Abstract: A charger system which includes a power adapter, an enhanced USB cable and a linear charger. The power adapter includes a two-way voltage divider. The two-way voltage divider receives a reference voltage through a first end and divides the reference to generate a default voltage level, or additionally receives a current request signal through a second end. The enhanced USB cable is coupled to the power adapter for transmitting the adapter output voltage. The linear charger is coupled to the transmission cable to receive the adapter output voltage. Wherein, the power adapter identifies whether the enhanced USB cable is a compliant cable or not, and identifies whether the charger is a compliant charger or not according to the presence of a current request signal. Wherein, the power adapter folds back the output voltage at a current limit level according to the charger current request signal.

Abstract: A light-emitting diode (LED) lighting driver is provided, which includes a bridge rectifier, multiple LED sections, multiple shunt regulators, a weighted current mirror array, a mean power integrator, and a reference generator. The bridge rectifier provides a rectified sinusoidal voltage. The LED sections are coupled in series and coupled to the rectified sinusoidal voltage. Each shunt regulators regulates a shunt current flowing out from the LED sections according to a current reference value. The weighted current mirror array provides a plurality of copy currents. Each copy currents tracks the conduction time of one shunt regulator and also tracks the instantaneous output power of the LED sections. The mean power integrator provides a mean power value by integrating the copy currents. The reference generator provides the current reference values. Each current reference values is directly proportional to the difference between a mean power reference value and the mean power value.

Abstract: This instant disclosure provides a control method for interleaved multiphase Boost PFC converter. The interleaved multiphase Boost PFC converter has a master phase and a plurality of slave phases, the master phase operates in the critical conduction mode, the master of each slave phase has an inductor and a power switch. The control method comprises, configuring the phase difference between each slave phase and the master phase; setting up each slave phase to operate in the critical conduction mode; monitoring the operating mode of each slave phase is in the continuous conducting mode, the discontinuous conducting mode, or the critical conduction mode when the system is disturbed; and adjusting the power switch on time of the slave phase according to the operating mode of the slave phase so as to make the slave phase return to operate in critical conduction mode.

Abstract: A multiple-level power control system is provided, which includes a power state controller, an electric power device, and a multi-level power driver. The power state controller outputs a phase-notch pattern. The multi-level power driver drives the electric power device at one of a plurality of power levels, decodes the phase-notch pattern as a power step command, and switches from one of the power levels to another one of the power levels according to the power step command.

Abstract: This instant disclosure provides a control method for interleaved multiphase Boost PFC converter. The interleaved multiphase Boost PFC converter has a master phase and a plurality of slave phases, the master phase operates in the critical conduction mode, the master of each slave phase has an inductor and a power switch. The control method comprises, configuring the phase difference between each slave phase and the master phase; setting up each slave phase to operate in the critical conduction mode; monitoring the operating mode of each slave phase is in the continuous conducting mode, the discontinuous conducting mode, or the critical conduction mode when the system is disturbed; and adjusting the power switch on time of the slave phase according to the operating mode of the slave phase so as to make the slave phase return to operate in critical conduction mode.

Abstract: A multiple-level power control system is provided, which includes a power state controller, an electric power device, and a multi-level power driver. The power state controller outputs a phase-notch pattern. The multi-level power driver drives the electric power device at one of a plurality of power levels, decodes the phase-notch pattern as a power step command, and switches from one of the power levels to another one of the power levels according to the power step command.

Abstract: A light-emitting diode (LED) lighting driver is provided, which includes a bridge rectifier, multiple LED sections, multiple shunt regulators, a weighted current mirror array, a mean power integrator, and a reference generator. The bridge rectifier provides a rectified sinusoidal voltage. The LED sections are coupled in series and coupled to the rectified sinusoidal voltage. Each shunt regulators regulates a shunt current flowing out from the LED sections according to a current reference value. The weighted current mirror array provides a plurality of copy currents. Each copy currents tracks the conduction time of one shunt regulator and also tracks the instantaneous output power of the LED sections. The mean power integrator provides a mean power value by integrating the copy currents. The reference generator provides the current reference values. Each current reference values is directly proportional to the difference between a mean power reference value and the mean power value.

Abstract: A dimmable light-emitting diode (LED) lamp and a dimmable LED lighting apparatus thereof are provided. The dimmable LED lamp includes a bridge rectifier, a toggle detector, a sustain voltage supply circuit, a counter, an LED light source, and an LED lighting driver. The bridge rectifier receives a source alternating current (AC) voltage through a wall switch and provides a rectified direct current (DC) voltage. The toggle detector monitors a toggle action of the wall switch. The sustain voltage supply circuit provides a sustain voltage. The counter receives the sustain voltage for operation. Moreover, the counter stores and provides an counting value that changes when the toggle detector detects the toggle action. The LED lighting driver converts the rectified DC voltage to a constant current to drive the LED light source. The LED lighting driver also provides multi-level dimming to the LED light source according to the counting value.

Abstract: A light-emitting diode (LED) driver circuit is provided, which includes a transistor, a current regulator, a release diode, and a voltage clamping device. The transistor is coupled in series with an LED string. The LED string is coupled between the transistor and a bus voltage. The current regulator is coupled to the transistor for regulating the current through the transistor and the LED string to a predetermined current. The release diode has an anode coupled between the LED string and the transistor. The voltage clamping device is coupled to the cathode of the release diode for clamping the voltage level at the cathode of the release diode to a predetermined voltage. The voltage clamping device protects the transistor from breakdown when the transistor is turned off for dimming control.

