APPARATUS FOR PERFORMING A HORIZONTAL FREQUENCY SYNCHRONIZATION OF A PWM SWITCHING FREQUENCY

摘要

PURPOSE: An apparatus for performing a horizontal frequency synchronization of a PWM switching frequency is provided to enhance the quality of the products. CONSTITUTION: A horizontal frequency from a horizontal deflector(100) is provided to an oscillation unit(210). The output signal from the oscillator(210) is provided to a vertical PWM controller(220) wherein the operation of PWM is controlled. A PWM output unit(230) provides a vertical triangle wave deflection current which is provided to a low pass filter(240). The low pass filter(240) performs a low pass filtering operation to provide a low frequency component of vertical triangle wave deflection current. The low frequency component of vertical triangle wave is supplied to a vertical deflection unit(250) wherein the vertical magnitude of the video signal is controlled.