There are disclosed apparatus and methods for testing a live circuit powered from an alternating current (AC) voltage. A live circuit tester includes a spread spectrum time domain reflectometer (SSTDR) configured to perform SSTDR measurements of the live circuit and a memory storing one or more ignore distance values. A processor coupled to the SSTDR and the memory detects a potential fault in the live circuit based on results of one or more SSTDR measurements, the potential fault associated with a distance from the apparatus. The processor compares the distance associated with the potential fault with each of the one or more ignore distance values, and stores, in the memory, data defining the potential fault if the associated distance does not match any of the one or more ignore distance values.

A zero current detection device is proposed. The device may include a scaling circuit unit configured to generate a first voltage which is scaled from a target voltage. The device may also include a mirroring circuit unit configured to generate a mirroring current when the first voltage is higher than or equal to a reference voltage. The device may further include a comparator circuit unit configured to compare the target voltage and a ground voltage when the mirroring current is input.

A zero current detection device is proposed. The device may include a scaling circuit unit configured to generate a first voltage which is scaled from a target voltage. The device may also include a mirroring circuit unit configured to generate a mirroring current when the first voltage is higher than or equal to a reference voltage. The device may further include a comparator circuit unit configured to compare the target voltage and a ground voltage when the mirroring current is input.

Embodiments include apparatuses, systems, and methods including a switching converter having an output stage including a power switch or first switching device to convert an input switching signal to an output switching signal and a sensor stage including a second switching device and a third switching device. In embodiments, the sensor stage may be coupled to receive the output switching signal from the first switching device and to substantially replicate a condition of the first switching device to generate a continuous signal rather than a switched signal. In embodiments, the continuous signal may allow detection of a current level. In some embodiments, the current level may indicate an overcurrent event. A digital post-processing circuit may be coupled to the switching device to count a number of overcurrent events according to various embodiments. Other embodiments may also be described and claimed.

Embodiments include apparatuses, systems, and methods including a switching converter having an output stage including a power switch or first switching device to convert an input switching signal to an output switching signal and a sensor stage including a second switching device and a third switching device. In embodiments, the sensor stage may be coupled to receive the output switching signal from the first switching device and to substantially replicate a condition of the first switching device to generate a continuous signal rather than a switched signal. In embodiments, the continuous signal may allow detection of a current level. In some embodiments, the current level may indicate an overcurrent event. A digital post-processing circuit may be coupled to the switching device to count a number of overcurrent events according to various embodiments. Other embodiments may also be described and claimed.

There are disclosed apparatus and methods for testing a live circuit powered from an alternating current (AC) voltage. A zero crossing detector detects zero crossings of the AC voltage. A spread spectrum time domain reflectometer (SSTDR) coupled to the zero crossing detector performs measurements of the live circuit, each measurement synchronized with a zero crossings of the AC voltage. A processor coupled to the SSTDR detects faults in the live circuit based on correlation data provided by the SSTDR.

The disclosure provides a voltage detecting circuit that detects voltage increases and voltage decreases using a diode drop and voltage thresholds. The voltage detecting circuit, referred to as a voltage variation detector, uses the diode to maintain a differential between the voltage being monitored and a voltage threshold. When the diode is reversed bias, the voltage variation detector generates a detecting signal indicating the monitored voltage crossed the voltage threshold. In one example a voltage variation detector is disclosed that includes: (1) a transistor stack that corresponds to a voltage threshold, (2) a transistor diode, and (3) an inverter that receives an input signal and provides an detection signal that controls one or more gates of the transistor stack, wherein the transistor stack and the transistor diode provide the input signal and the detection signal indicates when the voltage crosses the voltage threshold.

The disclosure provides a voltage detecting circuit that detects voltage increases and voltage decreases using a diode drop and voltage thresholds. The voltage detecting circuit, referred to as a voltage variation detector, uses the diode to maintain a differential between the voltage being monitored and a voltage threshold. When the diode is reversed bias, the voltage variation detector generates a detecting signal indicating the monitored voltage crossed the voltage threshold. In one example a voltage variation detector is disclosed that includes: (1) a transistor stack that corresponds to a voltage threshold, (2) a transistor diode, and (3) an inverter that receives an input signal and provides an detection signal that controls one or more gates of the transistor stack, wherein the transistor stack and the transistor diode provide the input signal and the detection signal indicates when the voltage crosses the voltage threshold.

A checking apparatus for checking a number of start-up cycles of a detection device of a motor vehicle includes an electrical switching device for providing an electrical sensor supply for the detection device and includes a contact device for electrically contacting the electrical switching device with the detection device. The electrical switching device has a comparator circuit and, by way of the comparator circuit, a continuous wake up test of the detection device is carried out and thus the number of start cycles is checked.

A checking apparatus for checking a number of start-up cycles of a detection device of a motor vehicle includes an electrical switching device for providing an electrical sensor supply for the detection device and includes a contact device for electrically contacting the electrical switching device with the detection device. The electrical switching device has a comparator circuit and, by way of the comparator circuit, a continuous wake up test of the detection device is carried out and thus the number of start cycles is checked.