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. 03, 1990
Filed:
Aug. 31, 1989
Gee H Loh, Singapore, SG;
SGS-Thomson Microelectronics (Pte) Ltd., Singapore, SG;
Abstract
An audio amplifier comprises a first current mirror having an input coupled to an output of a cascade differential pair and an output coupled to an output of a first constant current source. A second constant current source (Q16, Q18, CC10) supplies the voltage reference (Q15) of the first constant current source. Hitherto a resistor has been used instead of the second constant current source to reduce noise. However, using a resistor results in the amplifier having a relatively low power supply rejection ratio, thereby degrading the performance of the amplifier. Accordingly the present invention uses a second constant current source to improve the power supply rejection ratio without degrading the noise performance.