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:
Jan. 09, 2007
Filed:
Jun. 15, 2005
Gabriele Manganaro, Boxborough, MA (US);
Gabriele Manganaro, Boxborough, MA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A calibration circuit for a current source cell includes a reference current source and a transresistance amplifier forming a feedback loop for calibrating the output current of the current source cell. The reference current source supplies a reference current to a first node switchably connected to the current output node of the current source cell. The transresistance amplifier has an input terminal coupled to the first node and an output terminal switchably connected to a calibration node of the current source cell. With the calibration circuit coupled for calibration, an input current develops at the first node being the difference between the output current of the current source cell and the reference current. The transresistance amplifier receives the input current and generates an output voltage for driving the calibration node. The output voltage has a value operative to nullify the difference between the output current and the reference current.