POWER SUPPLY COMPRISING MEANS FOR IMPROVING THE POWER FACTOR

摘要

The power supply comprises first rectifier means (1) which can be connected to an electric mains (7) and which comprise first output terminals (9) for supplying a first pulsating direct voltage. A buffer capacitor (11) is connected parallel to the first output terminals (9) and an inverter (13) is connected to the buffer capacitor via first input terminals (15). The power supply also comprises second rectifier means (19) which can be connected to the mains (7) and which comprise second output terminals (23) for supplying a second pulsating direct voltage, and also a converter (29) with second input terminals (27) which are connected to the second output terminals and output terminals (31) which are connected parallel to the buffer capacitor (11). The converter (29) serves to increase the power factor of the energy drawn from the mains (7) by the power supply and is operative to supply a maximum power which is substantially lower than the maximum power of the first rectifier means (1). The converter (29) is formed by a flyback converter which comprises a transformer (33) with a primary winding (35) and a secondary winding (39). The primary winding (35) is connected in series with a switching element (37) in order to form a primary series circuit whose ends are connected to the second input terminals (27) and the secondary winding (39) is connected in series with a rectifier element (41) in order to form a secondary series circuit whose ends are connected to the second output terminals (31).