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. 14, 2021
Filed:
Mar. 20, 2019
Cree, Inc., Durham, NC (US);
Haedong Jang, San Jose, CA (US);
Sonoko Aristud, San Jose, CA (US);
Marvin Marbell, Morgan Hill, CA (US);
Madhu Chidurala, Los Altos, CA (US);
Cree, Inc., Durham, NC (US);
Abstract
In an asymmetric Doherty amplifier circuit, one or more shunt reactive components are added to at least one side of an impedance inverter connecting the amplifier outputs, to reduce a capacitance imbalance between the two amplifiers caused by their different parasitic capacitances. This enables the (adjusted) parasitic capacitances to be incorporated into a quarter-wavelength transmission line, having a 90-degree phase shift, for the impedance inverter. In one embodiment, a shunt inductance is connected between the impedance inverter, on the side of the larger amplifier, and RF signal ground. The inductance is sized to resonate away substantially the excess parasitic capacitance of the larger amplifier. In another embodiment, a shunt capacitor is connected on the side of the smaller amplifier, thus raising its total capacitance to substantially equal the parasitic capacitance of the larger amplifier. In other embodiments shunt inductances and/or capacitors may be added to one or both amplifiers, and sized to effectively control a characteristic impedance of the impedance inverter.