Leadtrend Technology Corporation

Au Optronics Corporation

Hung-Ching Lee

Chung-Wei Lin

Ching-Chou Yu

Yueh-Han Li

Chien-Ming Ko

Po-Tang Hsu

Tsung-Chien Wu

Wei-Chi Huang

Dang-Ko Wang

Chih-Wei Lin

Ming-Chang Tsou

Sheng-Kai Hsu

Yao-Tsung Chen

San-Yi Li

Mao-Shih Li

Pai-Feng Liu

Chih-Fu Hsu

Hsien-Te Huang

Chun-Hsin Li

Ruei-Jhih Jheng

Bo-Yi Wu

Tzu-Chen Lin

Yeu-Torng Yau

Tsung-Liang Hung

Hong-Wei Lin

Shih Yi Yang

A power supply has multiple DC power sources converted from an AC power source. The power supply has an isolated converter converting the AC power source into an intermediate DC power source, and non-isolated converters converting the intermediate DC power source into the DC power sources, regulated at target output values respectively. A communication channel connects the isolated converter and one of the non-isolated converters, and transmits a feedback signal in association with the target output values. The isolated converter, in response to the feedback signal, regulates the intermediate DC power source at an intermediate target value related to the target output values.

Power supplies with multiple output ports, and control methods thereof

A secondary-side control method of a flyback power converter includes a primary controller included in the flyback power converter generating a first gate control signal to turn on a power switch at a first predetermined valley of a first voltage after the primary controller enters a start-up mode; and a secondary controller included in the flyback power converter generating a trigger pulse to a synchronous switch at a second predetermined valley of a second voltage to make the primary controller enter a secondary-side control mode from the start-up mode after the secondary controller detects a first coupling voltage corresponding to the first gate control signal on the second voltage.

Flyback power converter and secondary-side control method thereof

A secondary controller applied to a secondary side of a power converter includes a control signal generation circuit and a gate control signal generation circuit. The gate control signal generation circuit generates a gate control signal, and generates an injection signal according to the gate control signal. When a superposition voltage is less than a reference voltage, the control signal generation circuit generates a gate pulse control signal, wherein the gate pulse control signal corresponds to an output voltage of the power converter and the injection signal, the gate control signal generation circuit is further used for generating a gate pulse signal according to the gate pulse control signal, and the gate pulse signal is used for making a primary side of the power converter turned on.

Secondary controller applied to a secondary side of a power converter and operation method thereof

A secondary controller applied to a secondary side of a power converter includes a control signal generation circuit. The control signal generation circuit is coupled to an output terminal of the secondary side of the power converter for detecting an output voltage of the secondary side and enabling a pulse signal to a signal source of the secondary side of the power converter, wherein the signal source enables a turning-on signal according to the pulse signal. The turning-on signal is coupled to a primary-side auxiliary winding of the power converter through a secondary-side auxiliary winding of the power converter to make the primary-side auxiliary winding generate a voltage, and a primary controller of a primary side of the power converter makes the primary side of the power converter be turned on according to the voltage.

A secondary controller applied to a secondary side of a power converter includes a control signal generation circuit, a voltage detection signal generation circuit, and a gate control signal generation circuit. The control signal generation circuit generates a short-circuited control signal to a short winding switch after a gate control signal to make the short winding switch be turned on. When an output voltage of the power converter is less than a predetermined voltage, the voltage detection signal generation circuit generates a first detection signal to the control signal generation circuit. The control signal generation circuit further generates a gate pulse control signal according to the first detection signal. The gate control signal generation circuit generates a gate pulse signal according to the gate pulse control signal, wherein the gate pulse signal is used for making a primary side of the power converter be turned on.

A ripple suppressor includes a constant current generation circuit and a voltage regulation circuit. The constant current generation circuit is coupled to a light-emitting diode chain, wherein the constant current generation circuit is used for generating a detection voltage, and generating a constant current to the light-emitting diode chain. The voltage regulation circuit is coupled to the light-emitting diode chain and the voltage regulation circuit, wherein the voltage regulation circuit makes the constant current generation circuit generate the constant current according to the detection voltage and a compensation value, or makes the constant current generation circuit generate the constant current according to the detection voltage, wherein the compensation value is changed with an average voltage generated by the voltage regulation circuit, and the average voltage corresponds to a voltage of an end of the light-emitting diode chain.

Ripple suppressor

A secondary controller applied to a secondary side of a power converter includes a detector and a standby signal generation circuit. The detector is used for detecting a first signal and a second signal of a universal serial bus device, and a frequency of a synchronization signal corresponding to a primary side of the power converter. The standby signal generation circuit is coupled to the detector for delaying a first predetermined time to generate a standby signal to a primary controller of the primary side of the power converter when the detector fails to detect the first signal and the second signal, and the frequency of the synchronization signal is less than a first predetermined frequency, wherein the primary controller enters a standby mode according to the standby signal.

