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. 15, 1994
Filed:
Apr. 29, 1993
William C Slemmer, Dallas, TX (US);
Bruce A Doyle, Richardson, TX (US);
SGS-Thomson Microelectronics, Inc., Carrollton, TX (US);
Abstract
A voltage level sense circuit that has temperature compensation is disclosed. The circuit includes charge-sharing capacitors in each of an input leg and a reference leg. The charge-sharing capacitors are precharged to voltages that are integral multiples of the forward bias voltage drop across the base-emitter junction of a bipolar transistor. The bipolar transistors in the input leg differ from those in the reference leg, so that the difference in base-emitter on voltages increases with temperature. The increasing difference in base-emitter on voltage compensates for the decrease in the absolute value of the base-emitter on voltage with temperature. Voltage level sensing is accomplished by sampling the input voltage with a capacitor, charge-sharing the sampled voltage with one of the precharged charge-sharing capacitors, and coupling the charge-shared result to an input of a differential amplifier comparator. The second charge-sharing capacitor, after sharing its charge with another capacitor inserted for purposes of circuit matching, is coupled to the other input of the differential amplifier, and the comparison is performed.