Koninklijke Philips Corporation N.v.

Nxp B.v.

Cornelis Johannes Adrianus Schetters

Reinhold Elferich

Georg Sauerländer

Thomas Dürbaum

Tijmen Cornelis Van Bodegraven

Johannus Emmanuel Maria Lammers

A power converter, comprising an input circuit having a single diode rectifier (D); and a switcher mode power supply IC (SMPS).

Power converter with a single diode rectifier and a filter

Usually, power supplies are not capable of switching off part of the outputs of a main power supply during stand-by. Due to this, stand-by power supplies are used in addition to operation power supplies. Consistent with an example embodiment, a forward converter is provided, including switches in the rectifier circuit thereof. Due to this, the rectifier circuits may be selectively switched on and off. Advantageously, this may allow that the main outputs of such a forward converter are switched off while on stand-by.

Forward converter

A power supply circuit and a switched-mode power supply with a power supply input circuit are proposed. Known power supply circuits comprise a rectifier supplied with an AC voltage and a first smoothing capacitor. To provide a circuit which is suitable for operation over a wide voltage range, it is proposed that at least a second capacitor be provided which is connected by a switching element to the load terminals so that, when the voltage at the load terminals drops below a voltage threshold, the second capacitor is connected to the load terminals. Further embodiments comprise an apparatus for charging the second capacitor, which is preferably equipped with an apparatus for limiting the voltage at the second capacitor to a charging threshold. By suitable selection of the charging threshold, a capacitor may be used as the second capacitor which, despite a high capacitance value, exhibits a small structural size and low component costs due to the relatively low dielectric strength.

Power supply input switching circuit improved with regard to line faults

DC/DC conversion circuit ( ), includes a transformer ( ) having a primary winding ( ), a secondary winding ( ), and an auxiliary winding ( ); a switching transistor (T), including a series circuit with the primary winding ( ) between first and second direct current input terminals ( ); a start circuit (R , C ) connected to a control electrode of the switching transistor (T) for switching the switching transistor (T) on by powering the direct current input terminals ( ); a control transistor connected to the control electrode of the switching transistor (T) for switching off the switching transistor (T) in dependence on a current flowing through the series circuit during operation. The auxiliary winding ( ) and the control transistor (Q) connect to a voltage control circuit ( ) for setting an output power provided at the secondary winding ( ) of the transformer ( ) during operation by a controlled switching-on of the switching transistor (T) in dependence on the magnitude of a current flowing in the primary winding ( ). The conversion circuit ( ) is arranged such that during operation via the auxiliary winding ( ) a voltage required at the control electrode of the switching transistor (T) for on thereof is built up in a time period which is inversely proportional to the amount of output power provided at the secondary winding ( ).

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Nijmegen, Netherlands

Cornelis Johannes Adrianus Schetters