National Cheng-kung University

Other

Precision International Corp.

Unelectra International Corp.

Cheng Kung University

Lightek Electronics Co., Ltd.

Hitech Electronics Co., Ltd.

Tsorng-Juu Liang

Jiann-Fuh Chen

Wei-Ching Tseng

Chien-Yi Chen

Ching-Chau Su

Yi-Hsun Hsieh

Wei-Jing Tseng

Ching-Shun Yi

Shih-Ming Chen

Yi-Chuan Tsai

Chien-Ming Huang

Tsai-Fu Lin

Cheng-Chi Tai

Wan-Yi Horng

Chen-Chi Tai

Kuan-Wen Lee

Hau-Chen Yen

Yi-Yuan Chung

Yi-Chien Shen

Chi-Hung Lin

Kai-Hui Chen

Wen-Yu Huang

Lung-Sheng Yang

A method for estimating an output voltage of an isolated resonant converter is disclosed. The proposed method, wherein the isolated resonant converter includes a transformer having an auxiliary winding and a secondary winding, a first output diode electrically connected to the secondary winding in series and a voltage holder coupled to the auxiliary winding, includes: obtaining the output voltage where v(t) is an output voltage of the voltage holder, Vis a forward voltage drop of the first output diode, Nis a number of turns of the secondary winding and Nis a number of turns of the auxiliary winding.

Methods for estimating output current or output voltage of isolated resonant converter

A flyback converter includes a primary side circuit, a secondary side circuit and a controller. The primary side circuit includes a primary winding and a main switch electrically connected to the primary winding. The secondary side circuit includes a secondary winding and an output diode electrically connected to the secondary winding and having a parasitic electrical parameter. The controller generates a correcting parameter for counteracting an effect on an output voltage of the flyback converter from the parasitic electrical parameter, wherein the parasitic electrical parameter is an equivalent series-connection resistance Rof the output diode and the secondary side circuit, and the correcting parameter is calculated based on the formula wherein ndenotes a turns number of the primary winding, ndenotes a turns number of the secondary winding, and Idenotes an initial current value which is detected when the main switch is conducted.

Flyback converter and controlling method thereof

Battery equalization circuits for series charging/discharging and controlling methods thereof are provided. The provided circuit includes a set of series-connected batteries, a switching converter and a magnetic element coupled balance circuit including a magnetic element coupled to the switching converter, wherein the magnetic element takes a branch current from the switching converter to the series-connected batteries so as to cause the set of series-connected batteries to reach a balance.

Battery equalization circuits for series charging/discharging and controlling methods thereof

An AC/DC converter is disclosed. The proposed AC/DC converter generates an output voltage and includes a current ripple eliminator having an input terminal, an energy storage capacitor and an output terminal, wherein the input terminal has an input voltage, the output terminal generates a pure AC component of a voltage feedback signal based on the output voltage, when the input voltage is larger than a first reference voltage, the energy storage capacitor stores a difference between the input voltage and the first reference voltage as an electric energy, otherwise, the energy storage capacitor releases the electric energy to the input voltage, and an operational amplifier operating the AC component and a second reference voltage to determine when the storage capacitor should store or release the electric energy to minimize a ripple of an output power thereof.

Electrolytic capacitor-less AC/DC converter and controlling method thereof

Configurations for an LED driver are disclosed. The proposed LED driver receives an input voltage, drives an LED and includes a compensation capacitor set including a first and a second capacitors connected to each other in series, wherein the first capacitor is electrically connected to the LED, the second capacitor is grounded, the compensation capacitor set provides a compensation voltage to the LED such that the LED is conductible when an instantaneous voltage value of the input voltage is lower than an LED conduction voltage.

LED driver having compensation capacitor set

An LED driver circuit includes: a bridge rectifier, a first compensation capacitor, a second compensation capacitor, and an LED module. The bridge rectifier is connected to an AC input power for producing a rectification output power. The first compensation capacitor is connected to a first rectification output terminal and an AC input terminal of the bridge rectifier. The second compensation capacitor is connected to a second rectification terminal and the AC input terminal of the bridge rectifier. The LED module is connected to the first rectification output terminal and the second rectification output terminal of the bridge rectifier. The first and second compensation capacitors in the present invention can effectively improve the total current harmonic distortion of the LED module and its utilization.

