| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit which includes a TFT of one conductivity type and which can provide normal output signal amplitude.SOLUTION: Upon the input of the H level to CK1, TFTs 101 and 103 are turned on to fix the potential of a signal output portion Out at the L level. Next, upon the input of a pulse to a signal input portion In, it is set at the H level to increase the gate potential of the TFT 102 up to (VDD-VthN), thereby producing a floating state. This turns on the TFT 102. Next, CK1 is set at the L level, so that the TFTs 101 and 103 are turned off. At the same time, CK3 is set at the H level to increase the potential of the signal output portion, and at the same time, the gate potential of the TFT 102 is increased to be greater than or equal to (VDD+VthN) by the operation of a capacitor 104, so that the H level of the signal output portion Out gets equal to the VDD. When SP is set at the Lo level, CK3 is set at the Lo level, and CK1 is set at the H level, the potential of the signal output portion Out comes to be at the L level again. |
