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:
Nov. 08, 2005
Filed:
Mar. 17, 2005
Peter R. Holloway, Andover, MA (US);
Eric D. Blom, Wakefield, MA (US);
Jun Wan, Haverhill, MA (US);
Stuart H. Urie, Milford, NH (US);
Peter R. Holloway, Andover, MA (US);
Eric D. Blom, Wakefield, MA (US);
Jun Wan, Haverhill, MA (US);
Stuart H. Urie, Milford, NH (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A digitizing temperature measurement system for providing a digital temperature measurement includes an excitation source for providing switched excitation currents to two or three temperature sensing elements and an ADC circuit including a charge-balancing modulator and a digital post processing circuit. The system utilizes synchronous AC excitation of the temperature sensing elements and an AC coupled analog-to-digital converter input. The temperature measurement system also implements correlated double sampling for noise cancellation to provide low noise and highly accurate analog-to-digital conversions. The modulator receives a charge domain reference signal generated by a reference charge packet generator incorporating a charge based bandgap subsystem. Therefore, the temperature measurement system can be operated at very low supply voltages, such as 1.0 Vdc. A low noise and highly accurate temperature measurement system is thus realized where temperature measurements of very high resolutions (up to 16 bit) can be attained.