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:
Jul. 02, 2019
Filed:
Nov. 22, 2016
National Instruments Corporation, Austin, TX (US);
Pablo E. Limon-Garcia-Viesca, Cedar Park, TX (US);
Christopher G. Regier, Cedar Park, TX (US);
National Instruments Corporation, Austin, TX (US);
Abstract
A source-measure unit (SMU) may be implemented with digital control loops and circuitry to digitally compensate for the impact of input bias current on current measurements. One or more buffers having well-defined characteristics with respect to certain parameters which may affect the current measurements may be used in the output signal path of the SMU where a shunt voltage developed across a current sense element is measured. For example, the buffers may conduct/develop respective input bias currents that change perceptibly and predictably with temperature. By measuring the temperature and adjusting a control voltage—which is used to develop the shunt voltage—according to the temperature measurements, the impact of the input bias current[s] on the current measurement[s] may be reduced to negligible levels and/or may be eliminated. The control voltage may be adjusted by adjusting a voltage feedback value representative of the measured shunt voltage, and/or by adjusting a current setpoint used for generating the control voltage.