Grenergy Opto Inc.

Immense Advance Technology Corporation

Ili Technology Corporation

Electronics Research & Service Organization

King Billion Electronics Co., Ltd.

Holtek Semiconductor Corp.

Chipone Technology (beijing) Co., Ltd.

Topic Semiconductor Corp.

Yen-Hui Wang

Chia-Chieh Hung

Chin-Yen Lin

Chi-Hao Wu

Wei-Chuan Su

Ko-Yen Lee

Ching-Rong Chang

Wei-Chun Hsiao

Der-Chwan Wu

Chia-Chien Hung

Yu-Wen Chang

Yen-Ping Wang

Pei-Yuan Chen

Sau-Gee Chen

Ko-Ming Lin

Chu-Chiao Yu

Her-Y Shih

Pen-Li Chou

Gang-Janp Lin

Chang-Ling Sha

Chi-Jung Wang

Yu-Min Shih

Yuan-An Kao

A method for minimizing LED flicker of an LED driver system, the LED driver system comprising a PFC constant average current converter, a capacitor, an LED module, and a current regulator, the method including: a first step: the current regulator generating a control voltage according to an average of a difference between a reference voltage and a voltage at a second end of the LED module; and a second step: the current regulator determining a regulation value for a current flowing through the LED module according to the control voltage.

Method for minimizing LED flicker of an LED driver system

A PFC LED driver having a flicker control mechanism, including: a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power; a single stage PFC constant average current converter, coupled with the bridge rectifier and used for forcing an input current to track the full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a current ripple reducing unit, in series with an LED module to form a load for the output current to flow through, wherein the current ripple reducing unit has a negative feedback control mechanism for forcing a peak of the output current approach an average value of the output current.

PFC LED driver having a flicker control mechanism

A PFC LED driver capable of reducing flicker, including: a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power a single stage PFC constant average current converter, coupled with the bridge rectifier and used for forcing an input current to track the full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a peak current regulator, in series with an LED module to form a load for the output current to flow through, wherein the peak current regulator is used to regulate a peak of the output current at a second preset value, and the second preset value is higher than the first preset value.

PFC LED driver capable of reducing flicker

A PFC LED driver capable of reducing current ripple, comprising: a current source unit, having a control terminal coupled to a control voltage, which is a ratio of a full-wave rectified line input voltage, a first channel terminal coupled to a power line, and a second channel terminal used to generate an output current according to the control voltage; and at least one LED load unit, being in series with the current source unit, wherein each of the at least one LED load unit comprises: a first load, including a first parallel combination of an LED module and a capacitor, wherein the LED module has at least one light emitting diode; a diode, being in a first series combination with the first load; and a switch, being in a second parallel combination with the second series combination.

PFC LED driver capable of reducing current ripple

A cascoded current regulator, including: a first load circuit, having a first load and a current source unit; and a second load circuit, being cascaded with the first load circuit and having a second load and a current mirror unit, wherein a first current flowing through the first load and a second current flowing through the current source unit are controlled by a control voltage, and a third current flowing through the second load and a fourth current flowing through the current mirror unit are generated according to the second current.

Cascoded current regulator

A high side controller capable of sensing input voltage and output voltage of a power conversion circuit, including: a first switch, having a control end and two channel ends, the control end being coupled to a gate signal, and one of the two channel ends being coupled to a voltage signal, wherein the voltage signal is proportional to a negative version of the input voltage when the gate signal is active; an inverting amplification circuit, having an input end coupled to the other one of the two channel ends, and an output end for providing a first processed voltage; and a first sample and hold circuit, having a control input end coupled to the gate signal, an input end coupled to the first processed voltage, and an output end for providing a first sample voltage.

High side controller capable of sensing input voltage and ouput voltage of a power conversion circuit

A fixed dead time PFC controller, comprising: an amplitude normalization circuit, used to generate a normalized signal according to a full-wave rectified input voltage; a comparator circuit, used to compare the normalized signal with a threshold voltage to generate a select signal, wherein the select signal exhibits a first state when the normalized signal is higher than the threshold voltage, and a second state when the normalized signal is lower than the threshold voltage; and a driving signal selection circuit, having a first input end coupled to a first driving signal, a second input end coupled to a second driving signal, a control end coupled to the select signal, and an output end for outputting a gate driving signal.

Fixed dead time PFC controller

A novel LED driver controller, including: an auto-gain control unit, having an input end coupled to an input voltage signal which is derived from a line voltage, and an output end for providing a normalized signal; a comparator, used to perform voltage comparison on the normalized signal and a current sensing signal to generate a turn-off signal, wherein the turn-off signal will change state from inactive to active when the current sensing signal reaches the normalized signal; and a driving circuit, having a set input end, a reset input end, and an output end, the set input end being coupled to a turn-on signal, the reset input end being coupled to the turn-off signal, the output end being used for providing a gating signal.

