Abstract: A feedback signal stabilized by a capacitor and related to an output voltage of a power converter is used to acquire the output power information of the power converter, and a control circuit uses a second clock not related to the switching frequency of the power converter to count a duration time of the feedback signal being higher than a threshold. When the duration time is higher than a preset time, an abnormal output power of the power converter is distinguished and the power converter will be turned off. The feedback signal will not vary severely even if the output terminal of the power converter is interfered, and the counted duration time will not be influenced when the switching frequency is changing caused by a load changing.

Abstract: A method for reading/writing a chip in a USB type-C cable comprises converting a read/write command into unstructured vendor defined message (UVDM) that is conforming to a USB power delivery specification. Such UVDM will be delivered to the chip via a type-C configuration channel interface. The chip analyzes the UVDM to acquire the read/write command and reads or modifies the content of a non-volatile memory in the chip according to the read/write command. Due to use of the type-C configuration channel interface, which is inherent in the USB type-C cable, to read/write the chip, it needs no extra interface which otherwise increases costs.

Abstract: A method for reading/writing a chip in a USB type-C cable comprises converting a read/write command into unstructured vendor defined message (UVDM) that is conforming to a USB power delivery specification. Such UVDM will be delivered to the chip via a type-C configuration channel interface. The chip analyzes the UVDM to acquire the read/write command and reads or modifies the content of a non-volatile memory in the chip according to the read/write command. Due to use of the type-C configuration channel interface, which is inherent in the USB type-C cable, to read/write the chip, it needs no extra interface which otherwise increases costs.

Abstract: A linear LED driver comprises a transistor having an input terminal coupled to a LED. When the transistor is turned on, the LED is lighted. The linear LED driver further includes a protection circuit for judging whether an instant high voltage variation occurs or not according to at least one of the voltages of a control terminal and an output terminal of the transistor so as to achieve a protection function.

Abstract: A soft-start switching power converter includes a voltage converting circuit and a soft-start circuit. The voltage converting circuit includes a transformer, and a first switch which includes a first terminal connected to the transformer, a second terminal providing a trigger signal, and a control terminal receiving a control signal, and which is controlled to switch between conduction and nonconduction, such that the transformer generates a feedback voltage. The soft-start circuit receives the trigger signal, generates the control signal according to the trigger signal, and determines whether or not to clamp the control signal at a preset voltage level based on the trigger signal.

Abstract: A control chip of a driving circuit for driving a LED array shares a ground terminal with the LED array so that, without an additional winding, the driving circuit can provide a supply voltage for the control chip, implement a zero-current switching function, and implement an over-voltage protection function. Since no additional windings are needed, the related costs and the size of the driving circuit are decreased.

Abstract: A bleeding circuit and method for an electromagnetic interference filter detect whether or not an AC power source connected to the electromagnetic interference filter is removed, establish a discharge path for discharging a capacitor of the electromagnetic interference filter once the connected AC power source is removed, and cut off the discharge path during the AC power source is in connection to the electromagnetic interference filter for decreasing power consumption of the electromagnetic interference filter.

Abstract: An independent bleeding integrated circuit device is provided to replace the bleeding resistor for an EMI filter capacitor, to establish a discharge path between the two terminals of the EMI filter capacitor when the EMI filter capacitor is disconnected from an AC power source, for discharging the EMI filter capacitor. When the EMI filter capacitor is connected with an AC power source, the discharge path is cut off to avoid power loss.

Abstract: Serially connected low voltage transistors are used to replace a high voltage transistor in a voltage conversion circuit for a driver, or parallel connected sub-transistors are used to establish a high voltage transistor having an effective size dynamically adjusted according to loading of the driver, to reduce switching loss and thereby improve the efficiency of the driver.

Abstract: A level shifter includes an input stage circuit, a latch circuit and a transient speed-up circuit. The input stage circuit receives an input signal. The latch circuit is coupled to the input stage circuit through a first output terminal and a second output terminal, and determining steady-state levels of the first and the second output terminals according to the input signal. The transient speed-up circuit is coupled to the first and the second output terminals. When the transient speed-up circuit determines the first and the second output terminals are at the same logic level, the transient speed-up circuit accelerates the positive edge transition of the first or the second terminals.

