Lamp control circuit having a brightness condition controller having 2.sup. n .sup.rd and 4.sup.th current paths
US5818172A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1995 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Oct 30, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/07
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A back light circuit for a liquid crystal display (LCD) includes: an alternating current (AC) adapter, a battery for supplying a direct current (DC) when the alternating current (AC) adapter is not used, an adapter detecting unit for determining whether or not the alternating current (AC) adapter is being used, a direct current/direct current (DC/DC) converter for providing output of a switched signal, a direct current/alternating current (DC/AC) converter for driving a cold cathode fluorescent lamp (CCFL) by increasing an electric potential, a cold cathode fluorescent lamp (CCFL) operated by the direct current/alternating current (DC/AC) converter, an on/off controller for controlling the direct current/direct current (DC/DC) converter, a brightness controller for controlling the brightness of the cold cathode fluorescent lamp (CCFL), a feedback unit for providing feed back signals to the direct current/direct current (DC/DC) converter, a brightness condition detector for determining the brightness condition of the back-light of the liquid crystal display (LCD), a low battery/very low battery (LB/LLB) signal transmitter for generating a signal indicating the residual amount of bat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.