| 摘要 |
PURPOSE:To perform refresh operation only when the incoming of data is present with low frequency, by controlling the execution of refresh operation according to the frequency of access. CONSTITUTION:The write-in/readout control circuit 16 accesses the circulation memory 11 as far as the access is present for write-in or readout. In this case, the circuit 16 outputs the access monitor signal of low level to close the AND gate 19. Accordingly, if the frequency of access is more than the specified value, the flag signal outputted with the refresh control circuit 18 every count of a given number for the clock pulse corresponding to the minimum time required for the refresh does not pass through the gate 19 but is ineffective, allowing no refresh. As a result, only when the incoming of data appears with a low frequency, the refresh is made, the random data can sufficiently be followed, and refresh can be made only as required without decreasing the operating speed of memory. |
