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:
Oct. 12, 2004
Filed:
Apr. 03, 2003
John A. DeFalco, Marlborough, MA (US);
Mikhail S. Shirokov, Methuen, MA (US);
Fairchild Semiconductor Corporation, South Portland, ME (US);
Abstract
A switchable amplifier circuit having a current mirror. The mirror includes: a first current source for producing a reference current; an output transistor having an input electrode and an output electrode; and a current gain device connected between an output of the first current source and the input electrode of the output transistor. A bias current is produced through the output electrode of the output transistor, such bias current being a function of the reference current produced by the first current source. A second current source has an output coupled to an input of the current gain device. The second current source provides a current which is a fraction of the reference current. A switching transistor has an output electrode coupled to: (1) an input of the current gain device; and, (2) an output of the second current source. The switching transistor: (1) sinks the current from the second current source in response to an input signal fed to such switching transistor inhibiting current from the second current source to pass to the current gain device and thereby remove the bias current for the output transistor driving the output transistor to a non-conducting condition; or (2) enables the current from the second current source to pass to the current gain device in response to the input signal fed to such switching transistor driving the output transistor to a conducting condition.