Standby power control for a flyback USB device using primary side frequency and data port sensing

A circuit with adjustable phase delay and a feedback voltage includes a delay setting unit and a phase delay signal generator. The delay setting unit generates a delay time according to an external resistor. The phase delay signal generator includes a plurality of phase delay units. Each phase delay unit includes an edge trigger subunit and a signal generation subunit. The edge trigger subunit receives an input signal, and generates a positive edge trigger signal and a negative edge trigger signal according to a positive edge and a negative edge of the input signal, respectively. The signal generation subunit generates and outputs a phase delay signal according to the positive edge trigger signal, the negative edge trigger signal, and the delay time. The phase delay signal lags the input signal for the delay time.

Circuit with adjustable phase delay and a feedback voltage and method for adjusting phase delay and a feedback voltage

Short protection control circuits and related control methods are disclosed. A disclosed short protection control circuit is adapted for controlling a short protection mechanism providing short protection to several LED chains. The disclosed short protection control circuit has a detection circuit, a first logic circuit and a timer. Coupled to the LED chains, the detection circuit asserts an indication signal when one of the node voltages of the LED chains is lower than an under-current reference. When the indication signal is enabled, the first logic circuit starts blocking the short protection mechanism. The timer times to provide a result when the short protection mechanism is blocked. When the result indicates that the short protection mechanism has been blocked for at least a predetermined time period, the first logic circuit resumes the short protection mechanism.

Short protection control circuits and related control methods

An exemplary LED driving method is adapted for driving multiple LED strings. Each of the LED strings includes single one LED or multiple LEDs connected in series. In particular, the LED driving method includes steps of: obtaining an initial value of a duty-on period of a driving current in a frequency period to thereby acquire a target accumulative luminosity in the initial value of the duty-on period for each of the LED strings; and prolonging the duty-on period of the driving current in the frequency period and assuring an accumulative luminosity in the prolonged duty-on period to be substantially equal to the target accumulative luminosity for each of the LED strings, when the maximum one of the initial values of the duty-on periods of the driving currents in the frequency period for the LED strings is shorter than the frequency period.

Light emitting diode driving method

A LED driving method includes steps of: providing a first pulse width modulation (PWM) signal for determining a brightness of a LED; obtaining a duty cycle of the first PWM signal; and selectively enabling the LED to work with a PWM dimming mode or a direct current (DC) dimming mode according to a relative relationship between a magnitude of the obtained duty cycle and a preset threshold value. Since the LED is performed with a two stage brightness control by use of mixed dimming mode, the driving efficiency of the LED can be improved.

Light emitting diode driving method and driving circuit

A light-emitting adjustment method and a display device are provided. The display device includes a voltage source, a light-emitting diode array, a pulse width modulator, a current sensor and a light-emitting adjuster. The voltage source provides an operating voltage. The pulse width modulator provides operating pulse signals to multiple light-emitting diodes arranged in column in order. The current sensor senses a plurality of overall current values of the light-emitting diodes at different timings during the light-emitting diodes are sequentially enabled. The light-emitting adjuster computes an operating current value of each of the light-emitting diodes according to the overall current values and performs a compensation operation based on the operating current value to obtain and output a compensation signal.

Light-emitting adjustment method and display device

A light emitting diode driving device and driving method thereof are provided. The light emitting diode driving device includes a duty cycle setup unit, a current setup unit, a control unit, and a light emitting diode driving circuit. The duty cycle setup unit is used for outputting duty cycle setup signal. The current set up unit is used for outputting a current setup signal. The control unit is used for receiving the duty cycle setup signal and the current setup signal, and outputting a current control signal and a duty cycle control signal in response to the duty cycle setup signal and the current setup signal. The light emitting diode driving circuit is used for driving at least one light emitting diode in response to the current control signal and the duty cycle control signal.

Light emitting diode driving device and driving method thereof

A light emitting diode (LED) backlight module, a driving apparatus and a driving method thereof are provided. The driving apparatus is adapted to drive at least one LED of at least one lighting unit within the LED backlight module. The driving apparatus includes a latch unit and a switch unit. The latch unit is used for receiving a control backlight data and latching the control backlight data during a frame period according to a trigger signal, so as to output a control signal. The switch unit is coupled to the latch unit and the LED for receiving the control signal to determine whether the LED emits or not.

Light emitting diode backlight module and driving apparatus and method thereof

A light emitting diode structure and a light emitting diode structure forming method are provided. The light emitting diode structure includes a base, a diode chip, and a package lens. The diode chip is mounted on the base. The package lens covers the diode chip. The surface of the package lens includes a plurality of dot structures. The steps of the method include mounting a light-emitting diode chip on a base, assembling a package lens to cover the light emitting diodes chip, and forming a plurality of dot structures on the surface of the package lens.

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Hsin-Chu, Taiwan

Hung-Ching Lee