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. 25, 2012
Filed:
Dec. 30, 2010
Hendrik Visser, Wijchen, NL;
Roeland Heijna, Nijmegen, NL;
Norbert Van Den Bos, Wijchen, NL;
ST-Ericsson SA, Plan-Les-Ouates, CH;
Abstract
An on-chip power amplifier includes first and second variable capacitors connected in parallel with first and second windings, respectively, of an on-chip balun. The first balun winding connects between the differential outputs of an on-chip differential amplifier. Varying the first variable capacitor changes the imaginary part of the load impedance of the differential amplifier, while varying the second variable capacitor changes the real part of the load impedance of the differential amplifier. In one embodiment, the first and second variable capacitors are generally orthogonal, such that the first and second variable capacitors are less than 25% correlated. As a result, varying the first variable capacitor has little impact on the real part of the load impedance, and varying the second variable capacitor has little impact on the imaginary part of the load impedance. In this way the load impedance can be tuned to the optimum performance.