Abstract: A power switching apparatus (P100) for a switching-mode power supply is provided. The switching apparatus (P100) comprises a power switch (M100), a switching controller (SC100), a voltage converter (Ra100) and a power capacitor (Csc100). The power switch (M100) is configured for connection with a power input device to form a power supply circuit to receive power from a power source. The switching controller (Csc100) is operable to turn on or turn off the power switch (M100). When the power switch (M100) is turned on, power is to flow from the power source into the power input device. When the power switch (M100) is turned off, power is to stop flowing from the power source into the power input device. The voltage converter (Ra100) is configured to receive power from the power source when the power switch (M100) is turned on and to output a regulated voltage.

Abstract: A power supply apparatus comprising a power input portion, a rectifying portion, a power conversion portion, a power output portion and an electrical filter is disclosed. The electrical filter is connected intermediate the rectifying portion and the power output portion for reduction of switching noise generated during power switching operations of the power switching circuitry. With such an arrangement, the electrical filter operates in the DC portion of the apparatus and power loss is significantly reduced while switching noise is suppressed nearer the source compared to conventional arrangement. In addition, switching noises due to stray or parasitic capacitance to the metal casing when the power supply is enclosed in a metallic casing to form a power supply module are also mitigated nearer the source.

Abstract: A power conversion apparatus comprises a first power supply rail, a second power supply rail, a power switching branch, and a circuit arrangement for recycling energies stored in parasitic reactive elements. The parasitic reactive element may be a parasitic inductor in series connection with a power switch of a power switching circuit or a parasitic capacitance across a semiconductor power switch. The circuit arrangement may comprise a clamper branch and/or a circuit arrangement comprising an auxiliary semiconductor switch. The clamper branch is for recycling energy stored in a parasitic inductor. An auxiliary semiconductor switch is connected in parallel with an output diode of a power switching circuit and operable by a control circuit to recycle energy stored on the parasitic capacitor.

Abstract: An apparatus for reducing electromagnetic interference due to common mode current in power converters is disclosed. Common mode current flowing through high parasitic capacitance on the load side typically contributes significantly to the electromagnetic interference. In order to reduce the electromagnetic interference the common mode current is reduced by reducing the voltage driving a current through the high parasitic capacitance. A counter-acting voltage source produces a voltage out of phase with the voltage driving the common mode current. Such a counter-acting voltage is obtained with the aid of a winding coupled to the magnetic component in the power converter or by one or more active components. The counter-acting winding is wound with the secondary and primary windings to share the same magnetic core.

Abstract: An apparatus for reducing electromagnetic interference due to common mode current in power converters is disclosed. Common mode current flowing through high parasitic capacitance on the load side typically contributes significantly to the electromagnetic interference. In order to reduce the electromagnetic interference the common mode current is reduced by reducing the voltage driving a current through the high parasitic capacitance. A counter-acting voltage source produces a voltage out of phase with the voltage driving the common mode current. Such a counter-acting voltage is obtained with the aid of a winding coupled to the magnetic component in the power converter or by one or more active components. The counter-acting winding is wound with the secondary and primary windings to share the same magnetic core.

Abstract: An apparatus for reducing electromagnetic interference due to common mode current in power converters is disclosed. Common mode current flowing through high parasitic capacitance on the load side typically contributes significantly to the electromagnetic interference. In order to reduce the electromagnetic interference the common mode current is reduced by reducing the voltage driving a current through the high parasitic capacitance. A counter-acting voltage source produces a voltage out of phase with the voltage driving the common mode current. Such a counter-acting voltage is obtained with the aid of a winding coupled to the magnetic component in the power converter or by one or more active components. The counter-acting voltage source is connected in series with a capacitance element connected between the input and output sides of the converter-input terminal and output terminal when electrical isolation between the input and the output is desired.

Abstract: An apparatus for reducing electromagnetic interference due to common mode current in power converters is disclosed. Common mode current flowing through high parasitic capacitance on the load side typically contributes significantly to the electromagnetic interference. In order to reduce the electromagnetic interference the common mode current is reduced by reducing the voltage driving a current through the high parasitic capacitance. A counter-acting voltage source produces a voltage out of phase with the voltage driving the common mode current. Such a counter-acting voltage is obtained with the aid of a winding coupled to the magnetic component in the power converter or by one or more active components. The counter-acting voltage source is connected in series with a capacitance element connected between the input and output sides of the converter-input terminal and output terminal when electrical isolation between the input and the output is desired.

Abstract: Typically, in a half-bridge converter A DC blocking capacitor and inductance on the primary side combines with the inductor and capacitor on the secondary side to produce complicated converter dynamic characteristics that make converter stabilization difficult. The disclosed system and methods enable converter stabilization by modulating, as a function of the voltage across the DC blocking capacitor, the feedback output error signal or the ramp signal for the PWM controller of the converter. The modulation removes the effect of the resonant circuit formed by the primary inductance and the DC blocking capacitor in the output voltage regulation loop. Further adjustment of the duty cycle of the power switches enables keeping the output voltage undisturbed by voltage variation across the DC blocking capacitor.