Patent ID: 6552504
Filing Date: 2003-04-22
Classification: H04N

Abstract:
A video display deflection apparatus comprising:a first retrace capacitor; a second retrace capacitor; a deflection winding coupled to said first and second retrace capacitors to form a resonant circuit, during retrace; a source of a first control signal at a frequency related to a deflection frequency selected from a range of frequencies; a first switching transistor responsive to said first control signal and coupled to said first retrace capacitor for generating a first retrace pulse voltage in said first retrace capacitor; a second switching transistor responsive to a second control signal having a variable phase with respect to said first control signal and coupled to said second retrace capacitor for generating a second retrace pulse voltage in said second retrace capacitor, said first and said second retrace pulse voltages being applied to said deflection winding to produce a deflection current in said deflection winding; and a controllable phase shifter responsive to a feedback signal indicative of an amplitude of said deflection current for varying said phase of said second control signal relative to a phase of said first control signal to vary a retrace capacitor transformation factor in a manner to oppose a tendency of an amplitude of said deflection current to change; and a source of an input control signal indicative of a value of the selected frequency coupled to said controllable phase shifter for providing fine regulation of said deflection current amplitude at each of the selected frequencies.