A method for realzing VGA arousing function of
liquid crystal television and a circuit thereof, wherein the method comprises: according to characteristics of VGA terminal nine-pin
voltage changing from low to high when a VGA is output, adopting an
external circuit, generating a low electric level pulse with adjustable pulse width at will, a main
chip I / O can arouse VGA of a
liquid crystal television and a display through detecting the low electric level pulse; the circuit comprises XS1 which is used as a VGA interface, one I / O interface which uses Detect as the main IC, using VCC as a power source; when a VGA
signal is output, 9 pin A point electric level nine-pin A point electrical level of the VGA termial is changed from low (0V) to high (5V), a low electric level pulse is formed through the circuit B point, once the low electric level pulse is detected by the I / O interface Detect, the VGA function of the
system is aroused. The detecting pin Detect does not occupy a new I / O interface of the main
chip through multiplexed key input port key; the method does not need the main
chip reading registers and detecting VGA line-field synchronously, does not need ADC power supply, which uses characteristics of VGA terminal nine-pin
voltage changing from low to high when a VGA is output to realize VGA arousing function of
liquid crystal televisions and display products.