LED driver controller

A system corrected programmable integrated circuit is applied to a power supply and includes a comparator unit, a digital output unit and a programming unit. The comparator unit includes an external feedback voltage input end and a reference voltage input end for inputting a feedback voltage and a reference voltage respectively, such that when the feedback voltage equals the reference voltage, the comparator unit transmits a control signal to the digital output unit. When receiving the control signal, the digital output unit stops outputting the reference voltage and the current reference voltage is recorded as a programming voltage for outputting to the programming unit. When receiving the programming voltage, the programming unit programs the programming voltage and transmits the voltage to the reference voltage input end. Accordingly, the present invention automatically detects and compensates a system error to reduce external element, yet still achieving a qualified range of product specification.

System corrected programmable integrated circuit

A low-pin count fan speed control system and a method thereof include primarily an activation unit to drive a fan to operate. When the fan starts completely, the fan slows down to a pre-determined rotation speed through an idle speed regulation unit. After achieving a pre-determined temperature through a temperature transition unit, the fan speed beings to increase from the idle speed. When the fan is operating, the rotation speed is properly increased in proportion to the temperature, using a positive temperature regulation slope unit. Therefore, through this method, the rotation speed will not be decreased by foreign objects when the fan is operating and a computer host can be provided with proper heat dissipation.

Low-pin count fan speed control system and a method thereof

The present invention discloses an open loop LED driving circuit, having a turn-on period and a turn-off period, the circuit comprising: a power stage, used to store a magnetic energy supplied from a voltage source during the turn-on period and deliver the magnetic energy to a set of LEDs during the turn-off period; and a control unit, having a turn-off period control terminal coupled to the voltage source, and a channel of which a first terminal is coupled to the power stage and a second terminal is coupled to a reference ground, wherein the channel is switched on at a time according to the voltage of the voltage source to determine the turn-off period.

Open loop LED driving circuit

The present invention discloses an integrated circuit for system calibration, applicable to a power supply, comprising: a comparison module, having a feedback input end coupled to a feedback signal and a reference input end coupled to an analog reference signal for delivering a status signal; a detection and control module, for generating a reference signal and a calibration value according to the status signal, wherein the calibration value is derived from the reference signal at an instant when the status signal changes state, and the calibration value is stored into a calibration value register; a memory module, for receiving, storing and outputting the calibration value; and a reference signal generator, receiving the calibration value to provide the analog reference signal. The present invention can therefore be used to automatically calibrate a system with fewer external components to provide qualified systems.

Integrated circuit for system calibration

A current-level controlling device for a power supply includes a reception end for receiving a current sense signal, a reference voltage generator for generating a reference voltage, an adaptive reference voltage generator, coupled to the reference voltage generator and the reception end, for adjusting the reference voltage according to variation of peak values of the current sense signal, so as to generate an adaptive reference voltage, a comparator, coupled to the reception end and the adaptive reference voltage generator, for comparing the current sense signal and the adaptive reference voltage, to generate a comparison result, and a control unit, coupled to the comparator, for controlling a switch transistor of the power supply according to the comparison result.

Current-level controlling device for a power supply device and related power supply device

The present invention discloses a control circuit with frequency compensation, which can be applied to an open-loop control system. The control circuit includes an oscillator which is additionally connected to a first comparator including a first input end, a second input end and a first output end. The first input end provides for inputting a sampling current, the second input end provides for inputting a total voltage of a reference voltage and a DC-level voltage, and the first output end outputs a down-conversion signal. When the sampling current is larger than the total voltage, the first comparator will generate the down-conversion signal to the oscillator to reduce a frequency of the oscillator, such that a current of the open-loop control system can be controlled effectively to prevent an electronic element form being burned down.

Control circuit with frequency compensation

This patent discloses an efficient PWM controller for generating a pulse signal in response to a feedback signal, capable of operating in a normal mode or a green mode, comprising: a capacitor for building a saw-tooth signal by current integration, the saw-tooth signal having a ramp-up period and a ramp-down period; a first composite current source for the ramp-up period, detachable into a first constant current source and a first variable current source; and a second composite current source for the ramp-down period, detachable into a second constant current source and a second variable current source; wherein, the first variable current source is attached to the first constant current source and the second variable current source is attached to the second constant current source respectively in the green mode.

Growing community of inventors

Hsinchu, Taiwan

Yen-Hui Wang