Nlt Technologies, Ltd.

Setsuko Mio

An LED driving circuit, an LED driving method, and a liquid crystal display device, which prevent deterioration of display quality by effectively shortening the time required for starting the LED backlight and stabilizing the driving operations are provided. The LED driving circuit for controlling an LED circuit constituted with one LED or two or more LEDs includes: a duty ratio adjusting circuit unit which generates/outputs adjusting signals for adjusting drive of the LED based on a PWM dimming signal inputted from outside; and a booster circuit unit which applies driving voltages to the LED circuit according to the adjusting signal outputted from the duty ratio adjusting circuit unit. The duty ratio adjusting circuit unit sets the adjusting signal to have a larger duty ratio than that of the PWM dimming signal within an adjusting period set after the power is supplied until the LED circuit starts to connect electrically.

LED driving circuit, LED driving method, and liquid crystal display device

An example LED backlight driving circuit includes: an LED circuit including a plurality of LED columns that are connected in parallel, each of LED column including one or more LEDs that are connected in series; an LED control circuit connected to constant current circuits corresponding to a parallel number of the LED columns, the LED control circuit including a circuit that controls ON/OFF of a driving current of the LED and a dimming determination circuit that outputs a control signal capable of arbitrarily setting the driving current according to a dimming signal. The LED control circuit performs control based on first driving in which dimming is performed by varying a current value of the driving current of the LED and second driving in which the ON/OFF of the driving current is controlled in addition to the varying of the current value.

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Kanagawa, Japan

Setsuko Mio