Abstract: A control circuit and method for a PWM voltage regulator combine a high frequency feedback technique with a constant on-time or constant off-time topology to improve the transient performance of the PWM voltage regulator. The PWM voltage regulator generates a constant on-time or constant off-time depending on a current for generating a PWM signal, and dynamically adjusts the current according to the droop-voltage at its output during a transient period. Therefore, the PWM voltage regulator boosts its transient response without any threshold for load step detection.

Abstract: A phase/frequency detector module, applicable to a digital phase-locked loop, includes: an edge detector for receiving a reference clock signal and a counting clock signal, where when a positive edge of the counting clock signal occurs, if a positive edge of the reference clock signal has occurred, the edge detector outputs an edge-detected signal, else the edge detector outputs an edge-not-detected signal; a counter coupled to the edge detector, where if receiving the edge-detected signal, the counter outputs a counting result forming a frequency error signal, resets, and loads a count value, and if receiving the edge-not-detected signal, the counter continues to count on the positive edge of the counting clock signal; and a frequency phase converter for performing integration over the counting result, where the integral forms a phase error signal.

Abstract: A method and apparatus for dynamically adjusting a dead time of a BLDC motor during a phase change detect the winding current of the BLDC motor during the dead time, and terminate the dead time when the winding current is detected to be substantially or close to zero. Thus, the method and apparatus can optimize the dead time and switch the BLDC motor between two phases at a zero-current point, without reducing the maximum rotation speed of the BLDC motor.

Abstract: An LED driving device includes: a rectifying circuit for outputting a DC voltage to a string of M LED units; (M?1) first switching circuits each coupled between a corresponding one of first to (M?1)th LED units and ground; and a second switching circuit coupled between an Mth LED unit and ground. When the DC voltage is sufficient to turn on first to kth LED units, where 1?k?M, the kth LED unit is coupled to ground through first and second conductive paths provided by a resistor unit, and a corresponding first switching circuit or the second switching circuit, and each of the first to (k?1)th LED units is coupled to ground through a third conductive path provided by a corresponding first switching circuit and the resistor unit.

Abstract: A parameter setting circuit and method for an integrated circuit apply a pulse current to a pin of the integrated circuit during a programming mode of the integrated circuit, and then extract the difference between the voltage on the pin and the DC component of the voltage on the pin to determine a setting signal for parameter setting to an internal circuit of the integrated circuit. By this way, an input pin, an output pin or an input/output pin of the integrated circuit may be used as the pin implementing the parameter setting function.

Abstract: A flyback converter includes a transformer to convert an input voltage into an output voltage, a control circuit senses a primary current of the transformer to generate a current sense signal, and a sensing circuit is configured to sense a variation of the current sense signal between two time points for extracting the input voltage information therefrom.

Abstract: A hysteretic mode LED driver for providing a driving current for an LED includes a hysteretic comparing circuit and a feedback loop. The hysteretic comparing circuit compares a driving current related sensing signal with a reference signal to control the average value of the driving current. The feedback loop senses the error between the average value of the driving current and a target value to adjust the reference signal or the offset of the hysteretic comparing circuit to adjust the average value of the driving current.

Abstract: A power supply uses a power converter to generate a regulated voltage by referencing to a first DC voltage, a low dropout (LDO) regulator to generate an output voltage from the regulated voltage by referencing to a second DC voltage, and a reference voltage generator to dynamically adjust the first DC voltage according to the input voltage and the control voltage of the output transistor of the LDO regulator. The dropout voltage of the LDO regulator can be minimized to maintain the high efficiency of the power supply at different loading or selected output voltages.

Abstract: A buck-boost power converter switches the switches thereof with a novel sequence and extends the switching periods of the switches to reduce the switching loss and conduction loss when the input voltage thereof approaches the output voltage thereof. The influence of the load current of the power converter on the duty thereof is taken into account to switch the power converter between modes at correct time points, so as to prevent the output voltage from being affected by the mode switching.

Abstract: An LED driver includes a power converter to convert an input voltage to a regulated voltage, a current source to be connected with an LED string in series between the power converter and a bias node, and a switching circuit to apply a bias voltage to the bias node to set the total voltage drop of the LED string and the current source. By controlling the total voltage drop of the LED string and the current source, the LED driver will automatically select a boost mode or a buck mode for operation, thereby improving the efficiency thereof.