Patent ID: 6218791
Filing Date: 2001-04-17
Classification: H04N

Abstract:
A deflection circuit for generating a deflection current through a deflection coil of a cathode ray tube, comprising:a series arrangement of a choke and a periodically switched electronic switch, the series arrangement being coupled to receive a power supply voltage;a diode and a flyback capacitor, each being arranged in parallel with said switch, the diode having a polarity so as to be conductive during at least part of a Lo period during which said switch is non-conductive;a series arrangement of the deflection coil and an S-capacitor arranged in parallel with the flyback capacitor; anda deflection correction circuit for generating a correction voltage across the deflection coil, characterized in that the deflection correction circuit comprises a controllable active voltage source arranged in the loop formed by the deflection coil, the S-capacitor, and the flyback capacitor for supplying a modulating voltage, said voltage source comprising a switching element for converting a further power supply voltage into the modulating voltage under control of a control signal determining periodically occurring on and off periods of the switching element, the control signal having a control switching period which is substantially shorter than a deflection switching period of said switch.