Patent ID: 7821491

Claim:
A driver for a backlight device having an LED circuit comprising: an amplifier receiving a reference voltage at one input thereof for setting drive current to the LED circuit; a driver transistor coupled to an output of the amplifier and the LED circuit for controlling current flow in the LED circuit; a current detector generating a detection voltage representative of current flow in the LED circuit, the detection voltage coupled to a second input of the amplifier, the amplifier controlling the driver transistor to reduce a difference between the reference voltage and the detection voltage; said amplifier comprises a first input transistor and a second input transistor; and an input exchange circuit that inputs said detection voltage to the gate terminal of one input transistor among said first input transistor and second input transistor, and inputs said reference voltage to the other input transistor; and an exchange controller, which is coupled to said input exchange circuit, controls said input exchange circuit, causes said detection voltage to be input to the input transistor having said reference voltage input to it among said first input transistor and said second input transistor, and causes said reference voltage to be input to the input transistor having said detection voltage input to it.