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 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: 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 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: An energy-feedback clamping circuit of a power converter is proposed. The converter includes a transformer coupled to a full-wave rectifier circuit. The clamping circuit includes: two clamping diodes having two anodes coupled to each other at a common-anode terminal and two cathodes coupled to two terminals of a secondary winding of the transformer, a first clamping capacitor having a first terminal coupled to a cathode of a first rectifying diode of the rectifier circuit and a second terminal coupled to the common-anode terminal, a second clamping capacitor having a first terminal coupled to a connecting node of the output filtering inductor and capacitor of the rectifier circuit and a second terminal coupled to the common-anode terminal, and a converter circuit having an input terminal coupled to the second clamping capacitor and an output terminal for offering a power source.

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: In a boost converter, an energy recycle circuit can be normally operated only when the output voltage is larger than the input voltage. In certain cases, such as when the output is in the abnormal operation, the output voltage could be equal to or less than the input voltage so that the current on the inductor of the energy recycle circuit would be increased to damage the switch element of the energy recycle circuit, and then the rectifying diodes of the boost converter would be damaged too. The present invention relates to a simple auxiliary circuit including a controllable voltage source for resetting the inductor of the energy recycle circuit under the abnormal operation so as to protect the boost converter and to improve the safety of the power supply.

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 and having a first end and a second end; a central tap transformer having a central tap end, a first end and a second end, said central tap end being connected to said second end of said filtering inductor; a filtering capacitor a first end of which is connected to said first end of said central tap transformer and a second end of which is connected to a negative end of said direct current power supply; a first switch which is connected in series to said second end of said central tap transformer and connected to said negative end of said direct current power supply; an in-series circuit having a second switch and a second capacitor and coupled to said central tap transformer; a rectifying device coupled to a secondary winding of said central tap transformer; and a magnetron coupled to said rectifying device, wherein, said first capacitor, said second capaci