| 摘要 |
PURPOSE:To improve effectively in operating speed by obtaining either a signal via a delay circuit or a signal not via it depending on the program state of a fuse provided so as to control the operation of the delay circuit based on its conductive state thereby changing the delay characteristic by a program. CONSTITUTION:An output of an inverter 2 and an input of an inverter 3 are connected through a polysilicon fuse 10. On the other hand, a transistor (TR)Q10 is provided between the input of the inverter 3 and ground and a pulse phi1 applied to an inverter 1 is fed to the gate. The TRQ10 prevents floating of the gate potential of a TRQ6 when the fuse 10 is blown. When the fuse 10 is conduc tive, the circuit is operated with a large delay time. On the other hand, the fuse 10 is interrupted by laser beam or the like, since the pulse signal theta1 is not inputted to the inverters 1, 2 but the inverter 3 is operated only by a signal theta1', and a pulse signal theta2 is outputted with a small delay time. |
