| 摘要 |
In a circuit for controlling the current flow through a coil, such as the horizontal deflection coil of a television receiver, a first switching device including, for example, a first switching transistor and a first damper diode is connected in parallel with a first resonant circuit including a first capacitor and a first coil, which is the coil through which the current flow is to be controlled. A second switching device including for example, a second switching transistor and a second damper diode is connected in parallel with a second resonant circuit including a second capacitor and a second coil. First and second charging capacitors are connected in series with the first and second coils, respectively, and the power is supplied to the first and second resonant circuits for example through a third coil. Switching signals of the same frequency, for example, the horizontal frequency of a video signal, are applied to the first and second switching transistors with the phase difference between such signals being controlled to vary the relative voltages across the first and second charging capacitors and hence "to control" the current flowing through the first coil. The phase difference between the switching signals can be varied by a parabolic correcting signal having the vertical frequency of a video signal to cause the current flow through the horizontal deflection coil to correct for the side pin-cushion distortion of the raster of a cathode ray tube. In another embodiment of the invention, the phase difference between the switching signals can be modulated by a sawtooth wave signal having the vertical frequency so that the voltage across the first or second charging capacitor varies in a sawtooth manner at the vertical frequency and so that if a vertical deflection coil is connected across the first or second charging capacitor a sawtooth shaped current flow will take place through it, causing proper vertical deflection. |
