National Yang Ming Chiao Tung University

Tsinghua University

Acbel Polytech Inc.

Ching-Yao Liu

Wei-Hua Chieng

Edward Yi Chang

Stone Cheng

Shyr-Long Jeng

Chih-Chiang Wu

Kuo-Bin Wang

Li-Chuan Tang

Yueh-Tsung Hsieh

Da-Jeng Yao

Newton Tang

Yi Chang

Yueh-Tsung Shieh

A D-mode GaN transistor synchronous rectifier of the present invention includes a power switching module, a peak detection module, and a gate driver module. The peak detection module stores energy when the negative end of the secondary side winding of the power converter is at a high voltage. The power switching module includes a first switch and a D-mode GaN HEMT as a second switch connected in series. The energy is provided to the module gate of the power switching module through the gate driver module to keep the first switch turned on. The gate driver module conducts the module gate and the module source when the positive end of the secondary side winding is at a low voltage, such that a clamp circuit pulls the gate-source voltage of the second switch below threshold and turns it off. The synchronous rectifier replaces conventional diode rectifier, having lower conduction loss and response ringing.

D-mode GaN transistor synchronous rectifier and power converter having the synchronous rectifier

An inductive resonant wireless charging system includes a resonant wireless charging transmitting device, a wireless charging relay device and an inductive wireless charging receiving device. The resonant wireless charging transmitting device transmits a high-frequency radio frequency wave. The wireless charging relay device receives the high-frequency radio frequency wave using an electromagnetic resonance way, and converts the high-frequency radio frequency wave into a low-frequency radio frequency wave to transmit the low-frequency radio frequency wave. The inductive wireless charging receiving device receives the low-frequency radio frequency wave in a manner of electromagnetic induction.

Inductive resonant wireless charging system, resonant wireless charging transmitting device, wireless charging relay device and inductive wireless charging receiving device

A power module includes: a GaN transistor, an NMOS transistor, a first capacitor, a first diode and a second diode. The NMOS transistor is electrically connected to the GaN transistor. A negative electrode of the first capacitor is electrically connected to an anode of the first diode and a gate of the GaN transistor. A cathode of the second diode is electrically connected to a gate of the NMOS transistor. The power module further includes a power module control terminal electrically connected to an anode of the first capacitor and an anode of the second diode.

Power module

A control method of a minimum power input applicable to a wireless power transfer system including a power transmission unit and at least one power receiving unit is provided. The power transmission unit is electrically connected with a control voltage signal and an input voltage signal and accordingly generates the minimum power input. The power transmission unit transmits the minimum power input wirelessly through a wireless transmission to the at least one power receiving unit for receiving. By adjusting the input voltage signal, the duty ratio and resonant frequency of the control voltage signal, the present invention ensures an optimal power transmission efficiency of the wireless power transmission system. Moreover, parameters of a charge pump reservoir and gate driving circuit can be further designed in view of the trend feedback of its gate drive waveforms so as to optimize the effect of the proposed invention.

Control method of a minimum power input

A voltage-controlled varied frequency pulse width modulator is provided, including a frequency-regulating voltage output device which receives a determining voltage, decides a resonant frequency according to the determining voltage and outputs an oscillation signal having the resonant frequency. A duty-ratio-regulating voltage output device receives the oscillation signal and a reference signal to determine a duty ratio through an inverting closed loop, so as to adjust the oscillation signal to have the duty ratio. By employing the proposed voltage-controlled modulator circuit with tunable frequency and varied pulse width of the present invention, a modulation signal having the determined resonant frequency and duty ratio is obtained. Moreover, the present invention can be further combined with gate drive waveform trend feedback designs to achieve superior power transmission efficiency of a wireless power transmission system to optimize the inventive effect of the present invention.

Voltage-controlled varied frequency pulse width modulator

Growing community of inventors

Hsinchu, Taiwan

Ching-Yao Liu