Circuit in a television display apparatus for producing a sawtooth deflection current through a line deflection coil

Claim 1

A circuit for producing a sawtooth deflection current having trace and retrace periods through a line deflection coil from a supply voltage source, said circuit comprising a trace capacitor and a retrace capacitor both adapted to be coupled to said coil to form a resonant network therewith, a first diode means coupled in parallel with said network for conducting the deflection current during a first part of the trace period, means for conducting said deflection current during a second part of the trace period including a first series arrangement including a second diode and a controllable switch, said first series arrangement being coupled in parallel with the first diode, the conduction time of the switch being adjustable and a second series arrangement including a winding of a first inductive element and a capacitor coupled in parallel with the first diode, said first inductive element adapted to be coupled to the deflection coil, a winding of a second inductive element direct current coupled between the junction of the second diode and the switch and to a terminal of said voltage supply source, switching means coupled to said second diode for blocking any current in the second diode in the retrace period, and a third diode having a first electrode connected to a point of the first inductive element, and a second electrode direct current connected to said terminal of the voltage supply source through said winding of the second inductive element, the winding sense of said winding of said second inductive element and the direction of conductivity of the third diode being such that current can flow therethrough in the retrace period of the deflection current.