Amplifier circuit for broadband and low-noise amplification of a capacitive current source and a sensor system

Abstract

The invention relates to an amplifier circuit (1) for broadband and low-noise amplification of a capacitive current source, preferably of a pyroelectric sensor, comprising a signal input (3), which can be connected to the capacitive current source in a node K1; an input stage (A1), wherein the input stage (A1) is connected to the node K1 at an input (7) of the input stage (A1) and has a node K2 at the output (9) of the input stage (A1), wherein the input stage (A1) is configured to amplify an input voltage at least 3-fold, wherein the input stage (A1) is configured to provide a high-ohm input resistance at the input of the input stage (A1), wherein the input stage (A1) is configured to provide a stable and load-independent voltage at the output of the input stage (A1); an amplifier cascade, wherein the amplifier cascade (11) has at least one first and one second amplifier (A2, A3), each with an input (13, 17) and an output (15, 19), wherein the output (19) of the first amplifier (A2) is connected to the input (17) of the second amplifier (A3) in a node K3, wherein the input (13) of the first amplifier (A2) is connected to the node K2, wherein the output (19) of the second amplifier (A3) is connected to a node K4, wherein the amplifier cascade (11) is configured to generate a high signal amplification with a low phase rotation over a wide frequency range; a feedback network (F1), wherein the feedback network (F1) is connected to the input (7) of the input stage (A1) in the node K1 and the output (19) of the second amplifier (A3) in the node K4, wherein the feedback network (F1) is configured to provide a high-ohm feedback resistor with a parasitic capacitance of less than 0.5 pF, wherein the feedback network (F1) is configured to provide a negative feedback to an assembly comprising the input stage (A1) and the amplifier cascade (11); and a signal output (21), which is connected to a node K5, wherein the node K5 is connected to the node K4 or corresponds to the node K4. The invention also relates to a sensor system.

Dependencies are inferred from the claim text.