Differential amplifier circuit

Abstract

The present invention proposes a differential amplifier circuit for generating a single-ended signal based on a pair of differential input signals. The differential amplifier circuit includes: an operational amplifier with a negative input terminal, a positive input terminal, a positive output terminal, and a negative output terminal, wherein, the positive output terminal provides a positive output signal as a single-ended signal, and the negative output terminal provides a negative output signal; a first input resistor located between a first differential signal of the pair of differential input signals and the negative input terminal; located between the pair of differential input signals a second input resistor between the second differential signal in the signal and the positive input; a first feedback resistor between the positive output and the negative input; a second feedback resistor between the positive input and ground; A first canceling signal generating device located between the negative output terminal and the negative input terminal; and a second canceling signal generating device located between the negative output terminal and the positive input terminal. The first and second cancellation signal generators are used to reduce the swing of the common-mode input voltage of the operational amplifier.

Description

technical field [0001] The present invention relates to a differential amplifier circuit, in particular to a differential amplifier circuit capable of suppressing common-mode input voltage swings. Background technique [0002] The differential amplifier circuit with double-terminal input structure is widely used in many fields, but the common mode input voltage swing (input common mode voltage swing) often occurs at the virtual ground of the differential amplifier circuit. [0003] As we all know, in the architecture where the signal provided by the differential amplifier circuit to the subsequent circuit is a differential signal, the aforementioned common-mode input voltage swing may not cause serious impact. [0004] However, in the architecture where the signal provided by the differential amplifier circuit to the subsequent circuit is a single-ended signal (single-ended signal), for example, when the differential amplifier circuit is applied in audio devices such as head...

AI Technical Summary

Problems solved by technology

[0004] However, in the architecture where the signal provided by the differential amplifier circuit to the subsequent circuit is a single-ended signal (single-ended signal), for example, when the differential amplifier circuit is applied in audio devices such as headphones, the common-mode input voltage swing will not only increase the differential amplification The total harmonic distortion and noise of the circuit will also reduce the gain and linearity of the differential amplifier circuit, thus making it difficult for the differential amplifier circuit to maintain ideal operating performance in the entire voltage range of the input signal

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