Oscillator circuit for EEPROM high voltage generator
US7132902B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 2004 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | Nov 22, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K4/502
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A semiconductor oscillator circuit for an EEPROM high voltage charge pump utilizes a current generating means to charge a first and a second capacitor alternatively. The charging current produced by the current generating means is inversely proportional to the ambient temperature. The charging current is proportional to the supply voltage and consequently, the oscillator frequency output remains constant over a variable voltage supply. Such a constant frequency characteristic makes a low voltage operation possible, but slows down the oscillator frequency as temperature increases. The slowing of oscillator frequency limits the charge pump output voltage and enhances the lifespan of the EEPROM cells.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.