Residual current protection circuit, protection method and leakage protection device

Abstract

The invention provides a residual current protection circuit, a protection method and a leakage protection device, and the circuit comprises a detection unit which detects a residual current sampling signal through employing a compensation signal, and obtains a forward input signal; the judgment unit is used for comparing the magnitude relationship between the effective value of the input signal and the effective value of the reference signal and judging whether the residual current protection action is triggered or not; wherein the detection unit converts the part, larger than the compensation signal, of the residual current sampling signal into a first signal, converts the part, smaller than the compensation signal, of the residual current sampling signal into a second signal, and obtains an input signal according to the sum of the first signal and the second signal. Positive and negative power supply does not need to be performed on the operational amplifier when the residual current is detected, a real residual current effective value does not need to be calculated when whether residual current protection is triggered or not is judged, the circuit structure is simpler, and the response speed is higher.

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