| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for driving backlighting LEDs which implements a high contrast ratio while suppressing a screen flicker.SOLUTION: An LED drive circuit 100 drives a backlighting LED string 10 of a display. A current driver 20 is disposed in series with the LED string 10 to supply the LED string 10 with a driving current Ithat is pulsed with an adjustable magnitude, switching frequency and pulse width or is a direct current. A dimming control section 40 changes the combination of the pulse width and the magnitude while fixing the switching frequency at a predetermined first frequency in a first range of target luminance indicated by a dimming signal PWM higher than a predetermined first threshold, and reduces the switching frequency according to the target luminance while fixing the pulse width and the magnitude in a second range of target luminance lower than the first threshold. |
