Circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings

Abstract

The invention provides a circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings. The circuit comprises a current sampling circuit, an analog selection circuit, an analog optical coupling circuit which are connected successively, a secondary differential amplification circuit, an impedance conversion circuit, an effective value conversion circuit and a data processing unit. The current sampling circuit is connected in series in a load by using a low resistance wire wound resistor to send a plurality of channels of low voltage signals to the analog selection circuit, and the analog selection circuit completes more choose one in time division; the analog optical coupling circuit separates a voltage signal portion and a data processing portion on left and right sides; the effective value conversion circuit converts alternating current voltage signals into direct current voltage signals; and the data processing unit samples and calculates the direct current signals to obtain actual current values. The circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings has the advantages that the sampling reliability is high, loaded effects are few, multichannel integration is facilitated, and the cost is low; the system disturbance resisting capability is high; the sampling accuracy is high, and the range is wide; and small signal processing distortion is small. The whole system circuit is simple and easy to implement.

Description

technical field [0001] The invention relates to the field of analysis and measurement control, in particular to a wide-range high-precision multi-channel current detection circuit based on an optocoupler. Background technique [0002] In the road traffic signal controller, it is necessary to carry out real-time sampling control of the AC current value driven by each street lamp to ensure the correctness of the output and monitor the change of the load current, so as to improve the safety of the traffic signal controller. However, many of these applications are currently based on transformers using feedback sampling. Transformers are not only large in size, heavy in weight, but also expensive, which brings a lot of trouble to the subsequent circuit board production and processing. There are also Hall sensors for sampling, but the cost of Hall sensors is high, and the large size is not conducive to multi-channel usage. Contents of the invention [0003] The purpose of the p...

AI Technical Summary

Problems solved by technology

However, many of these applications are currently based on transformers using feedback sampling. Transformers are not only large in size, heavy in weight, but also expensive, which brings a lot of trouble to the subsequent circuit board production and processing.

There are also Hall sensors for sampling, but the cost of Hall sensors is high, and the large size is not conducive to multi-channel usage.

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