Clocked power supply unit with galvanic isolation

A method for converting an input-side alternating or direct voltage into an output-side direct voltage in a clocked manner, utilizing a power supply unit with galvanic isolation, having a first primary circuit, which comprises a series circuit of a primary coil of a transformer and a first switch element for pulse length modulation of a voltage at the primary coil and a first control circuit for controlling the first switch element, and having at least one secondary circuit, which comprises a secondary coil of the transformer and a smoothing capacitor which lies parallel to an output direct voltage of the secondary circuit, the method comprising:

• modulating a pulse length of a voltage at a part of the primary coil via a second primary circuit comprising a series circuit consisting of the part of the primary coil and a second switch element;
• and
• switching, by a voltage evaluation circuit, one of (i) the first switch element and (ii) the second switch element for the next switching cycle depending on the level of the input voltage.

A non-transitory computer program product encoded with a computer program stored in a power supply unit which, when executed by executed by a processor of the power supply unit, causes conversion of an input-side alternating or direct voltage into an output-side direct voltage in a clocked manner, the computer program comprising:

• program for modulating a pulse length of a voltage at a part of a primary coil via a second primary circuit comprising a series circuit consisting of the part of the primary coil and a second switch element;
• and
• program for switching, by a voltage evaluation circuit, one of (i) a first switch element and (ii) the second switch element for the next switching cycle depending on the level of the input voltage.