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. 24, 1997
Filed:
Jan. 31, 1995
Toyojiro Naokawa, Saitama, JP;
Hiroshi Hirayama, Nara, JP;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An audio amplifier with no turn-on pop noise is achieved by the following features: (i) an input stage which operates under zero common-mode input voltage, (ii) an output stage which provides the low voltage end of its voltage swing very close to ground voltage, and (iii) a system of shunt circuits for discharging external capacitors, so as to prevent, upon subsequent power-up, pop noises due to residue charges in the external capacitors. In one embodiment, two peripheral collector transistors are provided to implement a window comparator for discharging the input terminals, the bias voltage and the output terminal of the audio amplifier.