Amplifier eliminating direct current offsets

Abstract

The invention discloses an amplifier eliminating direct current offsets. The amplifier eliminating the direct current offsets comprises a pre-amplifier circuit, a direct current extracting circuit and an isolating circuit, wherein the direct current extracting circuit is used for extracting direct current component signals output by the pre-amplifier circuit, and the isolating circuit is used for generating an electrical current which is identical in size and opposite in direction with direct current offset currents generated by direct current offset voltages carried by two signals to be measured in the pre-amplifier circuit and feeding back and inputting the electrical current to the pre-amplifier circuit according to the received direct current component signals of the direct current extracting circuit. The amplifier sends signals output by a three-operational-amplifier output end to the direct current extracting circuit, extracts the direct current component signals output by the pre-amplifier circuit, and converts direct current components to analogue signals and outputs the analogue signals to the isolating circuit, the isolating circuit converts input voltages to constant flow sources and feeds back to an input end of the pre-amplifier circuit in an inverse mode, and therefore dynamic elimination of the direct current offsets is achieved.

Description

technical field

[0001] The invention belongs to the technical field of circuit design and relates to the design of an amplifying circuit, in particular to the design of a three-operational preamplifier capable of dynamically eliminating the DC offset voltage of the operational amplifier. Background technique

[0002] In the acquisition of electrophysiological signals, it is usually interfered by various noises around, especially the interference of common-mode signals. Under the same process conditions, the way to further improve the common-mode rejection ratio is to increase the amplification of the differential-mode voltage of the preamplifier multiple, but the presence of DC offset voltage in the electrophysiological signal limits the differential-mode voltage amplification of the preamplifier, so it is very difficult to further improve the common-mode rejection ratio of the preamplifier without eliminating the DC bias voltage of.

[0003] Enrique M et al. proposed an AC...

Examples

Embodiment Construction

[0015] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0016] The present invention provides an amplifier for eliminating DC offset, which specifically includes: a preamplifier circuit, a DC signal extraction circuit and an isolation circuit, wherein the preamplifier circuit includes two input terminals and one output terminal, and the two Two input terminals are used to input two signals to be tested; the input terminal of the direct current signal extraction circuit is connected with the output terminal of the preamplifier circuit, and is used to extract the direct current component signal output by the preamplifier circuit; The isolation circuit is used to generate a DC offset voltage with the DC offset voltage of the two signals to be tested according to the received DC component signal of the DC signal extraction circuit. The magnitude of the DC offset current generated in the preamplifier circ...

technical field

[0001] The invention belongs to the technical field of circuit design and relates to the design of an amplifying circuit, in particular to the design of a three-operational preamplifier capable of dynamically eliminating the DC offset voltage of the operational amplifier. Background technique

[0002] In the acquisition of electrophysiological signals, it is usually interfered by various noises around, especially the interference of common-mode signals. Under the same process conditions, the way to further improve the common-mode rejection ratio is to increase the amplification of the differential-mode voltage of the preamplifier multiple, but the presence of DC offset voltage in the electrophysiological signal limits the differential-mode voltage amplification of the preamplifier, so it is very difficult to further improve the common-mode rejection ratio of the preamplifier without eliminating the DC bias voltage of.

[0003] Enrique M et al. proposed an AC...

Examples

Embodiment Construction

[0015] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0016] The present invention provides an amplifier for eliminating DC offset, which specifically includes: a preamplifier circuit, a DC signal extraction circuit and an isolation circuit, wherein the preamplifier circuit includes two input terminals and one output terminal, and the two Two input terminals are used to input two signals to be tested; the input terminal of the direct current signal extraction circuit is connected with the output terminal of the preamplifier circuit, and is used to extract the direct current component signal output by the preamplifier circuit; The isolation circuit is used to generate a DC offset voltage with the DC offset voltage of the two signals to be tested according to the received DC component signal of the DC signal extraction circuit. The magnitude of the DC offset current generated in the preamplifier circ...

Images