A DC monitoring system is configured to measure and analyze VFD (Variable Frequency Drive) operational characteristics. The VFD is configured to receive three-phase input power from a standardized source and to provide variable frequency three-phase output power to a three-phase motor. In some applications, the VFD and motor operate at a medium voltage. The VFD can include multiple inverter modules consisting of a DC section and switching section, also referred to as a multiple bus configuration. The DC monitoring system includes a measurement module coupled to each DC bus of the VFD, a data communication network, and a PQube monitoring device for transmitting data signals corresponding to voltage values of the VFD DC bus obtained in a medium voltage compartment to a low voltage compartment for processing and analysis. Processing of the data signals enables comparative and predictive analysis to determine early warning for possible capacitance failure in the VFD.

In an embodiment, an electronic circuit includes: a controller configured to produce a pulse-width-modulated (PWM) signal to control a first current of an electrical load; a redundant current measurement circuit configured to measure the first current and provide first and second current measurement signal; a monitor circuit coupled to the redundant current measurement circuit, the monitor circuit configured to assert a current monitor signal in response to the first and second current measurement signals being found to be matching with each other, wherein the monitor circuit is configured to: detect an absence of the asserted current monitor signal prior to expiry of a threshold time interval, and in response to detecting the absence of the asserted current monitor signal, force the controller to produce, prior to expiry of the threshold time interval, a first PWM signal pulse having a controlled duty-cycle.

A signal detector circuit includes a signal peak detector circuit, a reference voltage generation circuit, and a comparator circuit. The signal peak detector circuit is arranged to receive a plurality of differential voltage input signals, and generate a single-ended peak signal according to the plurality of differential voltage input signals. The reference voltage generation circuit is arranged to generate a single-ended reference voltage signal. The comparator circuit is arranged to receive the single-ended peak signal and the single-ended reference voltage signal, and compare the single-ended peak signal with the single-ended reference voltage signal to generate a signal detection result.

Customer premise equipment (CPE) device may include a power supply failure detector that includes an input to receive an input supply voltage from the power supply, a filter to receive the input supply voltage and produce a filtered input ripple voltage having a predetermined frequency range, a peak detector to process the filtered input ripple voltage from the filter to generate a peak value signal having an amplitude indicative of the peak value of the filtered input ripple voltage, and a level detector to process the peak value signal to generate a signal indicative of a fault condition of the power supply based on the filtered input ripple voltage being determined to be greater than the predetermined peak input ripple voltage. AC coupling may be provided at the input remove DC components from the input supply voltage. An amplifier may amplify the input supply voltage.

A voltage transient detector includes circuitry for transmitting electrical current through a light emitting diode and a fuse that is serially connected between the light emitting diode and a reference potential, such that the light emitting diode is illuminated when the fuse is not blown. The voltage transient detector also includes circuitry for transmitting a controlled amount of electrical current through the fuse in conjunction with an occurrence of a voltage transient at a voltage measurement location, where the voltage transient exceeds a set transient threshold voltage. The controlled amount of electrical current transmitted through the fuse causing the fuse to blow and the light emitting diode to turn off, thereby indicating occurrence of the voltage transient at the voltage measurement location.

A method and authenticator for authenticating a device in a system using the electrical properties of the device is disclosed. Embodiments of the disclosure enable authentication by receiving a plurality of input seed values from a requestor. For each input seed value, load stimuli are generated to produce an electrical load sequence on a power delivery network powering at least part of the system. Noise induced in the power delivery network is measured in response to the electrical load sequence using one or more sensors located on the power delivery network. Based on the measured noise, a dynamic response property (magnitude and phase response as a function of frequency) of the power delivery network corresponding to a respective input seed value can be determined and returned to the requestor.

A timer includes a timing counter configured to generate a timing datum, a clock pulse signal generation circuit configured to generate a clock pulse signal used to operate the timing counter, and an interface circuit configured to receive an access signal, wherein the timing counter is an asynchronous counter, and the clock pulse signal generation circuit generates the clock pulse signal having a first pulse width when there is a possibility that the interface circuit receives the access signal, and generates the clock pulse signal having a second pulse width longer than the first pulse width when there is no possibility that the interface circuit receives the access signal.

A disclosed method includes: setting a connector of an acquisition circuit and an associated capacitor to a predetermined potential; providing an energy pulse of a predetermined first time duration to the connector; at a time occurring substantially at a predetermined second time duration after an end of the predetermined first time duration of the energy pulse, coupling the associated capacitor and the connector of the acquisition circuit; and sampling a voltage being exhibited across the associated capacitor.

A comparison unit (22) compares a measurement value, which is one of changes over time in a voltage value of a bus line (11), distance transition of the voltage value, changes over time in an impedance value of the bus line (11), and distance transition of the impedance value that have been measured, with a normal value, which is one of changes over time in a voltage value of the bus line (11), distance transition of the voltage value, changes over time in an impedance value of the bus line (11), and distance transition of the impedance value in a normal state, and extracts a difference between the measurement value and the normal value. An unauthorized connection determination unit (24) evaluates the difference between the measurement value and the normal value extracted by the comparison unit (22), so as to determine whether an unauthorized device is connected to the bus line (11).

A voltage monitoring device 2 includes: a comparator circuit 31; a state determination circuit 32; a pulse pattern setting circuit 33; an output circuit 36; a VDD port 21; a VSS port 22; an input port 24; and an output port 23. The comparator circuit 31 is connected to the state determination circuit 32. The state determination circuit 32 is connected to the pulse pattern setting circuit 33. The pulse pattern setting circuit is connected to the output port 23 via the output circuit 36.