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:
Dec. 12, 1995
Filed:
Jan. 25, 1994
Larry L Harris, Austin, TX (US);
Baker P Scott, III, Austin, TX (US);
Crystal Semiconductor Corporation, Austin, TX (US);
Abstract
An integrated circuit apparatus and method is provided for utilizing voltage dividers and differential amplifiers. An apparatus and method for dividing a voltage with a resistor voltage divider and for employing the voltage divider in an integrated circuit. The resistor voltage divider utilizes inaccessible compensation taps that are placed between nonlinearly spaced output taps. The compensation taps reduce the impact of tap resistance on the voltage divider transfer function. The number of inaccessible compensation taps placed between output taps is dependant upon a chosen tap density that is substantially maintained across the body of the resistor voltage divider. The resistor may be used in integrated circuits employing amplifiers, such as volume control circuitry. A differential amplifier is provided with an input common mode feedback loop that compensates for signal distortion due to a common mode signal. The effects that mode changes in the input transistors have on the differential gain are minimized by the input common mode feedback loop. The differential signal path has only one low frequency mode. The amplifier includes circuitry that acts on the input differential signal and circuitry that acts on the varying input common mode voltage. The common mode feedback is achieved using a variable current sink transistor. The gate voltage of the variable current sink transistor is controlled by the sum of currents flowing through transistors that are connected to the drains of the differential input transistors.