Abstract: A light-emitting diode (LED) driver circuit is provided, which includes a transistor, a current regulator, a release diode, and a voltage clamping device. The transistor is coupled in series with an LED string. The LED string is coupled between the transistor and a bus voltage. The current regulator is coupled to the transistor for regulating the current through the transistor and the LED string to a predetermined current. The release diode has an anode coupled between the LED string and the transistor. The voltage clamping device is coupled to the cathode of the release diode for clamping the voltage level at the cathode of the release diode to a predetermined voltage. The voltage clamping device protects the transistor from breakdown when the transistor is turned off for dimming control.

Abstract: A dimmable light-emitting diode (LED) lamp and a dimmable LED lighting apparatus thereof are provided. The dimmable LED lamp includes a bridge rectifier, a toggle detector, a sustain voltage supply circuit, a counter, an LED light source, and an LED lighting driver. The bridge rectifier receives a source alternating current (AC) voltage through a wall switch and provides a rectified direct current (DC) voltage. The toggle detector monitors a toggle action of the wall switch. The sustain voltage supply circuit provides a sustain voltage. The counter receives the sustain voltage for operation. Moreover, the counter stores and provides an counting value that changes when the toggle detector detects the toggle action. The LED lighting driver converts the rectified DC voltage to a constant current to drive the LED light source. The LED lighting driver also provides multi-level dimming to the LED light source according to the counting value.

Abstract: A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

Abstract: A synchronous rectifier DC/DC converter is provided. The synchronous rectifier DC/DC converter includes a power transformer, a first diode, a first MOSFET, and a first controller. The power transformer includes a core, a primary winding, a secondary winding, and a sense winding. The primary winding is wrapped around the core and receives an input voltage of the synchronous rectifier DC/DC converter. The secondary winding is wrapped around the core and provides the energy of an output current of the synchronous rectifier DC/DC converter. The sense winding is wrapped around the core and provides a sense signal. The first diode is coupled to the secondary winding for rectifying the output current. The first MOSFET is coupled in parallel with the first diode. The first controller is coupled to the sense winding and the first MOSFET for turning on and turning off the first MOSFET according to the sense signal.

Abstract: A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

Abstract: A circuit and a method for controlling the rotating speed of a brushless direct current (BLDC) motor are provided, whose goal is solving the stall problem encountered by conventional BLDC motors driven by pulse width modulation (PWM). The circuit includes a closed-loop control mechanism for adjusting the duty cycle of the motor current of the BLDC motor, thus controlling the rotating speed of the motor. The closed-loop control is based on the comparison of a signal proportional to the actual rotating speed and another signal proportional to the predetermined target rotating speed.

Abstract: A circuit and a method for controlling the power mode of a class-D amplifier are provided. The power mode control circuit comprises an amplitude detector and a duration detector. The amplitude detector provides an amplitude signal according to the absolute signal level of an input signal. The duration detector provides a shut-down signal to a switching control circuit of a class-D amplifier according to the length of the time period in which the amplitude signal is at a predetermined state, wherein the switching control circuit is turned on or turned off in response to the shut-down signal.

Abstract: A circuit and a method for controlling the rotating speed of a brushless direct current (BLDC) motor are provided, whose goal is solving the stall problem encountered by conventional BLDC motors driven by pulse width modulation (PWM). The circuit includes a closed-loop control mechanism for adjusting the duty cycle of the motor current of the BLDC motor, thus controlling the rotating speed of the motor. The closed-loop control is based on the comparison of a signal proportional to the actual rotating speed and another signal proportional to the predetermined target rotating speed.

Abstract: A double reference wave modulation scheme for filterless power amplifiers is disclosed for reducing EMI and common mode voltages. In the filterless power amplifier, differential outputs for driving load impedance are feedback and corrected based on input audio signals. Reference wave generators generate reference waves. A control logic results pulses in the pair of differential outputs in response to a clock signal or a reference voltage and a cross relationship between the input audio signal and the first and second reference waves. Pulses of one of the differential outputs are not overlapped with pulses of the other of the differential outputs for eliminating common mode noises of the power amplifier.

Abstract: A USB hub with a USB powered speaker is provided. This combinational apparatus comprises a USB hub controller, an amplifier stage and a volume controller. The USB hub controller controls a first USB socket and a second USB socket. The first USB socket connects an upstream USB device providing a voltage source. The second USB socket connects a downstream USB device powered by the voltage source. The amplifier stage is also powered by the same voltage source and drives a speaker according to an audio input signal. The volume controller provides a volume signal to control the gain of the amplifier stage. When the total current output by the voltage source is larger than a predetermined value, the volume signal changes in response to the total current.

Abstract: A circuit and a method for controlling the power mode of a class-D amplifier are provided. The power mode control circuit comprises an amplitude detector and a duration detector. The amplitude detector provides an amplitude signal according to the absolute signal level of an input signal. The duration detector provides a shut-down signal to a switching control circuit of a class-D amplifier according to the length of the time period in which the amplitude signal is at a predetermined state, wherein the switching control circuit is turned on or turned off in response to the shut-down signal.