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:
May. 13, 2003
Filed:
Apr. 18, 2001
Charles Wojslaw, Auburn, CA (US);
Xicor, Inc., Milpitas, CA (US);
Abstract
Methods and apparatus for adjusting DC bias of a radio frequency (RF) amplifier for changing operating conditions such as multiple modulation techniques when no RF is present. A digitally controlled voltage source is programmed to maintain the amplifier bias. The voltage source can be a digitally controlled potentiometer. The amplifier's DC output current can be converted to a voltage and compared to a programmable reference representative of the optimal amplifier bias. The comparator output determines a direction to drive the voltage source. A digital clock is enabled to drive the voltage source when no RF is present. Alternatively, the amplifier's output current can be read by a processor that determines the optimal bias. The bias can be written to a data register that sets the voltage on the voltage source. The system automatically compensates for changes in the amplifier's optimal bias due to aging, temperature, and modulation scheme.