| 摘要 |
PURPOSE:To accurately detect the characteristic of a shift register by applying a characteristic test on every bit after obtaining an output signal from each bit synchronizing with the cycle of a clock signal. CONSTITUTION:Scanning signals SH1, SH2,... are outputted from either bit circuit synchronizing with the clock signals phi1 and phi2, and make n-channel MOSFET transistors Tr1 and Tr2,... perform switching operations, therefore, the waveform of a detecting signal SH outputted from an OR circuit 4 becomes the waveform in which the scanning signals SH1, SH2,... are inverted and arranged in time series, and no interference between the waveforms neighboring to the detecting signal SH is generated. Here, in case of generating fatal abnormality in the bit circuit, since no signal is transmitted to the circuit behind the bit circuit, the waveforms in the bit circuits behind an abnormal circuit become the ones not including scanning signals, therefore, the position of the abnormal bit circuit can be discriminated. In such a way, it is possible to detect the characteristic of the shift register 2 with high accuracy. |
