| 摘要 |
PURPOSE: To provide the inexpensive high voltage generation circuit which has a simple circuit constitution and corrects the pincushion distortion of an image due to the variance of the time for the beam to arrive at the image reception face. CONSTITUTION: A parabolic modulation means 18 is connected to the reference voltage input terminal of a high voltage stabilizing circuit 3 and generates and outputs a reference voltage which is parabolically modulated synchronously with the vertical deflection period so as to obtain the high output voltage which is made higher than the reference one, which is the high output voltage for beam scanning of the center of the image reception face, at the time of scanning both of upper and lower end sides of the image reception face so that the time for the beam to arrive at the image reception face at the time of scanning the center is equal to the one at the time of scanning both of upper and lower end sides. The circuit 3 outputs a switch control signal, whose on-pulse width is varied in accordance with the reference voltage, to vary the crest value of a flyback pulse in accordance with the parabolic modulating signal. A fly back transformer 6 boosts the flyback pulse and outputs the parabolic high output voltage synchronized with the vertical deflecting period and makes the time for the beam to arrive at the image reception face throughout uniform, thus correcting the pincushion distortion. |
