Current-generating circuit

Claim 2

In a television receiver having a cathode-ray tube with a deflection yoke and a pair of deflection coil systems, one of which produces a deflection field which deflects an electron beam in a cathode ray tube in one direction, and the other of which produces a deflection field which deflects the electron beam in the cathode-ray tube in a direction orthogonal to said one direction in response to first and second deflection signals respectively, the first and second deflection signals being of first and second frequencies, the deflection yoke further having a correction field-producing system for producing a correction field in response to correction control signals, said correction field being centered substantially at the center of the deflection fields produced by the deflection coil systems, a correction control-signal-producing circuit including in combination: supply means responsive to said first deflection signal for providing a control potential varying in magnitude and polarity in accordance with said first deflection signal; bidirectional current-conducting switch means coupled between said correction-field-producing system and the supply means; and means for operating the switch means in response to said second deflection signal at the frequency of the second deflection signal.

Claim 3

The combination according to claim 1 wherein the frequency of the first deflection signal is substantially lower than the frequency of the second deflection signal; so that the bidirectional switch means is operated in response to the second deflection signal a plurality of times during each cycle of the first deflection signal.

Claim 4

The combination according to claim 2 wherein the first deflection signal is a vertical deflection signal, with the control potential varying from a maximum magnitude at one polarity to a maximum magnitude at another polarity for each cycle of the vertical deflection signal, and wherein the second deflection signal is a horizontal deflection signal having trace and retrace portions, with the switch-operating means causing the bidirectional switch means to be rendered conductive during the trace portions and to be rendered nonconductive during the retrace portions of each cycle of the horizontal deflection signal. 4. The combination according to claim 3 wherein the correction field producing system includes a correction field producing winding on the deflection yoke, the correction winding forming part of a resonant circuit having a resonant frequency such that one-half cycle thereof occurs during the retrace interval of the horizontal deflection signal, with the correction current passed by the bidirectional switch means corresponding to the horizontal deflection signal modulated by the vertical deflection signal, the amplitude and polarity of the correction current being dependent upon the amplitude and polarity of the vertical deflection signal at the time of each cycle of the horizontal deflection signal.

Claim 5

In a deflection system for a cathode-ray tube having a toroid deflection yoke with a pair of deflection coils wound thereon with a winding distribution to produce a uniform deflection field, one of the deflection coils being a horizontal deflection coil for deflecting electron beams in the cathode-ray tube in the horizontal direction and the other deflection coil being a vertical deflection coil for deflecting the beams in the cathode-ray tube in a substantially vertical direction in response to horizontal and vertical deflection signals, respectively, the deflection system further including an additional correction winding on the yoke for producing a correction field centered substantially at the center of the deflection fields produced by the deflection coils, a correction current supply circuit for providing a correction current to the correction winding including in combination: means responsive to the vertical deflection signals for producing an input voltage corresponding to the amplitude and polarity of the vertical deflection signal; bidirectional switch means coupled between the correction winding and the input-voltage-producing means; and means for controlling the operation of the bidirectional switch means in accordance with the horizontal deflection signals, the switch means being rendered conductive during trace intervals of the horizontal deflection signals and being rendered nonconductive during retrace intervals thereof.

Claim 6

In a deflection system for a cathode-ray tube having a toroid deflection yoke with a pair of deflection coils wound thereon with a winding distribution to produce a uniform deflection field, one of the deflection coils being a horizontal deflection coil for deflecting electron beams in the cathode-ray tube in the horizontal direction and the other deflection coil being a vertical deflection coil for deflecting the beams in the cathode-ray tube in a substantially vertical direction in response to horizontal and vertical deflection signals, respectively, the deflection system further including an additional correction winding on the yoke for producing a correction field centered substantially at the center of the deflection fields produced by the deflection coils, a correction current supply circuit for providing a correction current to the correction winding including in combination: means responsive to the vertical deflection signals for producing an input voltage corresponding to the amplitude and polarity of the vertical deflection signal; bidirectional switch means coupled between the correction winding and the input-voltage-producing means; and means for controlling the operation of the bidirectional switch means in accordance with the horizontal deflection signals, the switch means being rendered conductive during trace intervals of the horizontal deflection signals and being rendered nonconductive during retrace intervals thereof.

Claim 7

The combination according to claim 5 wherein the horizontal deflection signal is produced by a circuit including a horizontal output transformer for providing the horizontal deflection signals to the horizontal deflection coil, the system further including first and second bifilar windings on the horizontal transformer and interconnected at one of the ends thereof, and wherein the switch means includes first and second diode means, with the first diode means being connected with the other end of the first bifilar winding and the second diode means being connected with the other end of the second bifilar winding, both diode means being connected with the correction-winding means, the diode means being oppositely poled with respect to the correction-winding means, and the bifilar windings being wound in such a manner as to render both of the diode means conductive simultaneously during the trace intervals of the horizontal deflection signals and to render both of the diode means nonconductive during the retrace intervals of the horizontal deflection signals, the input voltage being applied to the common terminal of the interconnected ends of the first and second bifilar windings.

Claim 8

The combination according to claim 6 further including current-limiting means connected in series with each of the diode means between the respective diode means and the correction winding means for limiting the circulating current through the diode means during the trace intervals of the horizontal deflection signal when the diode means are rendered conductive.

Claim 9

The combination according to claim 7 further including capacitor means connected across each of said current-limiting means.

Claim 10

The combination according to claim 7 further including means for applying a DC bias voltage to the interconnected first ends of the bifilar winDing means.

Claim 11

The combination according to claim 7 further including means for providing a DC bias voltage to the correction-winding means at the connection with the diode means.