Deflection circuit with damping impedance and current compensation

A picture display apparatus comprising:

• a cathode ray tube with a deflection coil;
• and
• a deflection circuit generating a deflection current through the deflection coil for deflecting an electron beam in the cathode ray tube, the deflection current having a scan period and a flyback period, wherein the deflection circuit comprising:
• a series resistor arranged in series with the deflection coil for generating a feedback voltage related to the deflection current;
• a damping impedance arranged in parallel with the deflection coil;
• a drive circuit having an input terminal coupled to the series resistor for receiving the feedback voltage, the drive circuit being coupled to a conversion resistor for receiving an input waveform, and having an output coupled to the series arrangement of the deflection coil and the series resistor, the drive circuit generating the deflection current in response to a difference between the input waveform and the feedback voltage;
• and
• current generating means for generating a correction current within the flyback period,
• characterized in that the current generating means is coupled to the series resistor and/or the conversion resistor, whereby the correction current is activated during at least a last part of the flyback period to obtain a value of the correction current during said at least last part of the flyback period differing from a value of the correction current during the scan period.

A deflection circuit for generating a deflection current through a deflection coil to deflect an electron beam in a cathode ray tube, the deflection current having a scan period and a flyback period, the deflection circuit comprising:

• a series resistor arranged in series with the deflection coil for generating a feedback voltage related to the deflection current;
• a damping impedance arranged in parallel with the deflection coil;
• a drive circuit having an input terminal coupled to the series resistor for receiving the feedback voltage, the drive circuit further being coupled to a conversion resistor for receiving an input waveform, and having an output coupled to the series arrangement of the deflection coil and the series resistor, the drive circuit generating the deflection current in response to a difference between the input waveform and the feedback voltage;
• and
• current generating means coupled to the series resistor and/or the conversion resistor, said current generating means comprising a semiconductor switch being activated during at least a last part of the flyback period for generating a correction current having a value during said at least last part of the flyback period differing from a value of the correction current during the scan period.