The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 26, 2000
Filed:
Apr. 27, 1998
Hideaki Uchida, Sagamihara, JP;
Kouji Ohhashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A power supply applies a power-supply voltage VDD to operate an LCD driver circuit. A booster circuit increases the power-supply voltage VDD, generating an LCD-driving voltage VLDC. When the power-supply voltage VDD is equal to or higher than a predetermined voltage, a power-supply voltage detecting circuit outputs the LCD-driving voltage VLCD to a switch circuit. The switch circuit disconnects the line for applying the voltage VLCD, from the line for applying a reference voltage GND. When the power-supply voltage VDD is lower than the predetermined voltage, the power-supply voltage detecting circuit outputs an indefinite voltage to the switch circuit. In this case, the switch circuit short-circuits the line for applying the voltage VLCD, to the line for applying the reference voltage GND. This prevents undesired phenomena, such as flickering, from occurring on the screen of the liquid crystal display, even if the application of power-supply voltage VDD is interrupted.