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:
Aug. 26, 2008
Filed:
Jun. 10, 2005
Chih-jen Yen, Hsinchu, TW;
Chiu-hung Cheng, Hsinchu, TW;
Chih-Jen Yen, Hsinchu, TW;
Chiu-Hung Cheng, Hsinchu, TW;
Novatek Microelectronics Corp., Hsinchu, TW;
Abstract
A voltage-controlled current source (VCCS) is provided. The VCCS controls an output current according to a controlling voltage. The VCCS includes an operational amplifier (OP-amplifier), a transistor, a resistor and a current mirror. The present invention utilizes the characteristics of the OP-amplifier to compensate for the voltage difference between the gate and the source of the transistor so that the resulting terminal voltage on the resistor is equal to the input control voltage. Therefore, the VCCS of the present invention can reduce the factors including process drift, fluctuation in the DC voltage source or the output current that can affect the terminal voltage difference of the resistor and hence the accuracy of the output current.