Abstract: The method and circuit for controlling a sensorless single-phase BLDCM having a stator with a winding are proposed. The provided controlling circuit includes a power supply circuit, an inverter coupled to the winding and the power supply circuit, a BEMF detecting circuit coupled to the winding and the inverter and measuring a BEMF of the winding, and a controller coupled to the power supply circuit, the inverter and the BEMF detecting circuit and analyzing a status of the BEMF to control the BLDCM accordingly. The provided method is based on the motor winding time-sharing theory, and the controller controls the inverter to make the winding used as a driving element with loading current when the absolute value of the BEMF is relatively large and as a sensing element when the absolute value of the BEMF is relatively small.

Abstract: The proposed method for starting a motor having a stator, a rotor, a winding and an asymmetrical air gap, comprising the steps of: (a) exciting said winding with a current impulse such that said stator generates a magnetic field and going to one of steps (b) and (d); (b) driving said rotor to rotate in a first direction if a polarity of a portion of a specific tooth of said stator close to said air-gap and a polarity of a specific magnetic pole of said rotor corresponding to said tooth are opposite; (c) stopping said current impulse at a specific moment such that said rotor is rotated in a second direction by a cogging torque and going to step (f); (d) driving said rotor to rotate in a first direction if a polarity of a portion of a specific tooth of said stator close to said air-gap and a polarity of a specific magnetic pole of said rotor corresponding to said tooth are the same; (e) stopping said current impulse at said moment such that said rotor is rotated in a second direction by an inertia; and (f) dete

Abstract: An apparatus for preventing a boost converter from an abnormal operation is provided. The boost converter includes a transformer, a full-wave rectifier circuit electrically connected to a secondary winding of the transformer, an output filter inductor, an output filter capacitor, a clamping circuit having two clamping diodes with two anodes electrically connected to each other to form a common-anode terminal, a first clamping capacitor with a first terminal electrically connected to a node joining the filter inductor and the filter capacitor, and a second terminal electrically connected to the common-anode terminal, and an energy recycle circuit, and the apparatus includes a controllable voltage source having a first terminal electrically connected to the node and a second terminal electrically connected to the energy recycle circuit.

Abstract: An LLC series resonant converter and a driving method for the synchronous rectification power switches thereof are provided. The LLC series resonant converter includes a bridge circuit, a resonant network, a transformer, a rectification circuit, and a frequency adjustment controller. The bridge circuit includes at least one pair of power switches. The power switches drive the resonant network. The rectification circuit includes at least one pair of synchronous rectification power switches. The synchronous rectification power switches and the power switches have a mapping relation between them. The frequency adjustment controller provides driving signals to the synchronous rectification power switches in response to the operating frequency of the LLC series resonant converter and the series resonant frequency of the resonant network, to implement synchronous rectification in the LLC series resonant converter.

Abstract: A power supply device and a single photo-coupler control circuit thereof are provided. The power supply device includes a single photo-coupler control circuit, a main converter and an auxiliary converter. The main converter connects to an output load. The auxiliary converter connects in parallel with the main converter. The single photo-coupler control circuit, also connected to the output load, monitors the status of the power supply device and controls the main converter and the auxiliary converter accordingly. The single photo-coupler control circuit only has one photo-coupler. The main converter and the auxiliary converter together provide a first output to the output load when the power supply device works in a normal mode. The main converter is turned off so that only the auxiliary converter provides a second output to the output load when the power supply device works in a standby mode.

Abstract: An input stage circuit of a three-level DC/DC converter is provided. The input stage circuit uses metal-oxide-semiconductor field effect transistors (MOSFETs) to discharge a flying capacitor to maintain the voltage across the flying capacitor at a half of the input voltage. Not only can the input stage circuit solve the high voltage issue across the flying capacitor in the prior art, but the circuit is able to operate normally without increasing power consumption during discharging, thereby avoiding problems of the prior art.

