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:
Jun. 13, 1995
Filed:
Apr. 30, 1993
Baoson Nguyen, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A bandgap reference circuit (14) in a bandgap voltage reference device (10) generates a bandgap voltage reference (V.sub.BG) at the base of a Q1 transistor (22) and a Q2 transistor (20). A reference current signal I.sub.T flows into the collectors of the Q2 transistor (20) and the Q1 transistor (22) as generated by a difference in base to emitter voltages due to a difference in emitter areas between the Q2 transistor (20) and the Q1 transistor (22). A correction current signal (I.sub.TT) generated by a current squaring circuit (16) is injected into the collector of the Q1 transistor (22) such that the collectors of the Q2 transistor (20) and the Q1 transistor (22) have unequal current values. The current squaring circuitry (16) generates the correction current signal (I.sub.TT) by squaring the reference current signal (I.sub.T) and dividing it into a sampling current signal (I.sub.SC ) generated in a current generator amplifier (18). The collector current difference between the Q2 transistor (20) and the Q1 transistor (22) enable the elimination of the second order temperature coefficient, as well as the first order temperature coefficient, of the base to emitter voltage (V.sub.BE) Of the Q1 transistor (22). In this manner, a bandgap voltage reference (V.sub.BG) becomes more stable, accurate, and less temperature dependent.