Circuit scheme for alternating-current and direct-current electric leakage detection system

Abstract

The invention discloses a circuit scheme for an alternating-current and direct-current electric leakage detection system, wherein the circuit is capable of completing direct-current electric leakage detection, alternating-current electric leakage detection and electric leakage sampling link self-detection and the like. The circuit scheme mainly comprises an LDO module for converting externally inputted power supply voltage into a voltage required by electric leakage detection, a frequency division module for carrying out frequency division on a high-frequency clock signal, a logic control module for driving an MOS tube and controlling switching of different working modes, an MOS tube driving module for driving an external electric leakage detection coil, an electric leakage detection coilfor sensing alternating-current and direct-current electric leakage signals and electric leakage self-detection signals, a sampling resistor for converting a current signal flowing through the electric leakage detection coil into a voltage signal, a PGA module for amplifying the sampling signal, a gain control module for controlling the amplification factor of the PGA, an ADC module for carrying out digital-to-analog conversion on the signal, a DSP module for processing alternating-current and direct-current electric leakage signals and electric leakage self-checking signals and a current limiting module for limiting loop currents.

Description

technical field [0001] The invention relates to the technical field of leakage detection and protection circuits, and mainly relates to a DC leakage detection circuit scheme, an AC leakage detection circuit scheme, and a leakage self-inspection circuit scheme. Background technique [0002] Residual current device (RCD) is a widely used safety protection device, used to prevent personal electric shock, electrical fire, electrical equipment damage, etc. According to the different types of detection current, RCD can be divided into: AC type for detecting alternating current, type A for detecting alternating current and pulsating direct current, type B for detecting alternating current, pulsating direct current and smooth direct current, and type B for detecting alternating current, high frequency current, pulsating direct current and smooth direct current DC type B+. [0003] At present, the RCD products that are widely used in the domestic market are mainly AC type and A type...

AI Technical Summary

Problems solved by technology

[0004] In the current leakage detection technology commonly used, it is impossible to achieve full coverage of DC to high-frequency kHz AC leakage detection, and the accuracy and sensitivity are relatively low, the circuit structure is relatively complex, and the cost is relatively high.

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