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. 25, 2003
Filed:
Aug. 29, 2000
Hwan-Rong Lin, Chang Hua Hsien, TW;
Ta-Yuan Lee, Taipei, TW;
Benq Corporation, Taoyuan, TW;
Abstract
A key-pressing circuit has a control unit, a first charge storage circuit, and a key matrix circuit. The control unit has a controlling port and a detecting port, and the controlling port can be in either a grounded state or a floating state. The first charge storage circuit has a charging port that connects to the detecting port of the control unit. The key matrix circuit has a plurality of resistors and an associated plurality of switches. The resistors are connected together in series, forming a series resistor circuit that has a first end and a second end. One end of each switch connects to an end of its associated resistor. The other end of each switch connects to the controlling port of the control unit. The first end of the series resistor circuit connects to the charging port of the first charge storage circuit. The detecting port detects if the charging port of the first charge storage circuit reaches a predetermined voltage. The control unit measures the time period from when the controlling port is set to a grounded state till the detecting port detects a predetermined voltage, and the control unit determines the corresponding position of the actuated switch according to this time period.