Browsing by Author "Yang, Ching-Cheng"

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A CHARGE PUMP WITH MPPT CIRCUIT EMPLOYED IN BATTERYLESS PHOTOVOLTAIC IOT TAGS
(2016)
Men, Guan-Yu
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Cheng, Yuan-Po
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Chao, Paul C. -P.
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Yang, Ching-Cheng
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Pribadi, Eka Fitrah
A dc-dc regulator is proposed to attach to the battery-less solar tag applied in the Internet of Things (IoTs) market. Two main purposes in this design is to maximize the power transfer efficiency and to provide a high voltage supply to the back-end circuit. The overall circuit consists of the cross-coupled charge pump, optimal power point tracking and timing control circuit. It is expected to boost the input voltage from 0.55-0.65V to the output of 1-1.1V at 80-100 mu W condition. Gated PFM circuit is adopted in the optimal power point tracking system to modulate the input frequency of the charge pump to match the inner resistance of the solar cell. This system has been taped-out by TSMC 0.18UM 1P6M process twice and N-fab 0.35UM process once. The experimental results of this chip show that the voltage conversion efficiency (VCE) is 97% and the power conversion efficiency (PCE) is 11.7% at 30 W input power condition. The reason of the low efficiency has been found and improved by enhancing the pumping capacitance. The efficiency of the 3rd tape-out in N-fab has been improved to 81.2% according to the simulation results.
A HIGHLY EFFICIENT AND ADAPTIVE SOLAR-ENERGY HARVESTING CIRCUIT FOR BATTERYLESS IOT DEVICES
(2018-01-01)
Yang, Ching-Cheng
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Chao, Paul C. -P.
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Pandey, Rajeev Kumar
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper a new on-chip 2nd generation solar energy harvesting DC-DC converter has been proposed for a battery less Internet of Things (IoTs) Devices. The propose circuit is design to maximize the transfer efficiency and stability as well as enough high power supply to the back-end loads. Altogether the proposed circuit consists of a cross-coupled charge pump, a maximum power point tracking (MPPT) circuit, a timing control circuit and regulator. The range of input voltage is from 0.5V to 3V. Required boosted output voltage is in the range of 1V to 3.3V. The maximum transfer efficiency is more than 60% and the maximum throughout power is 20011W. A gated clock frequency modulation circuit has been designed and employed in the maximum power point tracking (MPPT) unit to lock the input resistance of the charge pump. In addition, to provide a stable voltage to the load a low dropout (LDO) regulator circuit is used. The experimental results show that the maximum power conversion efficiency (PCE) is 78% at 52 W input power condition.
An 80% Effeciency and Highly Adaptable PV Energy Harvest Circuitry With MPPT for IOT Devices
(2017-01-01)
Cheng, Yuan-Po
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Chao, Paul C. -P.
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Men, Guan-Yu
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Yang, Ching-Cheng
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Wang, Tong-Wen
An on-chip DC-DC converter for energy harvesting is proposed for a new battery-less solar cell tag applied to the Internet of Things (IoTs) devices. The main purpose of this design is to maximize the transfer efficiency and to stably provide a high enough supply voltage to the back-end loads. The overall circuit consists of a cross-coupled charge pump, a maximum power point tracking (MPPT) circuit, a timing control circuit and regulator. The input voltage range is from 0.45V to 3V. The output voltage can be boosted to the required level, in the range of 1V to 3.3V, with more than 60% power conversion efficiency. The throughput power is at least 500 mu W. A gated clock frequency modulation circuit is designed and adopted in the MPPT unit to lock the input resistance of the charge pump. In addition, a low-dropout (LDO) regulator circuit is used to provide a stable voltage to the load. The experimental results of chip show that the maximum power conversion efficiency (PCE) is 80% at 33 mu W input power condition.
An efficient energy harvesting circuit for batteryless IoT devices
(2020-01-01)
Yang, Ching-Cheng
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Pandey, Rajeev
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Tu, Tse-Yi
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Cheng, Yuan-Po
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Chao, Paul C-P
A new energy harvesting circuit for battery-less IoT beacon tags is developed herein to maximize power conversion efficiency as well as high throughput power with a wide input-output range. This design energy harvest (EH) circuit incorporates a charge pump (CP) with shoot-through current suppression, a body selector circuit, a maximum power point tracking circuit (MPPT), a timing control circuit, a hysteresis control circuit and a low dropout regulator. Also in this MPPT circuit is a gated clock tuned in a self-adaptive fashion to match the input impedance of the EH circuit to the output impedance of the photovoltaic (PV) panel, thus achieving successfully maximum power point. The circuit is implemented in an integrated chip in an area of 1.2 mm(2) via the TSMC 0.18 process. Experiments on the chip are conducted and the results show that the input voltage range is allowed from 0.55 to 1.7 V to effectively harvest the solar power from a flexible dye-sensitized solar cell. The achieved peak power conversion efficiency (PCE) is 77% at the input power of 52 mu W. For a wide range of lighting luminance (300-1300 lx,) the achieved average PCE is more than 70%. The achieved wide input-output range and the maximum throughput power of 200 mu W is much larger than others reported, while the 77% of PCE is close to that best power conversion efficiency reported.