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| 20080211471 | Adaptive leading-edge blanking circuit and method for switching mode power converter - In an adaptive leading-edge blanking circuit and method for a switching mode power converter, an inductor current of the converter is sensed and compared with a threshold to decide an end point of a leading-edge blanking time. Circuit and method are further provided for preventing the converter from entering pulse skipping mode, which employs a current trimming circuit in an oscillator for a PWM controller in the converter to reduce a charging current in the oscillator if the output voltage of the converter is excessively high, to thereby reduce the oscillator frequency and in turn lower the switching frequency of a high-side power switch of the converter. | 09-04-2008 |
| 20090051411 | Trimmer circuit and method - A trimmer circuit is so configured that an electronic device will break down to produce a high current to trim a fuse. The electronic device is selectively configured to have a breakdown voltage lower than an applied voltage, for the trigger of its breakdown to be controllable. In an embodiment, the electronic device is switched between two states having two breakdown voltages respectively, and the applied voltage is higher than one of the breakdown voltages and lower than the other one. | 02-26-2009 |
| 20100225249 | LED Driver with Direct AC-DC Conversion and Control, and Method and Integrated Circuit Therefor - The present invention discloses an LED driver with direct AC-DC conversion and control function, and a method and integrated circuit therefor. The LED driver comprises: a primary side circuit receiving rectified AC power, the primary side circuit including at least one power switch; a transformer coupled to the primary side circuit and controlled by the at least one power switch to convert a primary voltage to a secondary voltage which is supplied to an LED circuit; and a secondary side circuit coupled to the transformer, the secondary side circuit directly controlling current flowing through the LED circuit and sending a feedback signal to the primary side circuit to control the at least one power switch thereby. | 09-09-2010 |
| 20110012570 | Synchronous driver circuit and integrated circuit for use therein - The present invention discloses a synchronous driver circuit, comprising: an inductor having one end coupled to an input voltage; a first power transistor having one end coupled to the other end of the inductor and another end supplying an output voltage; a second power transistor having one end coupled to the other end of the inductor and another end coupled to ground; a control circuit for controlling the operation of the first and second power transistors; a gate driver coupled to the control circuit and having an output controlling the gate of the first power transistor; and a bootstrap capacitor having one end coupled to a voltage node and the other end coupled to the other end of the inductor, the voltage across the bootstrap capacitor being provided as the operational voltage of the gate driver. | 01-20-2011 |
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| 20090073827 | AUTOMATIC POWER CONTROL SYSTEM FOR OPTICAL DISC DRIVE AND METHOD THEREOF - An automatic power control system, a down sampling circuit and a down sampling method. The automatic power control system is incorporated in an optical disc drive comprising a laser diode for receiving a control signal to generate a laser beam; and a photodetector for detecting the laser beam to generate an analog input signal. The automatic power control system comprises an analog-to-digital converter, a down sampling circuit, a comparator, and a digital-to-analog converter. The analog-to-digital converter converts the analog input signal to digital data. The down sampling circuit, coupled to the analog-to-digital converter, comprises a down sampler, a counter, and a controller. The down sampler receives a predetermined amount of digital data to generate representation data. The counter, coupled to the down sampler, calculates the amount of digital data, and resets the down sampler when the amount equals or exceeds the predetermined count. The controller, coupled to the counter, disables the counter when the digital data is invalid. The comparator, coupled to the down sampling circuit, compares the representation data with predetermined target data to generate error data. The digital-to-analog converter, coupled to the comparator, converts the error data to analog to generate the control signal. | 03-19-2009 |
| 20090141755 | METHOD FOR CONTROLLING LASER POWER OF AN OPTICAL PICKUP UNIT - A method for controlling laser power of an optical pickup unit (OPU) includes: providing a first relationship between the laser power and a driving parameter, wherein the driving parameter is utilized for driving a laser diode (LD) of the OPU, and the first relationship corresponds to a first temperature; utilizing a temperature-related model to convert the first relationship into a second relationship between the laser power and the driving parameter, wherein the second relationship corresponds to a second temperature; and storing the first relationship for being utilized at the first temperature, and storing the second relationship for being utilized at the second temperature. | 06-04-2009 |
| 20090141759 | METHOD FOR DERIVING PRECISE CONTROL OVER LASER POWER OF AN OPTICAL PICKUP UNIT, AND ASSOCIATED AUTOMATIC POWER CALIBRATION CIRCUIT - A method for deriving precise control over laser power of an optical pickup unit (OPU) includes: providing an analog-to-digital converter (ADC) within an automatic power calibration (APC) circuit to derive a path gain and/or a path offset from the APC circuit; and selectively performing compensation according to the gain and/or the path offset, in order to maintain precision of a relationship between the laser power and a target command utilized for controlling the laser power. An associated APC circuit comprising an ADC and at least one compensation module is further provided. The ADC is utilized for deriving a path gain and/or a path offset from the APC circuit. The compensation module is utilized for selectively performing compensation according to the path gain and/or the path offset, in order to control the laser power by a target command. | 06-04-2009 |
| 20100219908 | DIGITAL TO ANALOG CONVERTING METHOD AND DIGITAL TO ANALOG CONVERTOR UTILIZING THE SAME - A digital to analog converter for converting a digital input signal provided by a host to an analog output signal includes a modulator receiving the digital input signal, modulating the digital input signal, and outputting a modulated signal, and a filtering circuit receiving the modulated signal, low pass filtering the modulated signal, and outputting the analog output signal to an output node. The filtering circuit includes a first switching circuit for adjusting the bandwidth of the filtering circuit according to a bandwidth switching signal. | 09-02-2010 |
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| 20110110205 | Apparatus for Controlling Servo Signal Gains of an Optical Disc Drive and Method of the Same - The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In a second mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals. | 05-12-2011 |
| 20110122747 | Automatic Power Control System for Optical Disc Drive and Method Thereof - An automatic power control system, an automatic power control method, a down sampling circuit and a down sampling method. The automatic power control system is incorporated in an optical disc drive comprising a laser diode for receiving a control signal to generate a laser beam; and a photodetector for detecting the laser beam to generate an analog input signal. The automatic power control system comprises an analog-to-digital converter, a down sampling circuit, a comparator, and a digital-to-analog converter. The analog-to-digital converter converts the analog input signal to digital data. The down sampling circuit, coupled to the analog-to-digital converter, comprises a down sampler, a counter, and a controller. The down sampler receives a predetermined amount of digital data to generate representation data. The counter, coupled to the down sampler, calculates the amount of digital data, and resets the down sampler when the amount equals or exceeds the predetermined count. The controller, coupled to the counter, disables the counter when the digital data is invalid. The comparator, coupled to the down sampling circuit, compares the representation data with predetermined target data to generate error data. The digital-to-analog converter, coupled to the comparator, converts the error data to analog to generate the control signal. | 05-26-2011 |
