PURPOSE: To prevent the generation of a beat at a free run high voltage circuit to appear in each period of the horizontal scanning frequency of a horizontal synchronizing signal. ;CONSTITUTION: A signal corresponding to a ripple component contained in the smoothed output of a smoothing circuit for smoothing a high-voltage pulse to be provided on the second-order side of a flyback transformer (FBT) T1 is generated by a ripple signal generating circuit 31, and a signal inverting the signal corresponding to the ripple component is superimposed on the smoothed output by a superimposing circuit composed of transistors Q4, Q5 and Q6 or the like. Besides, the signal corresponding to the ripple component is set at a level corresponding to the change of luminance by a level setting circuit 33 and superimposed on the smoothed output. Thus, since the high-voltage ripple contained in the smoothed output can be canceled and the ripple component contained in the smoothed output corresponding to the luminance change can be canceled as well, the beat at the free run high voltage circuit to appear in each period of the horizontal scanning frequency of the horizontal synchronizing signal can be prevented from being generated.;COPYRIGHT: (C)1996,JPO
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