Circuit for controlling a self-refresh period in a semiconductor memory device
US5495452A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 14, 1994 |
| Grant date | Feb 27, 1996 |
| Priority date | — |
| Expiry date | Jul 14, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/406
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A circuit which controls a self-refresh period of a semiconductor memory device includes a pulse generating circuit which outputs a periodic pulse train in response to an external control signal, a frequency-dividing circuit which outputs a plurality of pulse trains having different respective periods by frequency-dividing the pulse train, at least one temperature detector which detects an ambient temperature of the memory device and outputs a temperature detection signal when the ambient temperature exceeds a predetermined threshold level, at least one voltage detecting circuit which detects a power supply voltage applied to the memory device and outputs a voltage detection signal when the power supply voltage reaches a predetermined level, a combination pulse train generating circuit which outputs a plurality of combination pulse trains by variously combining the plurality of pulse trains output by the frequency-dividing circuit, and a pulse selecting circuit which outputs a self-refresh master clock by selecting one of the combination pulse trains in response to the voltage detection signal and the temperature detection signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.