for ultra-low power energy harvesting sources

“…The interest in power supply circuits that are able to harvest energy from the surrounding environment for powering portable and wearable low-power systems has been increasing over the last years [1][2][3][4]. Energy harvesting (EH) sources such as microphotovoltaic cells (PV) [1][2] and thermo-electric generators (TEG) [3][4] are characterized by extremely low output voltage and power values, thus preventing their immediate usage.…”

“…Energy harvesting (EH) sources such as microphotovoltaic cells (PV) [1][2] and thermo-electric generators (TEG) [3][4] are characterized by extremely low output voltage and power values, thus preventing their immediate usage.…”

“…Charge pump or switched-capacitor converters have been widely considered to boost the output voltage of EH sources in order to meet the minimum supply voltage requirements of electronic systems [2,4]. Besides the inherent switching losses that characterize these converters, the main difficulty in achieving a good power conversion performance at low input voltage (sub-0.25 V) and low power levels (sub-µW) is related to the high conduction losses of conventional transistors applied in the conversion process [5].…”