Adjustable voltage converter utilizing a charge pump
US5841648A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1997 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | May 29, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/395
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An adjustable charge pump design employs a variable voltage level means to reduce the charge on the charge pump charging capacitor. The charge pump output is thereby controlled without the use of any secondary pass elements applied to the charge pump output voltage. The variable voltage level means, e.g. a variable resistor, "steals" voltage from the charging capacitor in either an inverting charge pump configuration or a doubling configuration. The voltage converter employing the adjustable charge pump is advantageously applied to providing an adjustable contrast control for an LCD display. Certain intrinsic safety requirements are achievable with the present design thereby making possible a backlit, intrinsically safe LCD display.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.