Sawtooth line circuit for a cathode ray tube
View Patent ↗A circuit arrangement is described for generating a sawtooth current in a cathode ray tube deflection coil. The circuit arrangement has a first and a second multiresonant section. The sections are arranged in series. The cathode ray tube deflection coil is part of the first section. The second section has an inductor. Each section provides a trace period in which the sawtooth current is generated in the cathode ray tube deflection coil and a retrace period in which flyback of the sawtooth current is provided. The circuit arrangement further has a current control circuit coupled to the inductor for controlling the course of the sawtooth current.
1. A circuit arrangement ( 1 ) for generating a sawtooth current (Il 1 , Il 2 ) in a cathode ray tube deflection coil (L 1 ), the circuit arrangement ( 1 ) comprising a first (I) and second (II) multiresonant section arranged in series, the cathode ray tube deflection coil (L 1 ) in series with a trace capacitor (Ct) being comprised in the first section (I), and the second section (II) comprising an inductor (L 2 ), each section (I, II) providing a common truce period (Tr) and a common retrace period (Rt) to provide a flyback of said sawtooth current (Il 1 , Il 2 ), and the circuit arrangement ( 1 ) comprising a current control circuit ( 2 ) being directly coupled to the inductor (L 2 ), and being without a second trace capacitor coupled from said inductor (L 2 ) to ground, the current control circuit controlling the course of the sawtooth current (Il 1 , 1 l 2 ).
2. The circuit arrangement ( 1 ) according to claim 1 , wherein the current control circuit is a current switching circuit (S 1 , S 2 ).
3. The circuit arrangement according to claim 2 , wherein the current control circuit is coupled between two supply voltages (Vcc, GND) of the circuit arrangement ( 1 ).
4. The circuit arrangement ( 1 ) according to claim 1 , wherein the current control circuit ( 2 ) is arranged to effect a cathode ray tube east-west correction.
5. The circuit arrangement ( 1 ) according to claim 4 , wherein the cathode ray tube east-west correction is effected by dynamically adjusting a current switching point (P 1 , P 2 ) in time marking a start of the trace period (Tr).
6. The circuit arrangement ( 10 ) according to claim 1 , wherein the inductor (L 2 ) is a coil or gyrator circuit.
7. A display device comprising a cathode ray tube, the display device comprising a circuit arrangement ( 1 ) for generating a sawtooth current (Il 1 , Il 2 ) in a cathode ray tube deflection coil (L 1 ) coupled to a cathode ray tube, the circuit arrangement ( 1 ) comprising a first (I) and a second (II) multiresonant section arranged in series, the cathode ray tube deflection coil (L 1 ) connected in series with a trace capacitor (Cr) being comprised in the first section ( 1 ), and the second section (II) comprising an inductor (L 2 ), each section (I, II) providing a common trace period (Tr) and a common retrace period (Rt) to provide a flyback of said sawtooth current (Il 1 , Il 2 ), and the circuit arrangement ( 1 ) comprising a current control circuit ( 2 ) being directly coupled to the inductor (L 2 ) without another trace capacitor connected between said inductor (L 2 ) and ground, the control circuit controlling the course of the sawtooth current (Il 1 , Il 2 ).
8. A television set comprising a display device according to claim 7 .