Control arrangement for interfacing a convertor (4) in a switched mode power supply with a mains power supply (1) comprising a switch (14) for controlling input current to the arrangement from the mains power supply to have the same waveform as the input voltage to the arrangement from the mains supply,...http://www.google.de/patents/US4942509?utm_source=gb-gplus-sharePatent US4942509 - Control arrangement for a switch mode power supply
