| 摘要 |
<p>PURPOSE:To switch an inferior bit only by a tester without using a laser light, by providing a control circuit which controls switching of an inferior bit with an involatile memory device for storing address data and an erasing/writing circuit. CONSTITUTION:An address data of an inferior bit is input to an erasing/writing circuit 15, and written into an EEPROM12. A coincidence detecting circuit 13 detects the coincidence of the data of the inferior bit read at a connecting point between the ROM 12 and a load resistance 11 with the actual data for every data, and outputs to a whole address coincidence detecting circuit 14. The circuit 14 detects the coincidence of all the written data and the actual data, and outputs a signal C. A redundant memory is selected by this signal C, so that a data storing memory is switched to the redundant memory. Accordingly, the inferior bit of the data storing memory can be switched to the redundant memory only by the tester without using a laser light.</p> |