Abstract: The push-pull converter for zero-voltage switching of the switches on the primary side of the transformer to have a relatively lower loss is proposed. Which includes: a transformer having a primary winding with a center tap and a secondary winding, an electrical energy storage device having a first terminal coupled to the center tap of the primary winding and a second terminal coupled to a ground, a first switch having a first terminal coupled to a first terminal of the primary winding and a second terminal coupled to the ground, a second switch having a first terminal coupled to the ground and a second terminal coupled to a second terminal of the primary winding, and a rectifier circuit coupled to the secondary winding for transforming an AC output of the secondary winding to a DC output.

Abstract: An input stage circuit of a three-level DC/DC converter is provided. The input stage circuit uses metal-oxide-semiconductor field effect transistors (MOSFETs) to discharge a flying capacitor to maintain the voltage across the flying capacitor at a half of the input voltage. Not only can the input stage circuit solve the high voltage issue across the flying capacitor in the prior art, but the circuit is able to operate normally without increasing power consumption during discharging, thereby avoiding problems of the prior art.

Abstract: An apparatus for reducing the heat losses caused by the DC Bus capacitor current is proposed. The apparatus includes: a double frequency boost converter circuit having two boost converter circuits coupled in parallel, in which two switches, respectively disposed on the two boost converter circuits, are turned on and off alternately to produce an output current having a frequency twice that of control signals of the two switches, and to offer a DC bus respectively, a full-bridge DC-DC converter coupled to an output terminal of the double frequency boost converter circuit for transforming an output of the DC bus to a DC voltage, and a DC bus capacitor coupled to the double frequency boost converter circuit and the full-bridge DC-DC converter in parallel for balancing two corresponding transient powers of the double frequency boost converter circuit and the full-bridge DC-DC converter respectively.

Abstract: An integrated converter is provided. The integrated converter includes an AC/DC converter electrically connected to a three-phase power supply for converting an alternating current into a first direct current and achieving the object of the power factor correction; and a DC/DC converter electrically connected to the AC/DC converter for converting the first direct current into a second direct current, wherein while the AC power supply is electricity-drop, the controlling switch is turned on by the integrated converter and the integrated converter is switched from an AC/DC working mode to a DC/DC working mode, and while the AC power supply is restored to normal, the controlling switch is turned off by the integrated converter and the integrated converter is switched from said DC/DC working mode to the AC/DC working mode.

Abstract: The proposed architecture includes a Dual Boost PFC circuit for receiving the AC input voltage and generating the DC bus voltage, at least one inverter coupled to the Dual Boost PFC circuit for driving at least one CCFL to offer a backlight of a LCD panel, and a DC/DC converter coupled to the Dual Boost PFC circuit for offering power to the LCD apparatus. Since neither the input bridge rectifier nor the DC/DC converter between the PFC circuit and the backlight inverter is included in the presented architecture, relatively the simpler configuration and the higher conversion efficiency than those of the prior art are achieved.

Abstract: A circuit for controlling a brushless permanent magnet motor is provided. The circuit comprises windings, each of the windings having a first end connected at a common node and each of the windings having a second end connectable directly to supply voltages by switches, the second end connected to an upper supply voltage or connected to a lower supply voltage or disconnected from the supply voltages; blocking circuitry connectable with the second ends, the blocking circuitry producing a blocked voltage; a comparator receiving the blocked voltage on one input and a reference voltage on another input, the comparator result indicating polarity of a back emf voltage in the associated winding; and a latch providing control signals for the circuit, an input of the latch enabled by an enable signal, an output of the latch comprising a back emf voltage detection signal. The blocking circuitry and the comparator are duplicated for each of the windings.

Abstract: A method for starting-up a motor having multiple stator windings and a rotor contains first providing current to two of the windings to excite a predefined phase and allowing one of the windings floating, Then, the back electromotive force (BEMF) induced in the floating winding is monitored. If a zero crossing of BEMF occurs in the floating winding within the maximum startup time, then it commutates to the next phase, which is adjacent to the first initial phase in the predetermined sequence of excitation phases. If no zero crossing of BEMF occurs in the floating winding within the maximum startup time, then it commutates to the next phase, which is functionally shifted by two phase-intervals from the predefined phase.

