Digital-to-analog converter with gamma compensation and a liquid crystal display device using same
US5724036A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1995 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Sep 5, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/765
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A DAC is disclosed that includes a decoder having output lines corresponding to digits of digital data. The decoder generates an output corresponding to the value of the digital data on the output lines. The DAC further includes a constant current source, and output means connected to the constant current source for providing an output voltage by a flowing current. The DAC also has driver transistors, where each transistor is connected to one of the decoder output lines and to the constant current source. The output means conducts a current from the constant current source when the connected output line is activated. Current limit transistors are each connected to each one of the driver transistors. The decoder output lines are grouped so as to correspond to each of the ranges of a gamma compensation curve. A common reference voltage for each group is applied to a control terminal of the current limiting transistors associated with the output lines in each group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.