Isolation amplifier circuit based on Sigma-Delta modulation mode

Abstract

The invention discloses an isolation amplifier circuit based on a Sigma-Delta modulation mode. The isolation amplifier circuit comprises a buffer module, a Sigma-Delta modulation module, an on-chip transformer, a Sigma-Delta demodulation module and a filter output processing module. An input signal is input into the Sigma-Delta modulation module through the buffer module to obtain a high-frequencymodulation pulse signal. The Sigma-Delta demodulation module demodulates the high-frequency pulse signal transmitted by the on-chip transformer, filters out a high-frequency component through a filter after demodulation, and obtains an original analog differential input signal through an output processing unit. Defects of photoelectric coupling nonlinear transmission, incapability of differentialsignal transmission by a capacitance isolator and poor noise suppression capability are eliminated by utilizing a transmission mode of an on-chip transformer. Meanwhile, a negative feedback modulation system in the Sigma-Delta modulation module is used for achieving noise shaping, higher precision is achieved, analog Sigma-Delta demodulation is adopted in the demodulation part, and compared witha traditional digital down-sampling filter demodulation scheme, the circuit design is simpler, and the occupied area is smaller.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and in particular relates to an isolation amplifier circuit based on a Sigma-Delta modulation mode. Background technique [0002] The isolation amplifier is a new type of circuit with both isolation and amplification functions based on the isolator and some signal processing circuits. The isolation amplifier is widely used in industrial control, high voltage measurement and medical equipment. application. Traditional linear optocoupler isolators have problems such as large power consumption, narrow bandwidth, high nonlinearity, and poor noise suppression ability of capacitive isolators. At the same time, common PWM modulation has relatively low precision, poor noise suppression ability, and digital down-sampling filter Design demodulation complexity and other issues are limited in high-precision, low-cost applications. Contents of the invention [0003] Aiming at the problems of t...

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Problems solved by technology

[0003] Aiming at the problems of traditional isolation amplifiers in terms of power consumption, bandwidth, nonlinearity, noise suppression capability, precision, and demodulation complexity, the present invention proposes an isolation amplifier circuit based on Sigma-Delta modulation, which has large bandwidth and The characteristics of low power consumption, through the Sigma-Delta modulation circuit, the isolation amplifier has higher precision and stronger noise suppression ability, and effectively reduces the complexity of circuit design and reduces the cost

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