LED driver circuit

An LED driving device includes a rectifier circuit, a first LED module, a first switch, a second LED module, a second switch, and a diode module. The rectifier circuit includes a pair of input terminals and first and second output terminals for receiving an AC voltage and rectifying the AC voltage to output a pulsed rectified voltage. The first LED module and first switch connected in series are electrically connected between the first and second output terminals of the rectifier circuit. The second LED module and second switch connected in series are electrically connected between the first and second output terminals of the rectifier circuit. The diode module is connected between a common node of the first LED module and the first switch and a common node of the second LED module and the second switch.

LED driving device

An LED driving device includes: an LED circuit having an input side for receiving a driving current corresponding to an AC input voltage from an external power source when the magnitude of a driving voltage across the input side is greater than a predetermined value; and a clamp circuit coupled between the input side of the LED circuit and the external power source, and permitting the driving current to pass through for clamping the magnitude of the driving current to a predetermined current level and for clamping the magnitude of the driving voltage to a predetermined voltage level.

Light emitting diode driving device with a simple structure and an enhanced efficiency

An interleaved flyback converter device with leakage energy recycling includes: two flyback converters and an input power. Each flyback converter includes a capacitor, a switch, two diodes, and a transformer. The input power is connected to the capacitors of the two flyback converters respectively. By using the capacitors as input voltage, the two flyback converters are provided with lower voltage rating. The diodes are used to recycle leakage energy directly, and to clamp voltage on power components. Therefore, in addition to enhancing efficiency via recycling leakage energy, the two flyback converters have lower switching losses due to lower switching voltage.

Interleaved flyback converter device with leakage energy recycling

The present invention relates to a high-voltage transformer coil with acoustic wave guiding function, which comprises a plurality of wound wires, an insulated material for packaging said wound wires to form a coil, a high-voltage connector formed on a side of said coil, and at least one wave guide formed on the other side of said coil to transmit acoustic waves generated due to discharge. The high-voltage coil for transmitting acoustic wave of the present invention is particularly suitable for cast resin transformers.

High-voltage transformer coil with acoustic wave guiding function

A power control circuit includes a power switch unit operable so as to enable and disable supply of an input voltage from an external power source to an LC circuit, a voltage detecting unit for generating a first voltage signal in accordance with an output voltage applied to a load and outputted by the LC circuit, and a current detecting unit for generating a second voltage signal in accordance with a current flowing through the power switch unit. A driver receives a pulse width modulation signal from a comparator in accordance with a comparison result between a summation of the first and second voltage signals and a reference voltage, and outputs a driving signal to a control input unit of the power switch unit so as to control a duty cycle of the power switch unit, thereby controlling rated power supplied to the load to correspond to the reference voltage.

Power control circuit for controlling rated power supplied to a load

The present invention relates to a simple detector for partial discharge with the acoustic emission technique, which provides essentially with an acoustic emission sensor being set on a power equipment. Still, the output of the acoustic emission sensor is connected with a preamplifier and a bandpass filter in turn and the output of the bandpass fitted up with a comparator. The signals of square waves generated by the comparator can be transmitted to a microprocessor as concurrently as a counter in the microprocessor can be used to count up times for partial discharge by seconds; then, the resulted times can be displayed. Consequently, it is convenient to determine whether the power equipment is necessarily maintained by means of counting up times for partial discharge.

Simple partial discharge detector for power equipment using acoustic emission technique

A three-stage electronic ballast for metal halide lamps mainly comprises a step-up converter, a step-down converter and a full-bridge DC-AC converter, wherein the step-down converter operates an inductor in a continuous boundary current mode to achieve reducing power loss and enhancing efficiency. Equipped with a micro processor, the electronic ballast further possesses the function of power regulation. The electronic ballast can be added with various protective functions without complex control circuits and sensing elements, thereby becoming a high-quality and low-cost electronic ballast for metal halide lamps.

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Tainan, Taiwan

Tsorng-Juu Liang