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. 05, 2012
Filed:
Jan. 04, 2010
Xiao Fei Kuang, Hangzhou, CN;
Kam Chuen Wan, Hong Kong, HK;
Kwai Chi Chan, Hong Kong, HK;
Yat to (William) Wong, Hong Kong, HK;
Kwok Kuen (David) Kwong, Davis, CA (US);
Xiao Fei Kuang, Hangzhou, CN;
Kam Chuen Wan, Hong Kong, HK;
Kwai Chi Chan, Hong Kong, HK;
Yat To (William) Wong, Hong Kong, HK;
Kwok Kuen (David) Kwong, Davis, CA (US);
Abstract
A bandgap reference circuit has trimming-up resistors and trimming-down resistors for bi-directional trimming. PNP transistors have base and collectors grounded and emitters connected to parallel resistors. A difference resistor drives an inverting input of an op amp that drives a transistor that generates the bandgap reference voltage Vbg. A sensing resistor connects Vbg to a splitting node that connects to the non-inverting input through a first parallel resistor. The splitting node also connects through a second parallel resistor to the inverting input. Fuses or switches enable the trimming-up and trimming-down resistors. The trimming-up resistors are in series with the sensing resistor and the trimming-down resistors are in series with an output resistor that connects Vbg to reference voltage Vref. The circuit can be designed for a more typical process since bi-directional trimming allows Vref to be raised or lowered. Many circuits need no trimming when targeted for the typical process.