Intelligent life testing methods and apparatus for leakage current protection

A method for intelligently testing the life of a leakage current protection device, wherein the leakage current protection device has a first inductive coil N1, a second inductive coil N2, a first input, a second input, a first output electrically coupled to the second input through the first inductive coil N1 and the second inductive coil N2, a second output, a third output, a trip switch SW101 having two LINE terminals and electrically coupled to the first input and the second input, respectively, for receiving an AC power, and two LOAD terminals and electrically coupled to the inputs of an electrical appliance, respectively, a power supply circuit having an input electrically coupled to the first input, and an output electrically coupled to the second output, a trip coil circuit having a switching device VD1 having a gate, an anode and a cathode, an input, an output electrically coupled to the third output, and a leakage current detection circuit having an output electrically coupled to the input of the trip coil circuit, and a power supply inputp electrically coupled to the output of the power supply circuit and the second output, comprising the steps of:

• (i) providing a testing device having:
• (a) a trip mechanism state generator having a first input electrically coupled to the third output of the leakage current protection device, a second input electrically coupled to the first input of the leakage current protection device, a third input electrically coupled to the second input of the leakage current protection device, a first output and a second output, wherein the trip mechanism state generator is adapted for generating a trip mechanism state at the first output and the second output, wherein the trip mechanism state has a first state and a second state, and wherein when the trip mechanism state is in the first state, there is no fault exist in the leakage current protection device, and wherein the trip mechanism state is in the second state, there is at least one fault exists in the leakage current protection device;
• (b) a fault alarm generator having a first input electrically coupled to the first output of the trip mechanism state generator, a second input electrically coupled to the second output of the trip mechanism state generator, and a power supply input electrically coupled to the second output of the leakage current protection device;
• and
• (c) a ground fault simulation unit having an input electrically coupled to the first input of the leakage current protection device, and an output electrically coupled to the first output of the leakage current protection device,
• (ii) generating a simulated ground fault signal during every positive half-wave of the AC power by the ground fault simulation unit;
• (iii) detecting the simulated ground fault signal at the leakage current detection circuit;
• (iv) generating a signal to turn the switching device VD1 into its conductive state so as to allow a current to pass therethrough;
• (v) generating a DC voltage in responsive to a trip mechanism state at the trip mechanism state generator, wherein the trip mechanism state is in a first state that there is no fault exist in the leakage current protection device, or in a second state that there is at least one fault exists in the leakage current protection device;
• (vi) receiving the DC voltage at the fault alarm circuit;
• and
• (vii) indicating whether at least one fault exists in the leakage current protection device.

A leakage current protection device with intelligent life testing, comprising:

• (I) a leakage current protection device having:
• (a) a first inductive coil N1;
• (b) a second inductive coil N2;
• (c) a first input;
• (d) a second input;
• (e) a first output electrically coupled to the second input through the first inductive coil N1 and the second inductive coil N2;
• (f) a second output;
• (g) a third output;
• (h) a trip switch SW101 having two LINE terminals and electrically coupled to the first input and the second input, respectively, for receiving an AC power, and two LOAD terminals and electrically coupled to the inputs of an electrical appliance, respectively;
• (i) a power supply circuit having an input electrically coupled to the first input, and an output electrically coupled to the second output;
• (j) a trip coil circuit having a switching device VD1 having a gate, an anode and a cathode, an input, and an output electrically coupled to the third output;
• and
• (k) a leakage current detection circuit having an output electrically coupled to the input of the trip coil circuit, and a power supply inputp electrically coupled to the output of the power supply circuit and the second output;
• (II) a trip mechanism state generator having a first input electrically coupled to the third output of the leakage current protection device, a second input electrically coupled to the first input of the leakage current protection device, a third input electrically coupled to the second input of the leakage current protection device, a first output and a second output, wherein the trip mechanism state generator is adapted for generating a trip mechanism state at the first output and the second output, wherein the trip mechanism state has a first state and a second state, and wherein when the trip mechanism state is in the first state, there is no fault exist in the leakage current protection device, and wherein the trip mechanism state is in the second state, there is at least one fault exists in the leakage current protection device;
• (III) a fault alarm generator having a first input electrically coupled to the first output of the trip mechanism state generator, a second input electrically coupled to the second output of the trip mechanism state generator, and a power supply input electrically coupled to the second output of the leakage current protection device;
• and
• (IV) a ground fault simulation unit having an input electrically coupled to the first input of the leakage current protection device, and an output electrically coupled to the first output of the leakage current protection device,
• wherein, in operation, the ground fault simulation unit generates a simulated ground fault signal during every positive half-wave of the AC power, the simulated ground fault signal is detected by the leakage current detection circuit, the leakage current detection circuit responsively generates a signal to turn the switching device VD 1 into its conductive state so as to allow a current to pass therethrough, the passed current is converted into a DC voltage in accordance with a trip mechanism state generated by the trip mechanism state generator, the fault alarm circuit receives and analyzes the DC voltage and indicates whether a fault exists in the leakage current protection device.