Abstract: In those conventional arts, a DC/DC converter with secondary clamp circuit has a problem of voltage oscillation, and a DC/DC converter with primary clamp circuit has problems of heat and clamping losses due to larger forward and reverse currents passing the primary clamp circuit. The present invention applies a tapped inductor or a set of coupling inductors to a DC/DC converter with primary clamp circuit for reducing the voltage oscillation, and furthermore to decrease the forward and reverse current passing through the clamp circuit for reducing the clamping losses of the clamp circuit.

Abstract: A cross regulation controller and the methods for controlling a boost converter are proposed. The boost converter includes the first and second switch elements, and the first and second output capacitors. The cross regulation controller includes a first feedback control circuit for processing the second voltage, a sampling of the voltage across the second output capacitor, with a reference voltage to produce a third voltage and to transform the third voltage to generate a first pulse signal to drive the first switch element, and a second feedback control circuit for processing the first voltage, a sampling of the voltage across the first output capacitor, with a reference voltage to produce a fourth voltage and to transform the fourth voltage to generate a second pulse signal to drive the second switch element so as to achieve a balancing status between the first voltage and the second voltage.

Abstract: The power converters employing the provided methods and controllers are proposed. The controller includes: a signal preprocessor for generating a current signal according to a sensed current of the transformer, an integrator electrically connected to the signal preprocessor for integrating the current signal and offering an integrated signal, a synthesizer electrically connected to the integrator for receiving and synthesizing the integrated signal and a slope compensation signal to generate a synthesized signal, an operational amplifier of a control loop for generating an amplified error signal, and a PWM comparator electrically connected to the operational amplifier and the synthesizer for comparing the amplified error signal and the synthesized signal and generating a PWM signal to turn on and off a switch of the transformer accordingly.

Abstract: The provided method and control circuit are employed to alternately control the dual boost PFC circuits. The control circuit for alternately controlling parallel-connected first and second boost circuits of a dual boost PFC circuit to achieve a current-sharing of the first and the second boost circuits includes: a first control circuit having a first current control loop for employing an output voltage of the PFC circuit, a feed-forward voltage, and an input reference voltage to generate a current reference, and sending the current reference to an input terminal of the first current control loop to generate a first PWM signal to drive the first boost circuit, and a second control circuit having a second current control loop for receiving the current reference through an input terminal of the second current control loop to generate a second PWM signal to drive the second boost circuit.

Abstract: The power converters employing the provided methods and controllers are proposed. The controller includes: a signal preprocessor for generating a current signal according to a sensed current of the transformer, an integrator electrically connected to the signal preprocessor for integrating the current signal and offering an integrated signal, a synthesizer electrically connected to the integrator for receiving and synthesizing the integrated signal and a slope compensation signal to generate a synthesized signal, an operational amplifier of a control loop for generating an amplified error signal, and a PWM comparator electrically connected to the operational amplifier and the synthesizer for comparing the amplified error signal and the synthesized signal and generating a PWM signal to turn on and off a switch of the transformer accordingly.

Abstract: This invention provides a magnetron high frequency device which includes: a filtering inductor coupled to a positive end of a direct current power supply; a central tap transformer having a central tap end, a first end and a second end; a filtering capacitor; a first switch which is connected in series to the second end of the central tap transformer and connected to a negative end of the direct current power supply; an in-series circuit having a second switch and a second capacitor and coupled to the central tap transformer; a first capacitor connected in-series with the central tap transformer and connected in parallel with the first switch; a rectifying device coupled to a secondary winding of the central tap transformer; and a magnetron coupled to the rectifying device. The first capacitor, the second capacitor and the central tap transformer forms a resonant circuit.

Abstract: The push-pull converter for zero-voltage switching of the switches on the primary side of the transformer to have a relatively lower loss is proposed. Which includes: a transformer having a primary winding with a center tap and a secondary winding, an electrical energy storage device having a first terminal coupled to the center tap of the primary winding and a second terminal coupled to a ground, a first switch having a first terminal coupled to a first terminal of the primary winding and a second terminal coupled to the ground, a second switch having a first terminal coupled to the ground and a second terminal coupled to a second terminal of the primary winding, and a rectifier circuit coupled to the secondary winding for transforming an AC output of the secondary winding to a DC output.