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. 15, 1997
Filed:
Oct. 23, 1995
Parviz Ghaffaripour, Saratoga, CA (US);
Sai L Ting, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An amplifier circuit with improved turn-on and turn-off transient operation includes an amplifier and a controller for controlling the mode of operation of the amplifier during initial and subsequent circuit turn-on and turn-off. The amplifier is biased by a positive power supply voltage and has a differential input which is driven by a reference voltage and a single-ended input signal. Where the output is single-ended, a single amplifier provides a single-ended output signal. Where the output is differential, the amplifier includes cascaded, differential input, single-ended output amplifiers which together provide a differential output signal. One of each of the differential inputs is driven by the reference voltage which, following circuit turn-on, charges to a value of half of the positive power supply voltage. Following circuit turn on and turn-off and during initial charging or discharging, respectively, of the reference voltage, the controller places the amplifier in an operation mode whereby the single-ended output signal follows the relatively slowly charging or discharging reference voltage and the differential output signal remains at zero. When the reference voltage is fully charged, the controller places the amplifier in another operation mode whereby both the single-ended and differential output signals become equal to the sum of the reference voltage and a multiple of the input signal. Hence, turn-on and turn-off transients in the output signal due to circuit turn-on and turn-off are avoided.