Patent ID: 8558824

Claim:
A method of generating a driving voltage, the method comprising: inputting a test gradation voltage to a first input terminal and a second input terminal of a buffer, the buffer further including a chopping terminal, an output terminal, a first type first switch to transfer a gradation voltage to the first input terminal, a first type second switch to connect the second input terminal to the output terminal, a second type first switch to transfer the gradation voltage to the second input terminal, a second type second switch to connect the first input terminal to the output terminal, a test switch to transfer a test gradation voltage to the first input terminal and the second input terminal, and a chopping signal latch to latch the logic level of a test driving voltage output from the output terminal when the test switch is on; latching the logic level of the test driving voltage output from the output terminal of the buffer; setting the buffer to a first type when the logic level of the test driving voltage is high level and setting the buffer to a second type when the logic level of the test driving voltage is low level; and operating the buffer set to the first type or the second type to generate a driving voltage corresponding to the gradation voltage, wherein setting the buffer to a first type comprises setting the test switch, the second type first switch; and the second type second switch to off, setting the first type first switch and the first type second switch to on, inputting the gradation voltage to the first input terminal, and outputting the driving voltage corresponding to the gradation voltage from the output terminal, wherein the first type first switch, the first type second switch, the second type first switch, and the second type second switch are off, the test switch is on, and the chopping signal latch latches the logic level of the test driving voltage in a test operation.