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:
May. 13, 1986
Filed:
Aug. 03, 1984
Clement A Salama, Toronto, CA;
Satwinder D Malhi, Toronto, CA;
University of Toronto Innovations Foundation, Ontario, CA;
Abstract
The invention provides a class B output stage for an amplifier, more specifically an integrated circuit amplifier for low power, low voltage application, such as a hearing aid amplifier, that is of class B type with consequent negligible quiescent power dissipation, but which avoids the input voltage deadband of conventional class B stages that results in cross-over distortion. The stage uses a bipolar transistor and a field transistor connected in series. The field effect transistor has a gate-source pinch-off voltage that is approximately equal to the base-emitter voltage of the bipolar transistor, so that they are alternately 'on' as the input voltage swings over its full value. In a preferred embodiment the bipolar transistor is an npn type while the field effect transistor is a bipolar compatible p-channel junction field effect transistor (JFET) with pinch-off voltage as close as possible but just less than the base emitter voltage of the bipolar transistor. The circuit is preferable realized in integrated circuit form.