초록 ▼

A backlight luminescence control device for use in a portable computer to control a backlight of a liquid crystal display. When an AC adaptor is not connected to the portable computer, the device senses the voltage level of a DC battery and generates an electrical signal that indicates the status of

A backlight luminescence control device for use in a portable computer to control a backlight of a liquid crystal display. When an AC adaptor is not connected to the portable computer, the device senses the voltage level of a DC battery and generates an electrical signal that indicates the status of the battery. From the voltage level of the DC battery, the device ascertains the appropriate luminescence level of a cold-cathode fluorescent backlight lamp (CCFL), automatically controls the brightness of the CCFL through several levels of luminosity, and optimizes the luminescence of the CCFL according to the voltage level available in the DC battery.

대표청구항 ▼

[ What is claimed is:] [1.] A circuit for controlling a backlight of a liquid crystal display of a portable computer, comprising:a controller for determining whether alternating current is available for the backlight of the liquid crystal display, measuring a voltage level of a battey when the alter

[ What is claimed is:] [1.] A circuit for controlling a backlight of a liquid crystal display of a portable computer, comprising:a controller for determining whether alternating current is available for the backlight of the liquid crystal display, measuring a voltage level of a battey when the alterating current is not available for the backlight of the liquid crystal display, determining a lumninescence level from the measured voltage level, and generating a luminescence control signal corresponding to the luminescence level determined for controlling the backlight of the liquid crystal display; anda backlight driver for driving the backlight of the liquid crystal display according to the luminescence control signal, said backlight driver comprising:an adapter sensor for sensing whether an alternating current adaptor is connected to the portable computer to convert an alternating current received from an electrical receptacle into a direct current;a first converter for producing a switching signal upon reception of the direct current when the alternating current adaptor is connected to the portable computer;a second converter for transforming the switching signal from the first converter into an alternating current signal and boosting the alternating current signal to supply to the backlight of the liquid crystal display;a luminescence state sensor for sensing the brightness of the backlight of the liquid crystal display;an automatic transceiver for transmitting said luminescence control signal corresponding to the luminescence level when the battery is in use; anda luminescence state controller for determining the backlight luminescence of the liquid crystal display according to signals from said adaptor sensor, said automatic transceiver and said luminescence state sensor; anda luminescence controller for controlling the backlight luminescence of the liquid crystal display according to said luminescence control signal.