US 12,278,599 B2
Differential amplifier including dual magnetically coupled feedback loops
Ali Fard, Corona Del Mar, CA (US); and Mats Carlsson, Sundbyberg (SE)
Assigned to QuantalRF AG, (CH)
Filed by QuantalRF AG, Zurich (CH)
Filed on Sep. 27, 2021, as Appl. No. 17/486,367.
Claims priority of provisional application 63/084,497, filed on Sep. 28, 2020.
Prior Publication US 2022/0103134 A1, Mar. 31, 2022
Int. Cl. H03F 3/21 (2006.01); H01F 38/14 (2006.01); H03F 1/32 (2006.01); H03F 1/34 (2006.01); H03F 3/24 (2006.01); H03F 1/36 (2006.01); H03F 3/26 (2006.01)
CPC H03F 1/32 (2013.01) [H01F 38/14 (2013.01); H03F 1/3229 (2013.01); H03F 1/3247 (2013.01); H03F 1/347 (2013.01); H03F 3/21 (2013.01); H03F 3/24 (2013.01); H03F 1/36 (2013.01); H03F 3/26 (2013.01); H03F 2200/09 (2013.01); H03F 2200/451 (2013.01); H03F 2200/534 (2013.01); H03F 2200/541 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An amplifier circuit, comprising:
a first amplifier having a first amplifier input and a first amplifier output;
a transformer including a first transformer component having a first primary winding in series with the first amplifier output and a first secondary winding coupled to the first amplifier input wherein the first primary winding and the first secondary winding are arranged such that a portion of a first magnetic field generated by the first primary winding couples to the first secondary winding through a first magnetically coupled feedback loop, thereby providing first feedback from the first amplifier output to the first amplifier input;
a second amplifier having a second amplifier input and a second amplifier output; and
wherein the transformer includes a second transformer component having a second primary winding in series with the second amplifier output and a second secondary winding coupled to the second amplifier input wherein the second primary winding and the second secondary winding are arranged such that a portion of a second magnetic field generated by the second primary winding couples to the second secondary winding through a second magnetically coupled feedback loop, thereby providing second feedback from the second amplifier output to the second amplifier input;
wherein the first primary winding and the second primary winding are configured to provide output current for driving a load impedance included within an output load arrangement connected to the first primary winding and the second primary winding;
wherein the first primary winding has a first end connected to the first amplifier output and a second end directly connected to a first end of a balun and wherein the second primary winding has a first end connected to the second amplifier output and a second end directly connected to a second end of the balun.