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. 25, 1995
Filed:
Aug. 01, 1994
James Wholey, Saratoga, CA (US);
Kevin Negus, Palo Alto, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A bipolar transistor amplifier with improved base biasing is disclosed. In the bias circuit of the present invention, the bias current only varies with the log(log) of variations in .beta. of the NPN transistors, making the circuit particularly resistant to temperature and process induced variations in .beta.. A feedback loop also insures that the bias current will remain constant under normal operating conditions. In several embodiments of the present invention, the bias signal and the input signal are kept separate, reducing interference. The amplifier and bias circuit provides a large amount of voltage headroom even with low supply voltages.