Circuit arrangement for producing a direct voltage with reduction of harmonic and high-frequency interferences

Abstract

Abstract A description is given of a circuit arrangement for producing at least an output direct voltage (at 18, 19) from an at least significantly sinusoidal input a.c. voltage (at 2, 3) of a first frequency, comprising a first rectifier device (1), to which the input a.c. voltage (at 2, 3) can be applied and from which from a direct voltage output (4, 5) a rectified voltage can be taken, a first inductance (6), a second rectifier device (7) and a first filter capacitor (8), which, interconnected in the above sequence, form a series arrangement arranged in parallel with the direct voltage output (4, 5), a switched-mode power supply (9) having two input terminals (10, 11) arranged parallel to a first filter capacitor (8) and between which there is a series arrangement including a second inductance (12) and a switching device (13), a second frequency can alternately be switched to the conductive and the non-conductive state and from which the output direct voltage(s) (at 18, 19) can be supplied, the junction point (22) between the first inductance (6) and the second rectifier device (7) is linked to the junction point (24) between the second inductance (12) by a control capacitor and the switching device (13), the first inductance (6) and the control capacitor (23) being rated such that a resonant frequency determined thereby exceeds the second frequency and the latter is chosen to be high compared to the first frequency. Thereby, with little design effort and cost for the components both the voltage increase at the switching device and consequently the high-frequency interferences originating therefrom and also the harmonics of the mains current are reduced.

Inventors

• 👤 Manfred Albach

Bibliographic Details