| 摘要 |
An integrated circuit is provided, which disables writing to a storage devic e on the user side once a current is passed therethrough. The integrated circu it (10C) has a flash memory (46) operating as a storage device to/from which writing/erasure is possible when a read/write enable port (R/W) is in a high level. When a power supply (Vdd) is applied to an external power supply inpu t terminal (24), a fuse (18) having a polysilicon interconnection pattern is blown after a set time period by the output of a step up regulator circuit (16). After the fuse (18) is blown, the input of a buffer (20) is fixed to a low level through a resistor (21), so that the read/write enable port (R/W) of the flash memory (46) as the output of an AND circuit (40) is fixed to a low level and the flash memory (46) becomes a read only memory.
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