A DC Voltage Isolation Sampling Circuit

Abstract

The invention provides a direct current voltage isolation sampling circuit. The direct current voltage isolation sampling circuit comprises a preprocessing circuit, a voltage / frequency oscillating circuit, a magnetic isolating circuit and a rectifying circuit, wherein the preprocessing circuit, the voltage / frequency oscillating circuit, the magnetic isolating circuit and the rectifying circuit are connected in sequence. The direct current voltage isolation sampling circuit further comprises a voltage drop compensating circuit and a filter amplifying circuit. The output end of the rectifying circuit is connected with one input end of the filter amplifying circuit, and the output end of the voltage drop compensating circuit is connected with the other input end of the filter amplifying circuit. The preprocessing circuit is used for buffering and filtering input signals and then outputting the input signals to the voltage / frequency oscillating circuit, the voltage / frequency oscillating circuit modulates high-frequency signals, and the high-frequency signals are transmitted to the rectifying circuit through the magnetic isolating circuit. The rectifying circuit converts alternating current signals into direct current signals, and the direct current signals are compensated through the voltage drop compensating circuit and then are output through the filter amplifying circuit. According to the direct current voltage isolation sampling circuit, a magnetic coupling isolation measuring mode is low in cost compared with finished chips of various existing manufacturers, meanwhile, a discrete component circuit is used for achieving magnetic isolation measurement, high-grade devices can be obtained easily, ageing is avoided, and the problem that parameters drift along with time is solved.

Description

technical field [0001] The invention relates to a DC voltage isolation sampling circuit. Background technique [0002] Measurements such as voltage, current, temperature, pressure, strain, and flow are important components in industrial and process control applications. Such application environments often design hazardous level voltages, transient signals, common-mode voltages, and unstable potentials, which may damage the measurement system and reduce measurement accuracy. To overcome the above drawbacks, electrical isolation is added to the design of measurement systems in industrial applications. [0003] The optocoupler achieves coupling through the transmission of optical signals, there is no direct electrical connection between the input and output, and it has a strong isolation effect. However, due to the shortcomings of optocouplers such as nonlinear current transmission, weak anti-radiation noise and easy aging, they cannot be used in high-grade, long-life and oth...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the technical problems of high cost and no advanced components in the existing DC voltage isolation sampling circuit for sampling magnetic isolation, the present invention provides a DC voltage isolation sampling circuit, which includes a preprocessing circuit, a voltage-frequency oscillation circuit, and a magnetic isolation circuit connected in sequence and a rectification circuit, and also includes a voltage drop compensation circuit and a filter amplifier circuit, the output end of the rectification circuit is connected to one input end of the filter amplifier circuit, and the output end of the voltage drop compensation circuit is connected to the other input end of the filter amplifier circuit; preprocessing The circuit is used to buffer and filter the input signal, and output it to the voltage-frequency oscillation circuit. The voltage-frequency oscillation circuit modulates a high-frequency signal, which is transmitted to the rectifier circuit through the magnetic isolation circuit. The rectifier circuit converts the AC signal into a DC signal. After being compensated by the drop compensation circuit, it is output through the filter amplifier circuit

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