| 摘要 |
<p>PURPOSE:To prevent a malfunction of a program circuit when a fuse circuit supposed to be cut is connected with a high resistance and a power supply voltage VCC is slowly rising. CONSTITUTION:A circuit 1 is a delay circuit with a VCC power supply as an input and a contact point D is once charged up to a high level by a P channel MOS transistor 4 when a power supply is turned on. After the elapse of the delaying time of the circuit 1, the transistor 4 is turned off and an inverter circuit 2 outputs a low level. When a fuse is not cut, the contact point D becomes a low level by the circuit 2. When the fuse is cut, the high level is held. When the fuse is connected with a high resistance, the circuit 2 does not make the potential of the contact point D to a low level because of the high resistance fuse regardless of the rising VCC power supply and a malfunction of the program circuit is prevented.</p> |
