LED DRIVE DEVICE, LUMINAIRE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To eliminate output charges remaining behind at shutdown and the erroneous operation of an LED short-circuit detection function in LED drive control.

SOLUTION: An LED drive device A is composed of a DC/DC controller A1, an output current driver A2 and an output discharge circuit A3 which are integrated into one. The DC/DC controller A1 controls an output stage B so that the minimum value of LED terminal voltages VLED1 to VLED4 which are input from an LED backlight C and a predetermined reference voltage Vref will match. The output current driver A2 generates an output current ILED for the LED backlight C, and determines based on an enable signal EN and a shutdown signal SHDN whether or not to generate the output current ILED. The output discharge circuit A3 discharges an output voltage Vout when generation of the output voltage Vout and the output current ILED is halted on the basis of the enable signal EN and the shutdown signal SHDN.

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