Low current voltage supply circuit for an LCD driver
US6118439A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1998 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | Feb 10, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2330/022
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A voltage supply circuit for an LCD driver employs two voltage dividers. A low current voltage divider includes resistive elements having a high resistance, thus providing a bias voltage with a low current. A high current voltage divider includes resistive elements having low resistances, thus providing a bias voltage with a high current. The high current voltage divider provides bias voltage levels with high current at the beginning of each time phase change. Thus, the liquid crystal display receives a high current when updating the bias voltage levels on the LCD, thereby producing a fast settling time. When the bias voltage levels are held constant, however, only the low current voltage divider provides the bias voltage levels to reduce power consumption. A halt mode prevents the liquid crystal display and driver from consuming any power by disconnecting both voltage dividers from the voltage source when in sleep mode. A voltage drop mode produces a reduction in the bias voltage levels by placing another voltage drop in series with the voltage dividers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.