US 12,388,404 B2
Feedback circuit with adjustable gain and radio frequency circuit utilizing the same
Hang Chang, Taipei (TW); and Chih-Sheng Chen, Taipei (TW)
Assigned to RichWave Technology Corp., Taipei (TW)
Filed by RichWave Technology Corp., Taipei (TW)
Filed on Dec. 20, 2022, as Appl. No. 18/084,572.
Claims priority of application No. 111144532 (TW), filed on Nov. 22, 2022.
Prior Publication US 2024/0171134 A1, May 23, 2024
Int. Cl. H03F 1/34 (2006.01); H03F 1/02 (2006.01); H03F 1/56 (2006.01); H03F 3/19 (2006.01)
CPC H03F 3/19 (2013.01) [H03F 1/0205 (2013.01); H03F 1/56 (2013.01); H03F 2200/222 (2013.01); H03F 2200/387 (2013.01); H03F 2200/451 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A feedback circuit coupled between an output terminal and an input terminal of an amplifier circuit, the feedback circuit comprising:
an input terminal;
an output terminal;
a first set of transistors coupled between the input terminal and the output terminal of the feedback circuit, comprising a first terminal, a second terminal, and a control terminal configured to receive a first control signal, the first set of transistors being configured to provide two or more impedances according to the first control signal, the two or more impedances of the first set of transistors being no lower than a first predetermined impedance; and
a second set of transistors coupled between the input terminal and the output terminal of the feedback circuit, comprising a first terminal coupled to the first terminal of the first set of transistors, a second terminal coupled to the second terminal of the first set of transistors, and a control terminal configured to receive a second control signal, the second set of transistors being configured to provide two or more impedances according to the second control signal, the two or more impedances of the second set of transistors being no lower than a second predetermined impedance.