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:
Apr. 03, 2007
Filed:
Jul. 29, 2005
Tzu-chao Lin, Kao-Hsiung, TW;
Yuan-hui Chen, Hsin-Chu, TW;
Hai-thanh Nguyen, Sunnyvale, CA (US);
United Microelectronics Corp., Hsin-Chu, TW;
Abstract
A digital-to-analog converter has a plurality of current cells. Each of the current cells has a level shifter and a current source. The level shifter connects to a first power terminal and a second power terminal to convert a first input signal and a second input signal into a first output signal and a second output signal. The current source has two cascaded MOS transistors connected to the first power terminal in series, a first MOS switch having a gate for receiving the first output signal, and a second MOS switch having a gate for receiving the second output signal. A voltage level of the first power terminal is greater than a voltage level of the second power terminal. When one of the current cells operates, one of the first MOS switch and the second MOS switch of the current source is turned on and operates in a saturation region.