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:
Apr. 24, 2007
Filed:
Jan. 10, 2005
Chau C. Tran, Malden, MA (US);
A. Paul Brokaw, Tucson, AZ (US);
Chau C. Tran, Malden, MA (US);
A. Paul Brokaw, Tucson, AZ (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A bandgap voltage regulator is arranged such that, when a desired output voltage is present between its output and common terminals, current densities in a pair of bipolar transistors having unequal emitter areas are maintained in a fixed ratio. The difference in the transistors' base-emitter voltages is across a resistor, which thus conducts a PTAT current. The regulator also generates a CTAT current, and both the PTAT and CTAT currents are made to flow in another resistor, with the resulting voltages added by superposition. The regulator's resistors are sized such that Vis an integral or fractional multiple of V, where Vis the bandgap voltage for the fabrication process used to make the regulator's transistors, such that Vis temperature invariant, to a first order. The resistors are preferably realized using unit resistors having a predetermined resistance, or series and/or parallel combinations of unit resistors.