Impedance measuring circuit

摘要

A method and circuit for determining a circuit element parameter in a ground fault circuit interrupter circuit. An electrical signal provided to a first node is used to generate another electrical signal at a second node. The electrical signal at the second node is multiplexed with a modulation signal to generate a modulated signal that is then filtered and converted into a digital representation of a portion of the circuit element parameter. The electrical signal at the second node is multiplexed with the modulation signal after it has been phase shifted to produce a modulated signal that is filter and converted into a digital representation of another portion of the circuit element parameter. In another aspect, a slope based solenoid self-test method is used for self-testing in a GFCI circuit. Alternatively, a method for determining a wiring fault is provided using a digital filter.

主权项

1. A circuit element parameter network, comprising:
a transconductance amplifier having first and second inputs and first and second outputs; a first detector having a first input and an output, the first input of the first detector coupled to the first output of the of the transconductance amplifier; a first converter having an input and a first output, the first input of the first detector coupled to the first output of the first converter; and a second detector having a plurality of inputs and an output, a first input of the second detector coupled to the first output of the first converter and the second input of the second detector coupled for receiving the first signal, wherein the first detector comprises:
a first modulator having first and second inputs and an output; anda first low pass filter having an input and an output, the input of the first low pass filter coupled to the output of the first modulator and the output of the first low pass filter serving as the output of the first detector, and the second detector comprises:a second modulator having first and second inputs and an output;a phase shifting element having an input and an output, the input serving as the first input of the second detector; anda second low pass filter having an input and an output, the input of the second low pass filter coupled to the output of the second modulator and the output of the second low pass filter serving as the output of the second detector.