Title of Invention

Energy Harvesting System for Wearble Device and Internet of Thing

Technology

In the recent years, the trend of Internet of Things (IoT) and wearable devices promote popularity of product like smart clothes, smart factory, medical care, car electronics…etc. All of them require operating for long period of time. However, the power and longevity of embedded battery have become a challenge.Also,the size and weight are dominated by embedded battery. In this patent, power management circuits of energy harvesting system has been proposed, which can coordinate with external natural source or electric power to supply the product and remove the battery to reduce the burden of users. Overall power management system is composed of high effciency retifier, pole zero compensation regulator and temperature curvature compensation reference circuit.

In the high power conversion efficiency rectifier, it is combined by the power device and smoothing capacitor. The function of power device is to conduct power. It is concluded current controller and voltage controller. They can respectively reduce leakage current and the voltage drop between the input and ouput to improve the power conversion efficiency. With the technology in the recitifer above, a low voltage, low loss and high power conversion efficiency rectifier has been achieve.

 In the pole-zero compensation linear regulator, it is combined by error amplifier, stability promoter, power device and feedback network. The error amplifier is to improve the voltage precision. The stability promoter is to increase the stability of linear regulator. The feedback network is to detect the output voltage to feedback for the error amplifier and reduce the quiescent current. With the technology in the linear regulator, a low power consumption, low area and high stability linear regulator has been achieve.

In the temperature curvature compensation reference voltage circuit, it  combines (N-1)-order positive curvature reference voltage circuit and (N-1)-order nagtive curvature reference voltage circuit to achieve low temperature coefficient and implement by low power consumption circuit. With the technology in reference voltage circuit, a low power consumption, low temperature coefficient and low voltage reference voltage circuit has been ahieve.

Benefits

This patent try to solve the problem that the embedded battery in wearable device and internet of things dominate the size, the weight and lifespan of product. In this patent, a power management circuits of energy harvesting system has been proposed to replace embedded battery. The following are the improvement of internal circuits.

1. cross-coupling full wave bridge rectifier suffers from leakage current and voltage drop between input and output,resulting low energy conversion efficiency.This patent improve the power device which decrease the leakage current and voltage drop and increase conversion efficiency.
2. Low-dropout linear regulator need large area in implement and consume great amount of power. In this patent, large-area device are replaced and the circuit is operated in low-current region to reduce the cost and power.
3. Bandgap reference circuit has high temperature coefficient and high power consumption. In this patent, two device which is operated in low-current region has opposite temperature curve are combined to compensate the higher-order term,resulting low temperature coefficient and low power consumption

Possible Applications/ Industry Categories

1. Wearbale devices
2. Smart factory
3. Medical care
4. Car electronics

Contact Information

Technology Transfer and Business Incubation Center, NCKU

Contact person：Yi-Yin, Lin

E-mail：ainlin@mail.ncku.edu.tw