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. 19, 2007
Filed:
Jun. 29, 2005
Stuart B. Shacter, Tucson, AZ (US);
Yinming Chen, Tucson, AZ (US);
Stuart B. Shacter, Tucson, AZ (US);
Yinming Chen, Tucson, AZ (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A transconductance stage is provided. The transconductance stage includes a tail current source, a differential pair, and two current mirrors. The input to each of the current mirrors is connected to the drain of a separate one of the transistors in the differential pair. The two current mirrors each have two outputs so that one of the outputs can be used to determine whether the output current exceeds a threshold (e.g. nine-tenths of the tail current). If the source current exceeds the threshold, extra source current is switched in to the output so that output source current is increased. Similarly, if the sink current exceeds the threshold, extra sink current is switched in to the output so that the output sink current is increased. This way, the transconductance stage can supply large output currents in response to a large signal input but maintains low quiescent current for small input signals.