| 摘要 |
<p>PURPOSE:To operate the 1st circuit in a mode different from the normal operating mode by providing the 2nd circuit operated when the 2nd potential is applied and a transmission circuit sending a signal to the 1st circuit when the 2nd circuit is operated so as to change a potential fed to the power supply potential point. CONSTITUTION:The 2nd circuit 11 which is operated when the 1st potential is fed to the power supply potential point 9 and operated when the 2nd potential is applied, and the transmission circuit 14 sending a signal to the 1st circuit 10 when the 2nd circuit 11 is operated are provided. In the test mode, the 2nd potential is applied to the power supply potential point 9. Since a voltage between the gate and source of an MOS transistor 12 is higher than the threshold voltage, the TR 12 is conductive. As a result, a node (a) is lowered to a potential zero V of a ground potential point, inverted by an inversion buffer 14 and the 2nd potential of the power supply potential point 9 appears at a node (b). The 2nd potential is inputted to the 1st circuit 10 as a test signal and the 1st circuit is operated in the test mode.</p> |
