US 12,445,101 B2
Automatic level control circuit, signal source, method for controlling signal source output power, and storage medium
Song Chen, Guangdong (CN); Jie Lin, Guangdong (CN); and Hao Chen, Guangdong (CN)
Assigned to ZTE CORPORATION, Guangdong (CN)
Appl. No. 17/919,784
Filed by ZTE CORPORATION, Guangdong (CN)
PCT Filed Apr. 21, 2021, PCT No. PCT/CN2021/088632
§ 371(c)(1), (2) Date Oct. 19, 2022,
PCT Pub. No. WO2021/213426, PCT Pub. Date Oct. 28, 2021.
Claims priority of application No. 202010317564.3 (CN), filed on Apr. 21, 2020.
Prior Publication US 2023/0155560 A1, May 18, 2023
Int. Cl. H03G 3/30 (2006.01)
CPC H03G 3/3036 (2013.01) [H03G 2201/103 (2013.01); H03G 2201/307 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An automatic level control (ALC) circuit, comprising:
at least two stages of ALC loops, each stage of ALC loop comprising an amplifier, a coupler, a power detector, and an attenuation control circuit sequentially connected, the attenuation control circuit being configured to determine a control voltage of an adjustable attenuator, wherein in each stage of ALC loop, an input terminal of the amplifier in the stage of ALC loop is an input node of the stage of ALC loop, an output terminal of the coupler in the stage of ALC loop is an output node of the stage of the ALC loop, and an output terminal of the attenuation control circuit is connected to a control terminal of the adjustable attenuator;
an input terminal of the adjustable attenuator is an input terminal of the ALC circuit, and an output terminal of the adjustable attenuator is connected to the input node of a first stage of ALC loop; and
the ALC circuit further comprises a single-pole double-throw (SPDT) switch provided between adjacent stages of the at least two stages of ALC loops, wherein
the output node of a previous stage of ALC loop of the adjacent stages of the at least two stages of ALC loops is connected to an input terminal of the SPDT switch, a first output terminal of the SPDT switch is connected to the input node of a next stage of ALC loop of the adjacent stages of the at least two stages of ALC loops, and the output node of a last stage of ALC loop and a second output terminal of the SPDT switch are connected to an output terminal of the ALC circuit.