POWER SUPPLY CIRCUIT OF DISPLAY DEVICE, AND DISPLAY DEVICE USING THE SAME

PROBLEM TO BE SOLVED: To provide a power supply circuit for enhancing power efficiency even when it is applied to a display panel whose current consumption varies and to provide a display device using the power supply circuit. SOLUTION: The power supply circuit includes: a coil 106 to which the charge of an input voltage is charged; a switch element 105 for controlling charging/discharging of charge to/from the coil 106; a capacitor 108 for stabilizing an output voltage in a coil charging period; a transmitter 101 for generating a clock signal to be a reference of the output voltage; a comparator 103 for comparing the clock signal with the output voltage; a pulse control circuit 104 for generating a control signal of the switch element 105 according to an output signal from the comparator 103; and a frequency control circuit 102 for controlling a frequency of the clock signal generated from the transmitter 101 based on a vertical synchronizing signal and a horizontal synchronizing signal of a display device. The frequency control circuit 102 controls the frequency of the clock signal differently between a first state in which the number of output times of the horizontal synchronizing signal is included between the first number of output times and the second number of output times which are preset and a second state in which the number of output times is not included between the first and second numbers of times. COPYRIGHT: (C)2010,JPO&INPIT