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:
Mar. 13, 2001
Filed:
Mar. 25, 1999
Ichiro Akiyama, Saitama, JP;
Satoru Yamanaka, Saitama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A positive polarity D/A converter,and a negative polarity D/A converter,are formed of an IC chip having the same structure and the same breakdown voltage respectively. When a horizontal clock signal CKH is in a non-conformity state, a clock monitoring circuit,contained in the negative polarity D/A converter,selects inputs of switch circuits,such that outputs of the positive polarity D/A converter,and the negative polarity D/A converter,can be set to the same potential as an external input. Accordingly, since an output of a D/A converter,and an output of a common circuit,become a substantially identical potential, application of a DC voltage to a liquid crystal layer can be prevented. Alternatively, the same operation as the above can be achieved by monitoring the horizontal clock signal CKH by using a clock monitoring circuit,of the positive polarity D/A converter,.