Process of making and a DRAM standby charge pump with oscillator having fuse selectable frequencies
US5410510A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1993 |
| Grant date | Apr 25, 1995 |
| Priority date | — |
| Expiry date | Oct 4, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/401
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An oscillator (108) for a standby charge pump (102,104)in a dynamic random access memory part (30) includes a fuse (136). The fuse can be blown after testing the part while selecting redundant memory cells to reduce the frequency of the oscillator and obtain a lower power part. The oscillator (108) also drives the on-chip self-refresh circuits (106) that operate slower in response to the reduced frequency. Selecting redundant circuits also includes eliminating memory cells that pass the pause test, but by only a certain margin. Reducing the frequency of the oscillator driving the self-refresh circuits would otherwise cause failure of the cells that pass the pause test by only the certain margin. The oscillator circuit includes a ring of inverter stages (112) and a fused voltage bias circuit (110) generating one or another set of bias voltages (118,120) to the ring oscillator to alter its frequency of oscillation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.