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. 11, 1986
Filed:
Dec. 23, 1985
Thomas P Redfern, San Jose, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
Offsets in a chopper stabilized CMOS operational amplifier are nulled by adjusting the transconductance of the load transistors in the CMOS transistor pairs. This is accomplished by providing a small N channel transistor in parallel with each N channel load transistor of the CMOS pairs. A bias voltage is applied to the gate of one of the transistors and a voltage applied to the gate of the other N channel transistor. The voltage is developed by shorting the inputs to the operational amplifier and closing a feedback path around the input stage to null its offset. The nulling voltage taken at the gate of the other N channel transistor is capacitively stored and used during the subsequent sampling cycle.