Patent application number | Description | Published |
20080298095 | Light-load efficiency improving method and apparatus for a flyback converter - A flyback converter has a controller to switch a power switch so as to convert an input voltage to an output voltage for a load by monitoring an output voltage dependent signal and a current sensing signal derived from a current flowing through the power switch, a light-load efficiency improving apparatus monitors the load and a supply voltage provided for the controller to selectively clamp the output voltage dependent signal when the load is lower than a first threshold value and the supply voltage is lower than a second threshold value, so as to increase the supply voltage. | 12-04-2008 |
20090027027 | Anti-ring asynchronous boost converter and anti-ring method for an asynchronous boost converter - The phase node voltage or the PWM signal in an asynchronous boost converter is monitored to detect a phase node voltage ringing. When a phase node voltage ringing is detected, a detection signal is asserted to establish a bypass path to bypass the inductor of the converter. A charge bypass circuit is shunt to the inductor, and controlled by the detection signal to establish the bypass path. Due to the bypass path, the phase node voltage is maintained at a constant, and the phase node voltage radiation and input/output noise are eliminated. | 01-29-2009 |
20090116160 | Arrangement and method for an integrated protection for a power system - For protecting a power system, two or three of over current, thermal and under voltage protection circuits are integrated as one protection circuit but operate independently, and one or more protection points thereof are adjusted dynamically in response to detected condition of the power system. Specifically, using voltage and current conditions in the power system to modify the over current protection and the thermal protection maximizes the performance of the power system and covers the process bias in the circuits. | 05-07-2009 |
20090267695 | Class AB output stage with programmable bias point control - A class AB output stage includes a driver to generate a first drive signal and a second drive signal, and two bias voltage sources to provide two bias voltages to level shift the first and second drive signals, in order to drive a pair of high side and low side transistors, respectively. A control circuit provides a control signal to adjust the first and second bias voltages, so as to shift the bias point of the class AB output stage. The control signal is determined according to the currents in the high side and low side transistors and a programmable parameter. By adjusting the parameter, the bias point deviation can be removed to obtain both low quiescent current and best THD performance. | 10-29-2009 |
20100117617 | Negative lock loop and control method for a flyback voltage converter - A flyback voltage converter includes a transformer having a primary winding and a secondary winding, a switch serially connected to the primary winding for being switched to produce a current in the secondary winding, and a negative lock loop to adjust the peak value of the current in the secondary winding according to a current conduction time during which the current in the secondary winding is higher than a current threshold, such that the peak value of the current in the secondary winding will be in inverse proportion to the time. | 05-13-2010 |
Patent application number | Description | Published |
20080224782 | Frequency jittering control circuit and method for using the same - A frequency jittering control circuit wherein by means of the characteristics of a PLL whose input switches between different frequencies, the output frequency of the PLL swings between the different frequencies to achieve the desired frequency jittering. | 09-18-2008 |
20080284503 | Charge Pump Start up Circuit and Method Thereof - The present invention discloses a charge pump start up circuit comprising: a start up transistor having one end which is electrically connected with a voltage supply source, and another end which is electrically connected to a voltage node; and a charge pump circuit having an input which is electrically connected with the voltage node, and an output which is electrically with the gate of the start up transistor. | 11-20-2008 |
20080298605 | Half-Voltage Headphone Driver Circuit - The present invention discloses a half-voltage headphone driver circuit, comprising: at least one operational amplifier providing an output to a headphone speaker, and a charge pump receiving a supply voltage (VDD), generating a positive half-voltage and a negative half-voltage (VDD/2 and −VDD/2) based on the supply voltage, and supplying the positive half-voltage and negative half-voltage as high and low operation levels to the at least one operational amplifier. | 12-04-2008 |
20090115391 | Load-Dependent Frequency Jittering Circuit and Load-Dependent Frequency Jittering Method - The present invention discloses a load-dependent frequency jittering circuit, comprising: a load condition detection circuit for receiving a switching signal and generating an output according to a load condition; a number generator for receiving the output of the load condition detection circuit and generating a number; a digital to analog converter for converting the output of the number generator to an analog signal; and an oscillator for generating a jittered frequency according to the output of the digital to analog converter. | 05-07-2009 |