Patent ID: 9653142
Date: 2017-05-16
CPC Classifications: G11C,H01L

Claim:
1. A refresh control method of a volatile semiconductor memory device, wherein the volatile semiconductor memory device comprises a plurality of general-memorizing memory cells, the refresh control method of the volatile semiconductor memory device comprising: comparing, by a first comparator, a memory voltage of the general-memorizing memory cell with a first threshold voltage and outputting a first comparison signal; comparing, by a second comparator, the memory voltage of the general-memorizing memory cell with a second threshold voltage and outputting a second comparison signal; comparing, by a third comparator, the memory voltage of the general-memorizing memory cell with a third threshold voltage and outputting a third comparison signal; and generating, by a control signal generator, a control signal according to the first comparison signal, the second comparison signal and the third comparison signal, and outputting the generated control signal to control a switch part of the volatile semiconductor memory device, wherein the control signal has a first logic level when the memory voltage is within a specific threshold range, the control signal has a second logic level when the memory voltage is outside the specific threshold range, and the threshold range is determined according to the first threshold voltage, the second threshold voltage and the third threshold voltage.