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:
Dec. 17, 1993
Parviz Ghaffaripour, Saratoga, CA (US);
National Semiconductor Corp., Santa Clara, CA (US);
Abstract
A bias control circuit and an associated method in an audio output amplifier provide slow turn-on or turn-off operation of a bias voltage generation circuit, using an external bypass capacitor. A slow rate in the turn-on and turn-off operations in such a bias voltage generation circuit prevents click or pop noises. In one embodiment, two bipolar transistors each responsive to the voltage on an external capacitor are provided to gradually increase the voltage of an output node, which can be used to drive the gate terminal of an MOS transistor in the bias voltage generation circuit. Alternatively, in another embodiment, an MOS inverter, which receives as input the voltage on bypass capacitor, is provided to divert current from a conventional bias circuit. The rate at which the MOS inverter diverts current from the conventional bias circuit controls the slew rate in the turn-off operation of the bias current. Adjustment to this slew rate can be accomplished by adjusting the resistance and capacitance values of resistor and bypass capacitor, respectively.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile