Abstract: A power supply circuit of a liquid crystal display device includes a first positive polarity charge charging unit including a first capacitor connected to positive and negative power terminals through switches to charge a charge, a second positive polarity charge charging unit including a second capacitor connected to the positive power terminal and a ground terminal through switches to charge a charge, a first positive polarity charge loading unit loading the charge supplied through the positive power terminal to a negative polarity terminal, a second positive polarity charge loading unit loading the charge charged in the first capacitor to a negative polarity terminal, a third positive polarity charge loading unit loading the charge charged in the second capacitor, and a positive polarity charge charging/loading control unit outputting charging control signals with a same phase to the switches, and periodically or irregularly changing durations of the charging and loading control signals.

Abstract: In order that a boost converter of an LDI can reduce electromagnetic interference by generating a panel driving voltage through the use of a variable frequency, while achieving a stable boosting operation using the same frequency whenever each frame begins, an oscillator generates an oscillation signal having a frequency, which varies in a predetermined pattern or hops in a random pattern around a center frequency, and generates an oscillation signal having a preset fixed frequency whenever each frame begins.

Abstract: A power supply circuit of a liquid crystal display device includes a first positive polarity charge charging unit including a first capacitor connected to positive and negative power terminals through switches to charge a charge, a second positive polarity charge charging unit including a second capacitor connected to the positive power terminal and a ground terminal through switches to charge a charge, a first positive polarity charge loading unit loading the charge supplied through the positive power terminal to a negative polarity terminal, a second positive polarity charge loading unit loading the charge charged in the first capacitor to a negative polarity terminal, a third positive polarity charge loading unit loading the charge charged in the second capacitor, and a positive polarity charge charging/loading control unit outputting charging control signals with a same phase to the switches, and periodically or irregularly changing durations of the charging and loading control signals.

Abstract: In order that a boost converter of an LDI can reduce electromagnetic interference by generating a panel driving voltage through the use of a variable frequency, while achieving a stable boosting operation using the same frequency whenever each frame begins, an oscillator generates an oscillation signal having a frequency, which varies in a predetermined pattern or hops in a random pattern around a center frequency, and generates an oscillation signal having a preset fixed frequency whenever each frame begins.