Abstract: A method and apparatus are provided for a switching mode converter to improve the light load efficiency thereof. The converter is thus operated with three modes by monitoring a feedback signal and a supply voltage. When the feedback signal indicates that loading gets light enough, the converter is switched from the first mode to the second mode, and during the second mode some cycles are skipped. If loading is too light, the converter is switched from the second mode to the third mode, and during the third mode more cycles will be skipped.

Abstract: A controller which has functions of remote control, multiple protection and PWM inside. The controller can shut down and latch the converter, when a failure happens (such as under voltage and over voltage of output, and over power protection). But, under-voltage and over-power protection will also happen when Vin is decreased by AC interruption or Vin source is removed. This invention is to provide a method to reset the latch protection by detecting Vin and Vo voltage.

Abstract: An apparatus and method for reducing the die area of a PWM controller include a protection circuit triggered by a fault index signal for counting, and the counting time is provided for a delay time required by fault verification. Therefore, fault detection circuits can be eliminated and the purpose of reducing the die area can be achieved.

Abstract: An apparatus and method for a flyback power converter reduce the standby output voltage of the flyback power converter by switching the reference voltage provided by a shunt regulator of the flyback power converter or the ratio of voltage divider resistors of the shunt regulator, to reduce the standby power consumption by an output feedback circuit of the flyback power converter, the shunt regulator, and the voltage divider resistors, and thereby the power loss of the flyback power converter in standby mode.

Abstract: A secondary circuit of a flyback power converter has a resistor network to monitor the output current of the flyback power converter, so as to generate a voltage to apply to a base of a bipolar junction transistor to thereby provide a collector signal for output feedback. The resistor network has a temperature-dependent resistance to compensate the temperature dependence of the base-emitter voltage imparted to the output current and thereby stable the output current.

Abstract: A display includes a power supply system using a power controller to switch a power switch to control power delivery, and an image scalar receiving a supply voltage and a supply current from the power supply system. An apparatus and method are proposed to determine a control signal in a standby mode by monitoring the supply voltage or the supply current, to wake up or turn off the power controller to reduce the switching times of the power switch in the standby mode, thereby reducing the switching loss of the power switch and the standby power consumption of the display.

Abstract: A charger has two pins for connecting with a battery therebetween, and an apparatus and method are proposed to determine to wake up or turn off the charger according to a voltage or a current detected from the two pins, to reduce the standby power consumption of the charger.

Abstract: An isolated type power supply includes a transformer, and a power switch and a current sense resistor serially connected to a primary coil of the transformer, and a protection apparatus and method monitor a control signal which is used to switch the power switch in normal operation, and trigger a signal to stop the power from switching when the control signal becomes greater than a threshold. This protection apparatus and method can more quickly detect short circuit of the current sense resistor, and prevent the isolated type power supply from overcurrent impact.

Abstract: Disclosed are methods of detection for output short circuit of a flyback power supply, which detect the current sense signal provided by a current sense resistor serially connected to a power switch of the flyback power supply, and thus quickly identify whether or not the flyback power supply suffers output short circuit.

Abstract: A power converter has a transformer including a primary winding connected between a power input and a power switch, the power switch is switched to deliver power from the power input to a power output, an auxiliary winding provides an induced voltage in such a manner that when the power switch is at a first switch state, the induced voltage reflects an input information of the power converter, and when the power switch is at a second switch state, the induced voltage reflects an output information of the power converter. Two detection signals are generated from the input and output information, respectively, to implement multiple functions and protections.

Abstract: A controller which has functions of remote control, multiple protection and PWM inside. The controller can shut down and latch the converter, when a failure happens (such as under voltage and over voltage of output, and over power protection). But, under-voltage and over-power protection will also happen when Vin is decreased by AC interruption or Vin source is removed. This invention is to provide a method to reset the latch protection by detecting Vin and Vo voltage.

Abstract: A frequency jittering circuit modulates a hysteretic band of an oscillator such that the clock generated by the oscillator has a jitter frequency, and thus a switching mode power supply operative on the clock will have a jittering switching frequency.

Abstract: A flyback power converter includes a power switch connected to a primary side of a transformer, and a sensing signal is provided for a control circuit to switch the power switch so as for the transformer to convert an input voltage into an output voltage. The sensing signal is a function of the input voltage, and the control circuit extracts a variation of the sensing signal during a preset time period. The variation of the sensing signal is used to prevent the output ripple and the green mode entry point of the flyback power converter from varying with the input voltage.

Abstract: A method and apparatus for a flyback converter estimate the next value of the current limit for the flyback converter according to a present current limit value to achieve the maximum output power control of the flyback converter. An arithmetic circuit is used to calculate the next current limit value according three parameters, the present current limit value, the value of the current sense signal taken after a first time period counting from the instant when the present duty is triggered, and the variation of the current sense signal during a second time period, thereby narrowing the tolerance of the output power from the flyback converter.

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 control circuit and method are provided for a flyback converter converting an input voltage to an output voltage, to compensate for an entry point of a burst mode of the flyback converter, so that the entry point is not affected by the input voltage, and audible noise resulted from a higher input voltage is reduced without impacting the light load efficiency of the flyback converter.

Abstract: A power converter uses a PWM controller to provide a driver output to modulate the duty of the power converter. A protection apparatus and method compare a current sense input of the PWM controller with a reference voltage to assert a signal representing failure, count the number of cycles where the signal representing failure is asserted, and reset an enable signal to inhibit the driver output if the signal representing failure is asserted in several cycles.

Abstract: A multi-function machine includes an electrode having a passage, a power supply device electrically connected with the two opposite terminals thereof to the electrode and the workpiece to be processed, a feeder for selectively feeding a gas or fluid to the passage of the electrode, a first laser beam and a second laser beam respectively projected through the passage of the electrode onto the workpiece, and a detection control device for receiving the reflective light wave of the second laser beam reflected by the workpiece.

Abstract: A current limit signal having a multi-slope waveform is provided for a power converter that has a power switch switched to convert an input voltage to an output voltage, for output power control more preciously. The current flowing through the power switch has a maximum value being a function of a duty cycle of the power switch when the power converter operates at a constant output power condition. The current limit signal is generated according to the function, and is compared with a sensing signal produced from the current flowing through the power switch, so as to turn off the power switch if the sensing signal is not lower than the current limit signal.

Abstract: A current limit signal having a multi-slope waveform is provided for a power converter that has a power switch switched to convert an input voltage to an output voltage, for output power control more preciously. The current flowing through the power switch has a maximum value being a function of a duty cycle of the power switch when the power converter operates at a constant output power condition. The current limit signal is generated according to the function, and is compared with a sensing signal produced from the current flowing through the power switch, so as to turn off the power switch if the sensing signal is not lower than the current limit signal.