Patent ID: 6831415
Filing Date: 2004-12-14
Classification: H04N

Abstract:
A circuit for controlling horizontal and vertical sizes of a screen of a cathode ray tube (CRT) monitor, the circuit comprising:a horizontal screen size compensation circuit which compares a voltage value of a horizontal screen size correction signal with a voltage value of a horizontal reference voltage to obtain first and second horizontal current signals and, in response to a horizontal control signal, generates a horizontal correction current signal by subtracting a horizontal variable current signal from the first horizontal current signal, and outputs the horizontal correction current signal; an east-west correction signal controller which generates an east-west direct current (DC) correction signal by combining the horizontal correction current signal with an east-west DC gain signal; a vertical screen size compensation circuit which compares a voltage value of a vertical screen size correction signal with a voltage value of a vertical reference voltage to obtain a vertical current signal, generates a vertical correction current signal as a function of the vertical current signal and a vertical control signal, and outputs the vertical correction current signal; and a vertical screen size correction signal controller which compares a sawtooth voltage signal with a sawtooth reference voltage, amplifies a difference between the sawtooth voltage signal and the sawtooth reference signal, converts the amplified signal into a sawtooth current signal, and generates a vertical screen size control signal by subtracting the vertical correction current signal from the sawtooth current signal.