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:
Jul. 08, 2014
Filed:
Dec. 16, 2012
Yang Wang, Suzhou, CN;
Jianzhou Wu, Suzhou, CN;
Xiuqiang Xu, Suzhou, CN;
Yizhong Zhang, Suzhou, CN;
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
A rail to rail differential buffer input stage includes n-type and p-type input differential transistor pairs connected in voltage follower configuration to the power supply rails. A reference voltage generator includes a reference differential transistor pair generating a dynamic reference voltage relative to the common mode input voltage. Dummy n-type and p-type transistor pairs have current conducting paths connected in parallel with the input differential pairs and are controlled by the dynamic reference voltage to divert supply rail current away from and deactivate one of the associated input differential pairs when the common mode input voltage is further from the dynamic reference voltage than a threshold value. Both the dummy pairs conduct and both the input differential pairs are activated when the common mode input voltage is closer to the dynamic reference voltage Vthan the threshold value so that the overall transconductance of the buffer input stage remains constant.