National Yang Ming Chiao Tung University

Tsinghua University

Acbel Polytech Inc.

Wei-Hua Chieng

Edward Yi Chang

Shyr-Long Jeng

Stone Cheng

Chih-Chiang Wu

Ching-Yao Liu

Li-Chuan Tang

Kuo-Bin Wang

Chia-Hua Chang

Tsung-Lin Chen

Yueh-Tsung Hsieh

Bin-Han Lue

Che-Wei Chang

Yi Chang

Da-Jeng Yao

Yueh-Chin Lin

Ming-Tsan Peng

Shih-Chien Liu

You-Long Sie

Jwu-Shen Hu

Chien-Hsun Chiang

Shin-Wei Huang

Lu-Che Huang

Newton Tang

Fu-Jen Hsu

Yueh-Tsung Shieh

Ching-Wei Shih

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

The present disclosure provides a fast charging driver. The fast charging driver is configured to charge a battery of an electronic device. The fast charging driver includes a fast charging circuit and a charging controller. The fast charging circuit includes a first depletion-type GaN transistor, a first enhancement-type field effect transistor, a second depletion-type GaN transistor and a second enhancement-type field effect transistor. The charging controller is configured to control the fast charging circuit to operate in a constant current mode or a constant voltage mode according to a battery level of the battery. By utilizing the first depletion-type GaN transistor and the second depletion-type GaN transistor with a characteristic of a relatively low switching loss, the power consumption during charging the battery by the fast charging driver is decreased to improve the charge speed.

Fast charging driver

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

The present invention provides a communication system between electric bikes and communication method thereof. The communication system comprises a plurality of electric bikes. Each of the electric bikes comprises a monitor module and a portable electric device, wherein the portable device further comprises a storing unit and a WiFi module. The monitor module is configured to monitor the status of the electric bike to generate a plurality of monitor information. When a temporary network is formed between the electric bikes, the electric bikes transmit the monitor information each other through the temporary network and each of the electric bikes stores the received monitor information.

Communication system between electric bikes and communication method thereof

The present invention provides a current limit circuit apparatus, coupled with the gate of a GaN transistor. The current limit circuit comprises a diode, a first transistor, a second transistor, a first resistor, a second resistor, a third resistor and a fourth resistor. The source and the drain of the first transistor couple with the diode. The source of the second transistor couples with the gate of the first transistor. The source of the first transistor couples with the first transistor. The source of the second transistor couples with the second resistor. The third resistor couples with the fourth resistor and the gate of the first transistor. The first transistor turned off and the gate current is limited. When the current of the gate of the GaN transistor exceeds the predetermined value, the breakdown voltage is increased by limiting the gate current.

Current limit circuit apparatus

A sun-chasing device is provided, including a base, a first transmitter disposed on the base, a second transmitter, a support, a carrier pivotally connected to the support for carrying a solar module, a first supporting component pivotally connected to the first transmitter and the carrier, and a second supporting component pivotally connected to the second transmitter and the carrier. The sun-chasing device has great rigidity and carrying ability against strong wind, and has great precision and rotation angle, such that a solar plate can precisely aim at sun for long time and thus the efficiency of a solar module is significantly increased.

Sun-chasing device

The present invention provides a high-side driver circuit including a power transistor, the first transistor, the second transistor, the second capacitor, the second diode, a start-up circuit. The start-up circuit is coupled between a resistor and the second capacitor to complete a gate driving circuit. And, the aforementioned resistor can either be the gate resistance of the power transistor or an external resistor. The design of start-up circuit enables the functionality of the bootstrap capacitor of being charged to a designate voltage level. Thus, the depletion-mode transistor can be controlled to turn on/off without a floating voltage source or a negative voltage source.

High-side driver circuit

A method for forming a T-shaped gate is provided. The method includes providing a substrate. Then, a photoresist structure is formed over the substrate. The photoresist structure includes two development rates. Next, a mask with an opening is formed over the photoresist structure to pattern the photoresist structure. An angle exposure is applied to the photoresist structure, and the exposed photoresist structure is developed to form a T-shaped notch. A width of the T-shaped notch is gradually reduced from a top portion thereof to a bottom portion to expose a surface of the substrate. Then, a gate metal is deposited in the T-shaped notch. Thereafter, the patterned photoresist structure is removed to form the T-shaped gate.

Growing community of inventors

Hsinchu, Taiwan

Wei-Hua Chieng