Leakage current detection circuit

Abstract

The invention provides a leakage current detection circuit which is designed based on the closed loop flux gate principle for exciting coil current mean value detection. The leakage current detection circuit comprises a self-excitation square wave oscillating circuit, an active filtering integrator circuit, a feedback resistor, a first filtering circuit and a current detection resistor, wherein the self-excitation square wave oscillating circuit is connected with the first filtering circuit, the active filtering integrator circuit, the current detection resistor and the feedback resistor respectively, the first filtering circuit is connected with the feedback resistor and the current detection resistor respectively, the active filtering integrator circuit is connected with the feedback resistor which is connected with the current detection resistor, the current detection resistor is grounded, and the self-excitation square wave oscillating circuit comprises an exciting coil. The leakage current detection circuit can improve the leakage current detection precision, is simple, and is not influenced by the magnetic conductivity of a magnetic core, the product precision consistency is good and the cost is reduced.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a leakage current detection circuit. Background technique [0002] Leakage current detection plays an important role in equipment safety and personal safety. At present, the principle of leakage current sensors on the market is generally based on even harmonic components or phase difference magnetic modulation principles to measure the leakage current flowing through the primary coil. The detection circuit is more complicated and the cost is higher. At the same time, the two methods Both are open-loop detection, the batch accuracy is greatly affected by the magnetic permeability of the iron core, and the product accuracy consistency is poor. For example, in batch applications, in order to ensure the consistency of accuracy, the back-end adjustment link is more time-consuming and the production cost is higher. high. Contents of the invention [0003] An embodiment of the p...

AI Technical Summary

Problems solved by technology

At present, the principle of leakage current sensors on the market is generally based on even harmonic components or phase difference magnetic modulation principles to measure the leakage current flowing through the primary coil. The detection circuit is more complicated and the cost is higher. At the same time, the two methods Both are open-loop detection, the batch accuracy is greatly affected by the magnetic permeability of the iron core, and the product accuracy consistency is poor. For example, in batch applications, in order to ensure the consistency of accuracy, the back-end adjustment link is more time-consuming and the production cost is higher. high

Images