US 12,326,464 B2
Amplifier circuit and measurement apparatus
Kazuaki Haneda, Ueda (JP)
Assigned to HIOKI E.E. CORPORATION, Nagano (JP)
Appl. No. 18/256,744
Filed by HIOKI E.E. CORPORATION, Ueda (JP)
PCT Filed Dec. 3, 2021, PCT No. PCT/JP2021/044410
§ 371(c)(1), (2) Date Jun. 9, 2023,
PCT Pub. No. WO2022/124220, PCT Pub. Date Jun. 16, 2022.
Claims priority of application No. 2020-206343 (JP), filed on Dec. 11, 2020.
Prior Publication US 2024/0027496 A1, Jan. 25, 2024
Int. Cl. G01R 1/30 (2006.01); H03F 3/45 (2006.01)
CPC G01R 1/30 (2013.01) [H03F 3/45475 (2013.01); H03F 2200/129 (2013.01); H03F 2203/45526 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An amplifier circuit configured to amplify an input signal input to a non-inverting input terminal of an operational amplifier, the amplifier circuit comprising:
first and second feedback components configured to feed back an output signal output from the operational amplifier to an inverting input terminal of the operational amplifier; and
a coupling component configured to AC couple the second feedback component and the inverting input terminal of the operational amplifier, wherein
the first feedback component is configured to, together with the coupling component, as a frequency of the output signal is increased, reduce an electric potential to be applied to the inverting input terminal of the operational amplifier with respect to the output signal, and
the second feedback component is configured to generate a predetermined electric potential lower than an electric potential of the output signal, the second feedback component being configured to apply the predetermined electric potential to the inverting input terminal of the operational amplifier via the coupling component.